446 results on '"Chan YM"'
Search Results
2. Relating the cortical visual contrast gain response to spectroscopy-measured excitatory and inhibitory metabolites in people who experience migraine
- Author
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Lundberg, P, Chan, YM, Glarin, R, Moffat, BA, Bode, S, McKendrick, AM, Lundberg, P, Chan, YM, Glarin, R, Moffat, BA, Bode, S, and McKendrick, AM
- Abstract
OBJECTIVE: This study aimed to determine whether the visual response to flickering checkerboard patterns measured using electroencephalography (EEG) relate to excitatory or inhibitory metabolite levels measured using ultra-high (7Tesla/7T) magnetic resonance spectroscopy (MRS). BACKGROUND: Electrophysiological studies have shown altered visual cortical response amplitudes and contrast gain responses to high contrast flickering patterns in people with migraine. These contrast response anomalies have been argued to represent an imbalance between cortical inhibition and excitation, however the specific mechanism has not been elucidated. METHODS: MRS-measured metabolite levels were obtained from the occipital cortex of 18 participants with migraine and 18 non-headache controls. EEG contrast gain response functions were collected on separate days from a subset of 10 participants with migraine and 12 non-headache controls. Case-control outcome measures were statistically compared between groups both before and after checkboard exposure. RESULTS: No significant difference in GABA and glutamate levels were found between groups nor checkerboard timepoint. Glucose levels were significantly reduced after checkerboard exposure in both participant groups. There was no metabolic signature in visual cortex in response to high-contrast flickering checkboards that distinguished those with migraine and without. There was also no correlation between MRS and EEG measurements in response to the flickering checkerboard. CONCLUSION: Our findings suggest that the mechanisms driving contrast-flickering stimulus aversion are not simplistically reflected by gross changes in metabolic activity in the primary visual cortex.
- Published
- 2022
3. Visual contrast perception in visual snow syndrome reveals abnormal neural gain but not neural noise.
- Author
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Brooks, CJ, Chan, YM, Fielding, J, White, OB, Badcock, DR, McKendrick, AM, Brooks, CJ, Chan, YM, Fielding, J, White, OB, Badcock, DR, and McKendrick, AM
- Abstract
Visual snow syndrome is a neurological condition characterized by a persistent visual disturbance, visual snow, in conjunction with additional visual symptoms. Cortical hyperexcitability is a potential pathophysiological mechanism, which could be explained by increased gain in neural responses to visual input. Alternatively, neural noise in the visual pathway could be abnormally elevated. We assessed these two potential competing neural mechanisms in our studies of visual contrast perception. Cortical hyperexcitation also occurs in migraine, which commonly co-occurs with visual snow syndrome. Therefore, to determine whether the effect of visual snow syndrome can be distinguished from interictal migraine, we recruited four participant groups: controls, migraine alone, visual snow syndrome alone and visual snow syndrome with migraine. In the first experiment, we estimated internal noise in 20 controls, 21 migraine participants and 32 visual snow syndrome participants (16 with migraine) using a luminance increment detection task. In the second experiment, we estimated neural contrast gain in 21 controls, 22 migraine participants and 35 visual snow syndrome participants (16 with migraine) using tasks assessing sensitivity to changes in contrast from a reference. Contrast gain and sensitivity were measured for the putative parvocellular and 'on' and 'off' magnocellular pathways, respectively. We found that luminance increment thresholds and internal noise estimates were normal in both visual snow syndrome and migraine. Contrast gain measures for putative parvocellular processing and contrast sensitivity for putative off magnocellular processing were abnormally increased in visual snow syndrome, regardless of migraine status. Therefore, our results indicate that visual snow syndrome is characterized by increased neural contrast gain but not abnormal neural noise within the targeted pathways.
- Published
- 2022
4. REPRODUCTIVE BIOLOGY OF THE ENDANGERED AND ENDEMIC PALM JOHANNESTEIJSMANNIA LANCEOLATA (ARECACEAE)
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Chan, YM, Lim, AL, and Saw, LG
- Published
- 2011
5. IUGR is Commonly Observed among Prenatally Diagnosed Chromosome 4p Deletion Syndrome
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Fu Hy, Chan Ym, Huang Hq, Wei Sk, Leung Ty, Su Js, Zhang Sj, Li W, Choy Kw, Yang Sh, Qin Z, Cao Y, Luo Js, Zhu Xf, Lu Wl, Jiang Tt, Zhang Y, and Wei Hw
- Subjects
Genetics ,General Medicine ,Biology ,Chromosome 4p deletion - Abstract
Objective: our study aimed at retrospectively assessing the abnormal prenatal ultrasound findings of chromosome 4p deletion syndrome. Methods: 21 cases with abnormal sonographic signs revealed 4p deletion by Chromosome Microarray (CMA) in this retrospective analysis. Clinical information and molecular basis of this cohort were compared with those from other two groups in China, the critical region related to special ultrasound findings was mapped with the smallest regions of overlap. Results: This is the largest prenatal series to evaluate the prenatal ultrasound features of 4p deletion syndrome detected by CMA. Firstly we refined the relationship between the genomic coordinates with IUGR in chromosome 4p terminal deletion syndrome. Additional chromosomal abnormalities was identified in 12 cases. Intrauterine embryonic arrest was diagnosed at first trimester for 9 cases. The most consistent ultrasound indicator was IUGR (95.5%), and the smallest region response for IUGR correspond to a 2.05Mb at 4p16.3-pter (chr4: 68,345-2,121,057, hg19). Increased Nuchal Translucency (NT) could be a risk factor for predicting WHS at first-trimester pregnancy with the rate of 16.6% from our data. A 3.6Mb microdeletion located at 4p16.3-pter (chr4: 68,345-3,753,422, hg19) might be the candidate region associated with increased NT. Conclusion: We identified IUGR as the most common feature in prenatal 4p terminal deletion and Wolf-Hirschhorn syndrome. The existence of additional CNVs may contribution to possible explanations for the clinical heterogeneity of this syndrome. Prenatal findings of IUGR, increased NT or early spontaneous abortion should warrant the diagnosis of 4p terminal deletion WHS.
- Published
- 2021
6. A Study Protocol for an Open-Label Feasibility Treatment Trial of Visual Snow Syndrome With Transcranial Magnetic Stimulation
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Grande, M, Lattanzio, L, Buard, I, McKendrick, AM, Chan, YM, Pelak, VS, Grande, M, Lattanzio, L, Buard, I, McKendrick, AM, Chan, YM, and Pelak, VS
- Abstract
Background: Visual Snow (VS) syndrome is believed to be due to aberrant central visual processing. Positron Emission Tomography (PET) brain imaging and visual evoked potential studies provide evidence for excessive neuronal activity in the medial temporal lobe, specifically the lingual gyrus, and suggest the VS syndrome is a hyperexcitability syndrome. These data provide the basis for consideration of repetitive transcranial magnetic stimulation (rTMS) as a potential treatment for the VS syndrome. Objective: To publish the study protocol for a pilot study underway at the University of Colorado School of Medicine to investigate the use of rTMS intervention to improve symptoms and visual dysfunction associated with VS. The study aims to determine the adverse events and drop-out rate, evaluate performance of outcome measures, including a novel VS symptom scale, and describe changes in outcomes associated with treatment. Methods and Design: Up to 10 participants meeting criteria for VS syndrome, age 19-65 years, will undergo an open-label intervention consisting of 10 rTMS sessions, occurring 5 days a week over a 2-week period. Participants will complete pre-treatment and post-treatment assessments that include: the Colorado Visual Snow Scale (CVSS), the National Eye Institute Visual Functional Questionnaire-25 (VFQ-25), the General Anxiety Disorder-7 scale (GAD-7), and three psychophysical visual processing tasks. Discussion: Knowledge gained from this pilot study will inform future study planning and provide valuable lessons for future investigation of rTMS for the VS syndrome. An overview of study proceedings thus far demonstrates recruitment challenges associated with the COVID-19 pandemic, and additional challenges that are unique to the VS syndrome and to treatment schedules associated with TMS. Registration: This study has been approved by the Colorado Multiple Institutional Review Board. ClinicalTrials.gov Identifier: NCT04925232.
- Published
- 2021
7. Orientation-dependency of perceptual surround suppression and orientation decoding of centre-surround stimuli are preserved with healthy ageing
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Nguyen, BN, Chan, YM, Bode, S, McKendrick, AM, Nguyen, BN, Chan, YM, Bode, S, and McKendrick, AM
- Abstract
A key visual neuronal property that is mirrored in human behaviour is centre-surround contrast suppression, which is orientation-dependent. When a target is embedded in a high-contrast surround, the centre appears reduced in contrast, the magnitude of which depends on the relative orientation between centre and surround. Previous reports demonstrate changes in perceptual surround suppression with ageing; however, whether the orientation-dependency of surround suppression is impacted by ageing has not been explored. Here, we tested 18 younger (aged 19–33) and 18 older (aged 60–77) adults. Perceptual surround suppression was stronger for parallel than orthogonal stimuli; however contrary to previous work, here we found no difference in perceptual suppression strength between age-groups. In the same participants, we measured event-related potentials (ERPs) and conducted multivariate pattern analysis to confirm that parallel and orthogonal centre-surround stimuli elicit distinguishable brain activity, predominantly over occipital areas. Despite a delay in the first prominent ERP component (P1) in response to each pattern, older adults showed similar decoding of orientation information (i.e. distinguish between parallel and orthogonal centre-surround stimuli from 70 ms post-stimulus onset) as younger adults. This suggests that sufficient information to distinguish orientation in centre-surround stimuli becomes available to the older human brain as early as in younger adults.
- Published
- 2020
8. Illusory Motion Perception Is Associated with Contrast Discrimination but Not Motion Sensitivity, Self-Reported Visual Discomfort, or Migraine Status
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He, C, Chan, YM, McKendrick, AM, Nguyen, B, He, C, Chan, YM, McKendrick, AM, and Nguyen, B
- Abstract
PURPOSE: Altered visual processing of motion and contrast has been previously reported in people with migraine. One possible manifestation of this altered visual processing is increased self-reported susceptibility to visual illusions of contrast and motion. Here, we use the Fraser-Wilcox illusion to explore individual differences in motion illusion strength in people with and without migraine. The motion-inducing mechanisms of the Fraser-Wilcox illusion are purported to be contrast dependent. To better understand the mechanisms of the illusion, as well as visual processing anomalies in migraine, we explored whether migraine status, susceptibility to visual discomfort, contrast discrimination, or motion sensitivity are related to quantified motion illusion strength. METHODS: Thirty-six (16 with aura, 20 without aura) people with migraine and 20 headache-free controls participated. Outcome measures were motion illusion strength (the physical motion speed that counterbalanced the illusory motion), motion sensitivity, and contrast discrimination thresholds (measured for each contrast pair that formed part of the illusory motion stimulus). Typical daily visual discomfort was self-reported via questionnaire. RESULTS: Motion illusion strength was negatively correlated with contrast discrimination threshold (r = -0.271, P = 0.04) but was not associated with motion sensitivity or migraine status. People with migraine with aura reported experiencing visual discomfort more frequently than the control group (P = 0.001). Self-reported visual discomfort did not relate to quantified perceptual motion illusion strength. CONCLUSIONS: Individuals with better contrast discrimination tend to perceive faster illusory motion regardless of migraine status.
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- 2020
9. Management of pediatric patients with DSD and ambiguous genitalia: Balancing the childs moral claims to self-determination with parental values and preferences
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Chan Ym, Tishelman A, Diamond Da, ohnson J, and Swartz J
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Ambiguous genitalia ,Self-determination ,Moral Claims ,media_common.quotation_subject ,Psychology ,Developmental psychology ,media_common - Published
- 2019
10. Relating excitatory and inhibitory neurochemicals to visual perception: A magnetic resonance study of occipital cortex between migraine events
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Solomon, SG, Chan, YM, Pitchaimuthu, K, Wu, Q-Z, Carter, OL, Egan, GF, Badcock, DR, McKendrick, AM, Solomon, SG, Chan, YM, Pitchaimuthu, K, Wu, Q-Z, Carter, OL, Egan, GF, Badcock, DR, and McKendrick, AM
- Abstract
Certain perceptual measures have been proposed as indirect assays of brain neurochemical status in people with migraine. One such measure is binocular rivalry, however, previous studies have not measured rivalry characteristics and brain neurochemistry together in people with migraine. This study compared spectroscopy-measured levels of GABA and Glx (glutamine and glutamate complex) in visual cortex between 16 people with migraine and 16 non-headache controls, and assessed whether the concentration of these neurochemicals explains, at least partially, inter-individual variability in binocular rivalry perceptual measures. Mean Glx level was significantly reduced in migraineurs relative to controls, whereas mean occipital GABA levels were similar between groups. Neither GABA levels, nor Glx levels correlated with rivalry percept duration. Our results thus suggest that the previously suggested relationship between rivalry percept duration and GABAergic inhibitory neurotransmitter concentration in visual cortex is not strong enough to enable rivalry percept duration to be reliably assumed to be a surrogate for GABA concentration, at least in the context of healthy individuals and those that experience migraine.
- Published
- 2019
11. International Gender Diversity Genomics Consortium. The Biological Contributions to Gender Identity and Gender Diversity: Bringing Data to the Table
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Jesse M. Ehrenfeld, Kreukels Bpc, Heijer, Michael S. Irwig, Danielle Posthuma, Esteva I, Lauren B. Beach, Amy C. Tishelman, Raynor L, Chan Ym, Lea K. Davis, and Eske M. Derks
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Gender identity ,Gender diversity ,Table (database) ,Gender studies ,Genomics ,Psychology - Published
- 2018
12. Audiovisual Temporal Perception in Aging: The Role of Multisensory Integration and Age-Related Sensory Loss
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Brooks, CJ, Chan, YM, Anderson, AJ, McKendrick, AM, Brooks, CJ, Chan, YM, Anderson, AJ, and McKendrick, AM
- Abstract
Within each sensory modality, age-related deficits in temporal perception contribute to the difficulties older adults experience when performing everyday tasks. Since perceptual experience is inherently multisensory, older adults also face the added challenge of appropriately integrating or segregating the auditory and visual cues present in our dynamic environment into coherent representations of distinct objects. As such, many studies have investigated how older adults perform when integrating temporal information across audition and vision. This review covers both direct judgments about temporal information (the sound-induced flash illusion, temporal order, perceived synchrony, and temporal rate discrimination) and judgments regarding stimuli containing temporal information (the audiovisual bounce effect and speech perception). Although an age-related increase in integration has been demonstrated on a variety of tasks, research specifically investigating the ability of older adults to integrate temporal auditory and visual cues has produced disparate results. In this short review, we explore what factors could underlie these divergent findings. We conclude that both task-specific differences and age-related sensory loss play a role in the reported disparity in age-related effects on the integration of auditory and visual temporal information.
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- 2018
13. Spatial vision in older adults: perceptual changes and neural bases
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McKendrick, AM, Chan, YM, Nguyen, BN, McKendrick, AM, Chan, YM, and Nguyen, BN
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PURPOSE: The number of older adults is rapidly increasing internationally, leading to a significant increase in research on how healthy ageing impacts vision. Most clinical assessments of spatial vision involve simple detection (letter acuity, grating contrast sensitivity, perimetry). However, most natural visual environments are more spatially complicated, requiring contrast discrimination, and the delineation of object boundaries and contours, which are typically present on non-uniform backgrounds. In this review we discuss recent research that reports on the effects of normal ageing on these more complex visual functions, specifically in the context of recent neurophysiological studies. RECENT FINDINGS: Recent research has concentrated on understanding the effects of healthy ageing on neural responses within the visual pathway in animal models. Such neurophysiological research has led to numerous, subsequently tested, hypotheses regarding the likely impact of healthy human ageing on specific aspects of spatial vision. SUMMARY: Healthy normal ageing impacts significantly on spatial visual information processing from the retina through to visual cortex. Some human data validates that obtained from studies of animal physiology, however some findings indicate that rethinking of presumed neural substrates is required. Notably, not all spatial visual processes are altered by age. Healthy normal ageing impacts significantly on some spatial visual processes (in particular centre-surround tasks), but leaves contrast discrimination, contrast adaptation, and orientation discrimination relatively intact. The study of older adult vision contributes to knowledge of the brain mechanisms altered by the ageing process, can provide practical information regarding visual environments that older adults may find challenging, and may lead to new methods of assessing visual performance in clinical environments.
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- 2018
14. Daily vision testing can expose the prodromal phase of migraine
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McKendrick, AM, Chan, YM, Vingrys, AJ, Turpin, A, Badcock, DR, McKendrick, AM, Chan, YM, Vingrys, AJ, Turpin, A, and Badcock, DR
- Abstract
Background Several visual tasks have been proposed as indirect assays of the balance between cortical inhibition and excitation in migraine. This study aimed to determine whether daily measurement of performance on such tasks can reveal perceptual changes in the build up to migraine events. Methods Visual performance was measured daily at home in 16 non-headache controls and 18 individuals with migraine using a testing protocol on a portable tablet device. Observers performed two tasks: luminance increment detection in spatial luminance noise and centre surround contrast suppression. Results Luminance thresholds were reduced in migraine compared to control groups ( p < 0.05), but thresholds did not alter across the migraine cycle; while headache-free, centre-surround contrast suppression was stronger for the migraine group relative to controls ( p < 0.05). Surround suppression weakened at around 48 hours prior to a migraine attack and strengthened to approach their headache-free levels by 24 hours post-migraine (main effect of timing, p < 0.05). Conclusions Daily portable testing of vision enabled insight into perceptual performance in the lead up to migraine events, a time point that is typically difficult to capture experimentally. Perceptual surround suppression of contrast fluctuates during the migraine cycle, supporting the utility of this measure as an indirect, non-invasive assay of the balance between cortical inhibition and excitation.
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- 2018
15. Behavioral measures of cortical hyperexcitability assessed in people who experience visual snow
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McKendrick, AM, Chan, YM, Tien, M, Millist, L, Clough, M, Mack, H, Fielding, J, White, OB, McKendrick, AM, Chan, YM, Tien, M, Millist, L, Clough, M, Mack, H, Fielding, J, and White, OB
- Abstract
OBJECTIVE: To determine whether visual perceptual measures in people who experience visual snow are consistent with an imbalance between inhibition and excitation in visual cortex. METHODS: Sixteen patients with visual snow and 18 controls participated. Four visual tasks were included: center-surround contrast matching, luminance increment detection in noise, and global form and global motion coherence thresholds. Neuronal architecture capable of encoding the luminance and contrast stimuli is present within primary visual cortex, whereas the extraction of global motion and form signals requires extrastriate processing. All these tasks have been used previously to investigate the balance between inhibition and excitation within the visual system in both healthy and diseased states. RESULTS: The visual snow group demonstrated reduced center-surround contrast suppression (p = 0.03) and elevated luminance increment thresholds in noise (p = 0.02). Groups did not differ on the global form or global motion task. CONCLUSION: Our study demonstrates that visual perceptual measures involving the suprathreshold processing of contrast and luminance are abnormal in a group of individuals with visual snow. Our data are consistent with elevated excitability in primary visual cortex; however, further research is required to provide more direct evidence for this proposed mechanism. The ability to measure perceptual differences in visual snow reveals promise for the future development of clinical tests to assist in visual snow diagnosis and possibly a method for quantitatively assaying any benefits of treatments.
- Published
- 2017
16. Spatio-temporal patterns of event-related potentials related to audiovisual synchrony judgments in older adults
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Chan, YM, Pianta, MJ, Bode, S, McKendrick, AM, Chan, YM, Pianta, MJ, Bode, S, and McKendrick, AM
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Older adults have altered perception of the relative timing between auditory and visual stimuli, even when stimuli are scaled to equate detectability. To help understand why, this study investigated the neural correlates of audiovisual synchrony judgments in older adults using electroencephalography (EEG). Fourteen younger (18-32 year old) and 16 older (61-74 year old) adults performed an audiovisual synchrony judgment task on flash-pip stimuli while EEG was recorded. All participants were assessed to have healthy vision and hearing for their age. Observers responded to whether audiovisual pairs were perceived as synchronous or asynchronous via a button press. The results showed that the onset of predictive sensory information for synchrony judgments was not different between groups. Channels over auditory areas contributed more to this predictive sensory information than visual areas. The spatial-temporal profile of the EEG activity also indicates that older adults used different resources to maintain a similar level of performance in audiovisual synchrony judgments compared with younger adults.
- Published
- 2017
17. Development and Validation of Knowledge, Attitude and Practice on Healthy Lifestyle Questionnaire (KAP-HLQ) for Malaysian Adolescents
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Yit Siew Chin, Hiew Cc, Chan Ym, and Mohd Nasir Mt
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medicine.medical_specialty ,Medical education ,medicine.anatomical_structure ,business.industry ,Open access publishing ,Alternative medicine ,Medicine ,Library science ,business ,Citation ,Chin ,Biomedical sciences - Abstract
Citation: Hiew CC, Chin YS, Chan YM, Mohd Nasir MT (2015) Development and Validation of Knowledge, Attitude and Practice on Healthy Lifestyle Questionnaire (KAP-HLQ) for Malaysian Adolescents. J Nutr Health Sci 2(4): 407. doi: 10.15744/2393-9060.2.407 Volume 2 | Issue 4 Journal of Nutrition and Health Sciences
- Published
- 2015
18. Surgical outcome of daytime and out-of-hours surgery for elderly patients with hip fracture
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Chan, YM, primary, Tang, N, additional, and Chow, Simon KH, additional
- Published
- 2017
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19. Impact of replacing Chinese ethnicity-specific fetal biometry charts with the INTERGROWTH-21st standard
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Cheng, YKY, primary, Leung, TY, additional, Lao, TTH, additional, Chan, YM, additional, and Sahota, DS, additional
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- 2016
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20. Milk Drinking Patterns among Malaysian Urban Children of Different Household Income Status
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Maznorila Mohamad, Sarina Sariman, Yusof Bnm, Yit Siew Chin, Chan Ym, Huang Slm, Zalilah Mohd Shariff, and Geok Lin Khor
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Consumption (economics) ,Pediatrics ,medicine.medical_specialty ,Kuala lumpur ,business.industry ,Dietary intake ,Dental care ,Tooth brushing ,Environmental health ,Optimum growth ,Household income ,Medicine ,business ,Socioeconomic status - Abstract
Introduction: Good oral hygiene protects against oral diseases such as caries and gum infections. Twice daily tooth brushing with fluoride pastes and flossing are recommended to keep mouth clean and reduce plaque bacterial growth. Poor access to oral cleaning material and dental care services expose children from poor backgrounds to oral diseases. Background: Milk consumption is popular in Malaysia especially among the younger ages. Nonetheless, there is a lack of quantitative data on milk consumption by children in Malaysia. Methods: A cross-sectional study was undertaken on a sample of 749 children aged 1-10 years in the metropolitan areas of Kuala Lumpur. Approximately similar proportions of children were selected from low, middle and high household income categories. Socioeconomic background, dietary intake based on 24-hour recall and food records, were obtained for each child. Results: Prevalence of milk drinking was highest among aged 1-3 years (90.6%) followed by 86.1% aged 4-6 years, and 73.7% among ages 7-10 years. The youngest age group consumed averagely 3.5 (3.1 – 3.8) cups (200ml/cup) of milk daily, exceeding the recommendation of 2-3 cups a day by the Ministry of Health, Malaysia. There were no significant differences in the mean amounts of milk consumed among ages 1-3 years from low to high income categories. Children aged 4-6 years consumed, on average, 2.2 (1.9 – 2.4) cups/day, which is within the MOH recommendation, while that for ages 7-10 years, at 1.07 (0.9–1.2) cups/day, is below the recommendation. Conclusion: Parents of young children should be advised on the nutritional importance of providing foods from a variety of sources, so that the children obtain the right balance and mix of nutrients for optimum growth.
- Published
- 2012
21. Reduced audiovisual recalibration in the elderly
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Chan, YM, Pianta, MJ, McKendrick, AM, Chan, YM, Pianta, MJ, and McKendrick, AM
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Perceived synchrony of visual and auditory signals can be altered by exposure to a stream of temporally offset stimulus pairs. Previous literature suggests that adapting to audiovisual temporal offsets is an important recalibration to correctly combine audiovisual stimuli into a single percept across a range of source distances. Healthy aging results in synchrony perception over a wider range of temporally offset visual and auditory signals, independent of age-related unisensory declines in vision and hearing sensitivities. However, the impact of aging on audiovisual recalibration is unknown. Audiovisual synchrony perception for sound-lead and sound-lag stimuli was measured for 15 younger (22-32 years old) and 15 older (64-74 years old) healthy adults using a method-of-constant-stimuli, after adapting to a stream of visual and auditory pairs. The adaptation pairs were either synchronous or asynchronous (sound-lag of 230 ms). The adaptation effect for each observer was computed as the shift in the mean of the individually fitted psychometric functions after adapting to asynchrony. Post-adaptation to synchrony, the younger and older observers had average window widths (±standard deviation) of 326 (±80) and 448 (±105) ms, respectively. There was no adaptation effect for sound-lead pairs. Both the younger and older observers, however, perceived more sound-lag pairs as synchronous. The magnitude of the adaptation effect in the older observers was not correlated with how often they saw the adapting sound-lag stimuli as asynchronous. Our finding demonstrates that audiovisual synchrony perception adapts less with advancing age.
- Published
- 2014
22. Otosyphilis: A review of treatment and outcome in a case series at a Singapore hospital
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Mueller, S, Chan, YM, Mueller, S, and Chan, YM
- Published
- 2014
23. Difficult intubation in a patient with vallecular cyst
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Kothandan, H, primary, Ho, VK, additional, Chan, YM, additional, and Wong, T, additional
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- 2013
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24. Head and Neck Cancer After Foreign Body Ingestion
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Teo, DTW, primary, Loy, AHC, additional, Goh, YH, additional, and Chan, YM, additional
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- 2004
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25. Dietary calcium intake in postmenopausal Malaysian women: comparison between the food frequency questionnaire and three-day food records
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Chee, WSS, primary, Suriah, AR, additional, Zaitun, Y, additional, Chan, SP, additional, Yap, SL, additional, and Chan, YM, additional
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- 2002
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26. Prevalence of glucose intolerance, and associated antenatal and historical risk factors among Malaysian women with a history of gestational diabetes mellitus.
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Chew WF, Rokiah P, Chan SP, Chee SS, Lee LF, and Chan YM
- Published
- 2012
27. Diacylglycerol oil reduces body fat but does not alter energy or lipid metabolism in overweight, hypertriglyceridemic women.
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Yuan Q, Ramprasath VR, Harding SV, Rideout TC, Chan YM, and Jones PJ
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- 2010
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28. Olive oil containing olive oil fatty acid esters of plant sterols and dietary diacylglycerol reduces low-density lipoprotein cholesterol and decreases the tendency for peroxidation in hypercholesterolaemic subjects.
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Chan YM, Demonty I, Pelled D, and Jones PJ
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- 2007
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29. The relationship between diabetes knowledge and compliance among Chinese with non-insulin dependent diabetes mellitus in Hong Kong.
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Chan YM and Molassiotis A
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TYPE 2 diabetes , *PATIENT compliance - Abstract
This study examines the relationship between diabetes knowledge and compliance among Chinese with non-insulin dependent diabetes mellitus (NIDDM) in Hong Kong. A cross-sectional design was used to collect data through structured self-report interviews based on validated scales assessing diabetes knowledge, compliance behaviours and demographic data. The Diabetes Knowledge Scale was used to sample knowledge in the major areas of basic physiology of diabetes and general principles of diabetes care. Compliance level was assessed by using the Compliance Behaviour Questionnaire, inspection of patients' feet and the value of HbA1c. A convenience sample of 52 Chinese with NIDDM receiving out-patient diabetes care participated in the study on a voluntary basis. Descriptive and correlational statistical analyses were used to analyse the data. The findings indicated that there was no association between diabetes knowledge and compliance. There was a gap between what the patients were taught and what they were actually doing. Most of the patients gained higher marks on factual knowledge on diabetes but lost marks on the application of knowledge to their real life situations. Strategies are suggested to close the 'knowledge-action gap' and increase patients' motivation and ability to comply with the health regimen. [ABSTRACT FROM AUTHOR]
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- 1999
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30. Three-dimensional cephalometric norms of Chinese adults in Hong Kong with balanced facial profile.
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Cheung LK, Chan YM, Jayaratne YS, and Lo J
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OBJECTIVE: The objectives of this study were (1) to develop a 3D cephalometric analysis scheme applicable to assessing dentofacial deformities; and (2) to create a normative database of 3D cephalometric measurements for adult Chinese in Hong Kong. STUDY DESIGN: A cross-sectional study was conducted on 50 male and 50 female adults with normal balanced facial profile and occlusion. Cone-beam computed tomography and stereo photogrammetry imaging were performed on all subjects. Three-dimensional virtual models were generated from imaging data, and cephalometric analysis was performed using specialized software. A new 3D cephalometric analysis scheme appropriate for orthognathic surgery as well as a new reference plane (supraorbital margin plane) for midfacial assessment was used in this study. RESULTS: The cephalometric norms generated in this study were comparable with those reported in the literature for conventional 2D cephalometric analysis and the unique features of Chinese faces. The results also showed significant differences between males and females in most of the facial height measurements (P < .01). CONCLUSIONS: This is the first database of 3D cephalometric norms based on CBCT and 3D photogrammetry of the Chinese population in Hong Kong. This can be a useful reference for characterizing facial deformities in 3 dimensions. Moreover, 3D cephalometric analysis has the potential of incorporating new measurement methods that are difficult if not impossible in 2D cephalometric analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2011
31. Socioeconomic Status and Health Outcomes in Malaysian Adults: Findings From the National Health and Morbidity Survey (NHMS).
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Khaw WF, Chan YM, Alias N, Tan L, Nasaruddin NH, Tham SW, and Ahmad NA
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The relationship between socioeconomic status (SES) and health outcomes has garnered significant attention. However, there is a limited amount of research exploring the association between SES and the risk of metabolic syndrome in Malaysian adults. This study aims to determine the association between SES and risk of hypertension, diabetes and obesity. By using data from the National Health and Morbidity Survey (NHMS), SES was derived through principal component analysis involving six variables. Two different SES components were identified and labeled as "social status" and "wealth status." Among the participants, 36% were diagnosed with hypertension, 18% with obesity, and 21% with diabetes. Adults with high wealth and social status showed a significantly increased risk of obesity. Meanwhile, high social status was significantly associated with a reduction in the risk of hypertension and diabetes. A comprehensive understanding of the associations between SES and noncommunicable diseases could facilitate initiatives that promote healthy lifestyle behaviors, thereby enhancing the holistic well-being of Malaysians., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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- 2024
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32. Digital Light Processing to Afford High Resolution and Degradable CO 2 -Derived Copolymer Elastomers.
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Poon KC, Segal M, Bahnick AJ, Chan YM, Gao C, Becker ML, and Williams CK
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Vat photopolymerization 3D printing has proven very successful for the rapid additive manufacturing (AM) of polymeric parts at high resolution. However, the range of materials that can be printed and their resulting properties remains narrow. Herein, we report the successful AM of a series of poly(carbonate-b-ester-b-carbonate) elastomers, derived from carbon dioxide and bio-derived ϵ-decalactone. By employing a highly active and selective Co(II)Mg(II) polymerization catalyst, an ABA triblock copolymer (M
n =6.3 kg mol-1 , ÐM =1.26) was synthesized, formulated into resins which were 3D printed using digital light processing (DLP) and a thiol-ene-based crosslinking system. A series of elastomeric and degradable thermosets were produced, with varying thiol cross-linker length and poly(ethylene glycol) content, to produce complex triply periodic geometries at high resolution. Thermomechanical characterization of the materials reveals printing-induced microphase separation and tunable hydrophilicity. These findings highlight how utilizing DLP can produce sustainable materials from low molar mass polyols quickly and at high resolution. The 3D printing of these functional materials may help to expedite the production of sustainable plastics and elastomers with potential to replace conventional petrochemical-based options., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)- Published
- 2024
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33. Childhood Gender Diversity and Mental Health: Protocol for the Longitudinal, Observational Gender Journey Project.
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Hidalgo MA, Chen D, Tishelman AC, Olson-Kennedy J, Chan YM, Garofalo R, Petras H, Rosenthal SM, and Ehrensaft D
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- Humans, Male, Child, Female, Longitudinal Studies, United States epidemiology, Gender Identity, Gender Dysphoria psychology, Gender Dysphoria therapy, Transgender Persons psychology, Transgender Persons statistics & numerical data, Child, Preschool, Mental Health
- Abstract
Background: Prepubertal transgender, nonbinary, and gender-diverse (TGD) children (ie, those asserting gender identity, expressing gender-role behavior outside of culturally defined norms for their sex registered at birth, or both) are presenting in greater numbers to pediatric gender clinics across the United States and abroad. A large subset of TGD children experiences gender dysphoria, that is, distress that arises from the incongruence between gender identity and sex registered at birth. A lack of consensus exists regarding care for prepubertal TGD children due, in part, to a dearth of empirical research on longitudinal developmental trajectories of gender identity, role behavior, and gender dysphoria (when present)., Objective: The objective of this National Institutes of Health-funded study is to provide evidence to inform clinical care for prepubertal TGD children by establishing a US longitudinal cohort (N=248) of prepubertal TGD children and their caregivers that is followed prospectively at 6-month intervals across 18 months., Methods: At each timepoint, clinical and behavioral data are collected via web-based visit from child and caregiver reporters. Latent class analysis, among other methods, is used to identify subgroups and longitudinally characterize the gender identity and gender-role behavior of TGD children. These models will define longitudinal patterns of gender identity stability and characterize the relationship between TGD classes and mental and behavioral health outcomes, including the moderating role of social gender transition (when present), on these associations., Results: Baseline data collection (N=248) is complete, and the identification of TGD subgroups based on gender identity and expression using latent class analysis is anticipated in 2024. The completion of all 4 waves of data collection is anticipated in July 2024, coinciding with the start of a no-cost study extension period. We anticipate longitudinal analyses to be completed by winter 2024., Conclusions: Through a longitudinal observational design, this research involving prepubertal TGD children and their caregivers aims to provide empirical knowledge on gender development in a US sample of TGD children, their mental health symptomology and functioning over time, and how family initiated social gender transition may predict or alleviate mental health symptoms or diagnoses. The research findings have promise for clinicians and families aiming to ensure the best developmental outcome for these children as they develop into adolescents., International Registered Report Identifier (irrid): DERR1-10.2196/55558., (©Marco A Hidalgo, Diane Chen, Amy C Tishelman, Johanna Olson-Kennedy, Yee-Ming Chan, Robert Garofalo, Hanno Petras, Stephen M Rosenthal, Diane Ehrensaft. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 09.08.2024.)
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- 2024
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34. Healthcare communication satisfaction and psychosocial outcomes in adolescents and young adults with differences of sex development.
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Liles SM, Crerand CE, Buchanan C, Chan YM, Chen D, Hansen-Moore J, Tishelman AC, Umbaugh H, and Nahata L
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- Humans, Adolescent, Female, Male, Young Adult, Adult, Disorders of Sex Development psychology, Child, Adaptation, Psychological, Surveys and Questionnaires, Resilience, Psychological, Communication, Quality of Life psychology, Patient Satisfaction
- Abstract
Objectives: We examined: (1) healthcare communication satisfaction and psychosocial outcomes (resilience, QoL, and psychological adjustment) in adolescents and young adults (AYA) with differences of sex development (DSD), (2) differences in psychosocial outcomes between those who were highly satisfied and those who were less satisfied, and (3) group differences between adolescents (ages 12-17) and young adults (ages 18-26) regarding associations with healthcare communication and psychosocial outcomes., Methods: AYA with DSD across four study sites reported on satisfaction with healthcare communication and psychosocial outcomes. Analyses included descriptive statistics (aim 1), independent samples t-tests (aim 2), and Pearson's correlations (aim 3)., Results: Participants reported high levels of satisfaction with healthcare communication. Higher healthcare communication satisfaction was associated with greater resilience (p = .01), better QoL (p = .02), and fewer internalizing problems (p = .04). For adolescents, higher healthcare communication satisfaction was associated with better psychosocial outcomes (p values ranging from.01-.04). No significant associations were found in the young adult group., Conclusions: Satisfaction with healthcare communication is related to positive psychosocial outcomes in adolescents with DSD., Practice Implications: These data underscore the importance of optimizing communication with families, engaging AYA in early and ongoing discussions about their care, and including psychosocial providers in DSD care., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2024
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35. Trajectories of illness uncertainty among parents of children with atypical genital appearance due to differences of sex development.
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Traino KA, Ciciolla LM, Perez MN, Chaney JM, Welch G, Baskin LS, Buchanan CL, Chan YM, Cheng EY, Coplen DE, Wisniewski AB, and Mullins LL
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- Humans, Male, Uncertainty, Female, Adult, Child, Preschool, Child, Infant, Disorders of Sex Development psychology, Parents psychology
- Abstract
Objective: The present study aimed to identify distinct trajectories of parental illness uncertainty among parents of children born with atypical genital appearance due to a difference of sex development over the first year following diagnosis. It was hypothesized that four trajectory classes would emerge, including "low stable," "high stable," "decreasing," and "increasing" classes, and that select demographic, familial, and medical factors would predict these classes., Methods: Participants included 56 mothers and 43 fathers of 57 children born with moderate to severe genital atypia. Participants were recruited from eleven specialty clinics across the U.S. Growth mixture modeling (GMM) approaches, controlling for parent dyad clustering, were conducted to examine classes of parental illness uncertainty ratings over time., Results: A three-class GMM was identified as the best-fitting model. The three classes were interpreted as "moderate stable" (56.8%), "low stable" (33.0%), and "declining" (10.3%). Findings suggest possible diagnostic differences across trajectories., Conclusions: Findings highlight the nature of parents' perceptions of ambiguity and uncertainty about their child's diagnosis and treatment the year following their child's birth/diagnosis. Future research is needed to better understand how these trajectories might shift over the course of the child's development. Results support the development of tailored, evidence-based interventions to address coping with uncertainty among families raising a child with chronic health needs., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society of Pediatric Psychology.)
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- 2024
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36. An Unusual Phenomenon of Spontaneously Reversing Nystagmus in Peripheral Vertigo-A Case Report and Literature Review.
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Yeap SYY, Chan YM, Yip CW, and Sim BLH
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Direction-changing nystagmus on positional testing is classically ascribed to a central pathology. We herein report a case of a patient with Benign Paroxysmal Positional Vertigo (BPPV) who demonstrated the unusual phenomenon of spontaneously reversing nystagmus, and discuss the theorised mechanisms with a novel illustration. In left lateral position, our patient's Videonystagmography (VNG) demonstrated an initially fast-phase geotropic nystagmus (leftward-beating, SPV 29°/s) which then paused for 8 s, then spontaneously reversed direction into a slow-phase ageotropic nystagmus (rightward-beating, SPV 7°/s). The rest of the neurootological examination and audiometry were normal. An MRI Brain scan also revealed no intracranial pathology. In subsequent reviews the vertigo resolved after repositioning manoeuvres for Left Horizontal Canal BPPV. With review of existing literature, this case may have exhibited coexistent left canalolithiasis and cupulolithiasis, resulting in simultaneous ampullopetal then ampullofugal forces in a single head position. Other posited theories include that of Endolymphatic Reflux and short-term central adaptation of the Vestibulo-Ocular Reflex. This case highlights a diagnostic challenge the otolaryngologists and neurologists may face with an atypical spontaneously reversing nystagmus in BPPV. However it remains a priority to rule out central pathologies first, and calls for specialists to take care in diagnosing horizontal canal BPPV by observing for a period of latency and spontaneous reversal of nystagmus first, so as to perform the appropriate repositioning manoeuvres. Laryngoscope, 2024., (© 2024 The American Laryngological, Rhinological and Otological Society, Inc.)
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- 2024
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37. Body image and psychosocial outcomes in youth and young adults with differences of sex development: a multi-method study.
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Crerand CE, Shehata A, Umbaugh H, Kapa HM, Hansen-Moore J, Nahata L, Buchanan C, Chen D, Rausch J, Udaipuria S, Jayanthi VR, Chan YM, Pratt KJ, Buschur E, Indyk J, and Tishelman AC
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- Humans, Female, Male, Adolescent, Young Adult, Cross-Sectional Studies, Adult, Resilience, Psychological, Psychosocial Functioning, Body Image psychology, Quality of Life psychology, Disorders of Sex Development psychology
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Objective: Differences of sex development (DSD) can affect the physical health, appearance, and psychosocial functioning of affected individuals, but little is known about how subjective appearance perceptions (body image) impact psychosocial outcomes. This study evaluated body image and its associations with psychosocial outcomes including quality of life, resilience, and psychosocial adjustment., Methods: This cross-sectional, multi-method study assessed body image and psychosocial outcomes including quality of life, adjustment, and resilience in 97 youth and young adults with DSD (mean age = 17 ± 3.7 years; 56% assigned female in infancy) using psychometrically sound instruments. A subsample (n = 40) completed qualitative interviews., Results: Quantitative results indicated that overall, participants were satisfied with their physical appearance, although less so with their primary sex characteristics. Body image dissatisfaction was associated with poorer psychosocial adjustment, quality of life, and resilience. Qualitatively, youth and young adults reported a variety of perceptions, both positive and negative, related to their body image and the impact of living with a DSD condition. Themes identified included appearance management; effects of DSD on body image; diagnostic factors and features; attitudes about diagnosis; and treatment., Conclusions: Body image is significantly associated with psychosocial outcomes in youth and young adults with DSD, with qualitative findings highlighting both positive and negative body image experiences. Results have implications for clinical care including screening for appearance concerns, normalization of appearance variations, and intervention development to better support healthy body image and psychosocial functioning in youth and young adults with DSD., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2024
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38. The impact of long-term care interventions on healthcare utilisation among older persons: a scoping review of reviews.
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Balqis-Ali NZ, Jawahir S, Chan YM, Lim AW, Azlan UW, Shaffie SSM, Fun WH, and Lee SWH
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- Humans, Aged, Aged, 80 and over, Long-Term Care methods, Long-Term Care trends, Patient Acceptance of Health Care
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Background: As the ageing population grows, the demand for long-term care (LTC) services will rise, concurrently amplifying healthcare utilisation. This review aims to examine and consolidate information on LTC interventions that influence healthcare utilisation among older persons., Methods: A scoping review was performed through a systematic search in PubMed, EBSCO CINAHL, EBM Reviews - Cochrane Database of Systematic Reviews, Embase, APA PsycInfo, EBM Reviews - Health Technology Assessment, and EBM Reviews - NHS Economic Evaluation Database. Systematic reviews with meta-analyses published between 1 January 2010 and 2 June 2022 among older persons aged 60 and above were included. The characteristics of LTC interventions were mapped to the World Health Organization (WHO) Healthy Ageing Framework. The effect sizes of healthcare utilisations for LTC interventions were recalculated using a random-effects model. The methodological quality was assessed with the AMSTAR-2 checklist, while the quality of evidence for each association was evaluated using GRADE., Results: Thirty-seven meta-analyses were included. The most prominent domain of the healthy ageing framework was managing chronic conditions. One hundred twelve associations between various LTC interventions and healthcare utilisations were identified, with 22 associations impacting healthcare utilisation. Four interventions were supported by suggestive or convincing evidence. Preventive home visits were found to reduce hospital admission (OR: 0.73, 95% CI: 0.59, 0.91, p = 0.005), caregiver integration during discharge planning (OR: 0.68, 95% CI: 0.57, 0.81, p < 0.001), and continuity of care (OR: 0.76, 95% CI: 0.61, 0.95, p = 0.018) reduced hospital readmission, and perioperative geriatric interventions reduced the length of hospital stay (MD: -1.50, 95% CI: -2.24, -0.76, p < 0.001). None of the associations impacted emergency department visits, medication use, and primary care utilisations with convincing evidence. Most reviews received low methodological quality., Conclusion: The findings suggest that LTC interventions could benefit from transitioning to a community-based setting involving a multidisciplinary team, including carers. The spectrum of services should incorporate a comprehensive assessment to ensure continuous care., (© 2024. The Author(s).)
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- 2024
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39. Clinical Outcomes in Patients With Benign Paroxysmal Positional Vertigo and Vitamin D Deficiency: A Singaporean Perspective.
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Chu C, Chan YM, and Tang J
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Introduction: Benign paroxysmal positional vertigo (BPPV) is the primary vestibular disorder causing peripheral vertigo. Given the role of vitamin D in maintaining otoconia homeostasis, its deficiency may elevate the risk of BPPV. Our study seeks to evaluate the correlation between vitamin D deficiency and clinical outcomes of patients with BPPV in the local Asian population., Methodology: We performed a retrospective analysis of 149 consecutive adult patients referred to a tertiary center's Otolaryngology dizziness clinic between 2018 and 2021. All of these patients had both BPPV and vitamin D deficiency., Results: The mean serum vitamin D level was 19.4 ± 5.5 ng/mol. Approximately 51.7% (77/149) of patients experienced recurrent episodes of BPPV. Univariate Chi-square analyses demonstrated vitamin D levels ( P < 0.001) and history of migraine ( P = 0.04) were related to BPPV recurrence. On multivariate analyses, patients with higher serum vitamin D levels were 16.7% less likely to develop recurrent BPPV (odds ratio [OR] 0.83, 95% confidence interval [CI] 0.76-0.90, P < 0.001). However, migraine history was not significantly related to BPPV recurrence (OR 0.38, 95% CI 0.14-1.00, P = 0.050). There was no statistically significant difference in the duration of BPPV episodes based on vitamin D levels ( P = 0.327)., Conclusions: Patients with vitamin D deficiency are at higher risk of recurrent BPPV. Future research directions that would be beneficial include conducting a randomized controlled trial to evaluate both the effectiveness of vitamin D supplementation and its optimal dosage., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Chu et al.)
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- 2024
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40. A Biomineralized Bifunctional Patient-Friendly Nanosystem for Sustained Glucose Monitoring and Control in Diabetes.
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Yang Z, Chan YM, Chan DS, Wu C, Wang Z, Jiang Y, Liu D, Xia Z, Zhang L, Cai Y, and Wong CY
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Regular blood glucose monitoring and control is necessary for people with type 1 or advanced type 2 diabetes, yet diagnosing and treating patients with diabetes in an accurate, sustained and patient-friendly manner remains limited. Here, a glucose-responsive bifunctional nanosystem (PGOxMns) is constructed via one-pot biomineralisation of manganese dioxide with glucose oxidase and ε-poly-L-lysine. Under hyperglycaemic conditions, the cascade reactions that occur when glucose interacts with PGOxMns can trigger the production of Mn(II), which enhances the magnetic resonance imaging signal. Simultaneously, manganese dioxide catalyses the decomposition of toxic hydrogen peroxide into oxygen, which also maintains glucose oxidase (GOx) activity. In an in vivo model of diabetes, PGOxMns is used to monitor glucose levels (0-20 mm) and allowed identification of diabetic mice via T
1 -weighted MRI. Furthermore, PGOxMns is found to have a high insulin-loading capacity (83.6%), likely due to its positive charge. A single subcutaneous injection of insulin-loaded nanosystem (Ins-PGOxMns) into diabetic mice resulted in a rapid and efficient response to a glucose challenge and prolonged blood glucose level control (< 200 mg dL-1 ) for up to 50 h. Overall, this proof-of-concept study demonstrates the feasibility of using biomineralised nanosystems to develop patient-friendly strategies for glucose monitoring and control., (© 2024 Wiley‐VCH GmbH.)- Published
- 2024
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41. Laboratory Changes During Gender-Affirming Hormone Therapy in Transgender Adolescents.
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Millington K, Lee JY, Olson-Kennedy J, Garofalo R, Rosenthal SM, and Chan YM
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- Humans, Adolescent, Female, Male, Alanine Transaminase blood, Estradiol blood, Hematocrit, Aspartate Aminotransferases blood, Sex Reassignment Procedures, Glycated Hemoglobin analysis, Prolactin blood, Hemoglobins analysis, Transsexualism drug therapy, Hormone Replacement Therapy methods, Transgender Persons, Testosterone blood, Testosterone therapeutic use, Testosterone adverse effects
- Abstract
Objectives: Guidelines for monitoring of medications frequently used in the gender-affirming care of transgender and gender-diverse (TGD) adolescents are based on studies in adults or other medical conditions. In this study, we aimed to investigate commonly screened laboratory measurements in TGD adolescents receiving gender-affirming hormone therapy (GAHT)., Methods: TGD adolescents were recruited from 4 study sites in the United States before beginning GAHT. Hemoglobin, hematocrit, hemoglobin A1c, alanine transaminase, aspartate aminotransferase, prolactin, and potassium were abstracted from the medical record at baseline and at 6, 12, and 24 months after starting GAHT., Results: Two-hundred and ninety-three participants (68% designated female at birth) with no previous history of gonadotropin-releasing hormone analog use were included in the analysis. Hemoglobin and hematocrit decreased in adolescents prescribed estradiol (-1.4 mg/dL and -3.6%, respectively) and increased in adolescents prescribed testosterone (+1.0 mg/dL and +3.9%) by 6 months after GAHT initiation. Thirteen (6.5%) participants prescribed testosterone had hematocrit > 50% during GAHT. There were no differences in hemoglobin A1c, alanine transaminase, or aspartate aminotransferase. There was a small increase in prolactin after 6 months of estradiol therapy in transfeminine adolescents. Hyperkalemia in transfeminine adolescents taking spironolactone was infrequent and transient if present., Conclusions: Abnormal laboratory results are rare in TGD adolescents prescribed GAHT and, if present, occur within 6 months of GAHT initiation. Future guidelines may not require routine screening of these laboratory parameters beyond 6 months of GAHT in otherwise healthy TGD adolescents., (Copyright © 2024 by the American Academy of Pediatrics.)
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- 2024
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42. Improving Understanding of Visual Snow by Quantifying its Appearance and Effect on Vision.
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Brooks CJ, Chan YM, Fielding J, White OB, Badcock DR, and McKendrick AM
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- Humans, Male, Female, Adult, Middle Aged, Young Adult, Sensory Thresholds physiology, Vision Disorders physiopathology, Vision Disorders diagnosis, Aged, Visual Perception physiology, Observer Variation, Pattern Recognition, Visual physiology, Perceptual Disorders, Visual Acuity physiology
- Abstract
Purpose: Visual snow is the hallmark of the neurological condition visual snow syndrome (VSS) but the characteristics of the visual snow percept remain poorly defined. This study aimed to quantify its appearance, interobserver variability, and effect on measured visual performance and self-reported visual quality., Methods: Twenty-three participants with VSS estimated their visual snow dot size, separation, luminance, and flicker rate by matching to a simulation. To assess whether visual snow masks vision, we compared pattern discrimination thresholds for textures that were similar in spatial scale to visual snow as well as more coarse than visual snow, in participants with VSS, and with and without external noise simulating visual snow in 23 controls., Results: Mean and 95% confidence intervals for visual snow appearance were: size (6.0, 5.8-6.3 arcseconds), separation (2.0, 1.7-2.3 arcmin), luminance (72.4, 58.1-86.8 cd/m2), and flicker rate (25.8, 18.9-32.8 frames per image at 120 hertz [Hz]). Participants with finer dot spacing estimates also reported greater visibility of their visual snow (τb = -0.41, 95% confidence interval [CI] = -0.62 to -0.13, P = 0.01). In controls, adding simulated fine-scale visual snow to textures increased thresholds for fine but not coarse textures (F(1, 22) = 4.98, P = 0.036, ηp2 = 0.19). In VSS, thresholds for fine and coarse textures were similar (t(22) = 0.54, P = 0.60), suggesting that inherent visual snow does not act like external noise in controls., Conclusions: Our quantitative estimates of visual snow constrain its likely neural origins, may aid differential diagnosis, and inform future investigations of how it affects vision. Methods to quantify visual snow are needed for evaluation of potential treatments.
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- 2024
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43. Increased Depressive-like, Anxiety-like, and Perseverative-like Behavior in Binge Eating Model in Juvenile Rats.
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Genis-Mendoza AD, Juárez-Rojop IE, Escobar-Chan YM, Tovilla-Zárate CA, López-Narváez ML, Nicolini H, and González-Castro TB
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- Animals, Rats, Male, Stress, Psychological, Binge-Eating Disorder psychology, Rats, Wistar, Anxiety, Depression psychology, Disease Models, Animal, Behavior, Animal, Bulimia psychology, Caloric Restriction
- Abstract
The aim of the present study was to evaluate depressive-like, anxiety-like, and perseverative-like behaviors in a binge eating model. Juvenile Wistar rats, using the binge eating model, were compared to caloric restriction, induced stress, and control groups. Rats of the induced stress group presented binge-like behaviors in standard food intake in the second cycle of the experiment when compared to the caloric restriction group and the binge eating model group. Depressive-like behavior was observed in the binge eating model group with longer immobility time ( p < 0.001) and less swim time ( p < 0.001) in comparison to the control group. Anxiety-like behavior was observed by shorter duration of burying latency in the binge eating model group when compared to the induced stress group ( p = 0.04) and a longer duration of burying time when compared to the control group ( p = 0.02). We observed perseverative-like behavior by the binge model group, who made more entries to the new arm ( p = 0.0004) and spent a longer time in the new arm when compared to the control group ( p = 0.0001). Our results show differences in behaviors between the groups of rats studied. These results suggest that calorie restriction-refeeding, along with stress, may lead to depressive-like, anxiety-like, and perseverative-like behavioral changes in male Wistar rats.
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- 2024
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44. Combined Effect of Dietary Acid Load and Cardiometabolic Syndrome on Bone Resorption Marker among Post-Menopausal Women in Malaysia.
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Lim SY, Chan YM, Chin YS, Zalilah MS, Ramachandran V, and Arumugam M
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Background: This study aimed to investigate factors associated with bone resorption status and determine the independent and interactive effects of dietary acid load (DAL) and cardiometabolic syndrome (CMS) on bone resorption in post-menopausal women., Methods: Overall, 211 community-dwelling post-menopausal women were recruited from the National Council of Senior Citizens Organization, Malaysia. DAL was estimated using the potential renal acid load from the food frequency questionnaire. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and smoking behaviour was assessed using the Global Adult Tobacco Survey 2011. Serum 25(OH) vitamin D levels were determined using the ADVIA Centaur vitamin D assay and serum C-terminal telopeptides of type I collagen (CTX1) were used as surrogate markers to assess bone resorption. CMS was determined based on the harmonised criteria., Results: Age ( β = -0.145, t = -2.002, P < 0.05) was negatively associated while DAL ( β = 0.142, t = 2.096, P < 0.05) and sleep quality ( β = 0.147, t = 2.162, P < 0.05) were positively associated with CTX1. Height was positively correlated with CTX1 ( r = 0.136, P <0.05). Conversely, other variables (CMS traits, CMS, serum 25(OH) vitamin D level, years of menopause, years of education and physical activity) were not significantly associated with CTX1 levels. There was no significant interaction between DAL and CMS on bone resorption., Conclusion: Our findings propose that high DAL, but not CMS, is a potential risk factor for bone resorption. The analysis did not demonstrate the combined effects of DAL and CMS on bone resorption., Competing Interests: Conflict of Interest: None., (© Penerbit Universiti Sains Malaysia, 2024.)
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- 2024
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45. Development of an explainable artificial intelligence model for Asian vascular wound images.
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Lo ZJ, Mak MHW, Liang S, Chan YM, Goh CC, Lai T, Tan A, Thng P, Rodriguez J, Weyde T, and Smit S
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- Humans, Software, Machine Learning, Health Facilities, Artificial Intelligence, Algorithms
- Abstract
Chronic wounds contribute to significant healthcare and economic burden worldwide. Wound assessment remains challenging given its complex and dynamic nature. The use of artificial intelligence (AI) and machine learning methods in wound analysis is promising. Explainable modelling can help its integration and acceptance in healthcare systems. We aim to develop an explainable AI model for analysing vascular wound images among an Asian population. Two thousand nine hundred and fifty-seven wound images from a vascular wound image registry from a tertiary institution in Singapore were utilized. The dataset was split into training, validation and test sets. Wound images were classified into four types (neuroischaemic ulcer [NIU], surgical site infections [SSI], venous leg ulcers [VLU], pressure ulcer [PU]), measured with automatic estimation of width, length and depth and segmented into 18 wound and peri-wound features. Data pre-processing was performed using oversampling and augmentation techniques. Convolutional and deep learning models were utilized for model development. The model was evaluated with accuracy, F1 score and receiver operating characteristic (ROC) curves. Explainability methods were used to interpret AI decision reasoning. A web browser application was developed to demonstrate results of the wound AI model with explainability. After development, the model was tested on additional 15 476 unlabelled images to evaluate effectiveness. After the development on the training and validation dataset, the model performance on unseen labelled images in the test set achieved an AUROC of 0.99 for wound classification with mean accuracy of 95.9%. For wound measurements, the model achieved AUROC of 0.97 with mean accuracy of 85.0% for depth classification, and AUROC of 0.92 with mean accuracy of 87.1% for width and length determination. For wound segmentation, an AUROC of 0.95 and mean accuracy of 87.8% was achieved. Testing on unlabelled images, the model confidence score for wound classification was 82.8% with an explainability score of 60.6%. Confidence score was 87.6% for depth classification with 68.0% explainability score, while width and length measurement obtained 93.0% accuracy score with 76.6% explainability. Confidence score for wound segmentation was 83.9%, while explainability was 72.1%. Using explainable AI models, we have developed an algorithm and application for analysis of vascular wound images from an Asian population with accuracy and explainability. With further development, it can be utilized as a clinical decision support system and integrated into existing healthcare electronic systems., (© 2023 The Authors. International Wound Journal published by Medicalhelplines.com Inc and John Wiley & Sons Ltd.)
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- 2024
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46. Effectiveness of Mediterranean Diet on Daytime Sleepiness among Individuals with Type 2 Diabetes Mellitus in Oman.
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AlAufi NS, Chan YM, Chin YS, Ahmad N, Mohd-Yusof BN, Waly MI, Al Busaidi N, Al-Shuriqi S, Al Amri K, Al Bulushi F, and Al Bulushi S
- Abstract
Background Sleep disturbance is a major complaint among individuals with diabetes mellitus and may be augmented by dietary interventions. The objective of this randomized controlled trial was to determine the effectiveness of a Mediterranean diet intervention on daytime sleepiness among individuals with type 2 diabetes mellitus (T2DM) in Oman. Methods In total, 134 eligible individuals with T2DM (61 and 73 participants in the intervention and control groups, respectively) were recruited. The intervention participants underwent a 6-month Mediterranean diet intervention consisting of individual dietary counseling, cooking classes, phone calls, and social media messages, while the control group continued with standard diabetes care. Daytime sleepiness was assessed using the Epworth Sleepiness Scale. All data was analyzed using IBM SPSS Statistics for Windows, version 26.0 (IBM Corp., Armonk, NY, USA). Results Daytime sleepiness was evident, with ∼ 30% of the participants experiencing it, with no significant difference between control and intervention participants at baseline. There was a significant reduction in daytime sleepiness in both the intervention and control groups after 6 months, with daytime sleepiness significantly lower in the intervention group, with a modest difference of 42.56% ( p < 0.001). Conclusion Adherence to the Mediterranean diet is effective in reducing daytime sleepiness among individuals with T2DM. Clinical Trial UMIN000041152., Competing Interests: Conflict of Interests The authors have no conflict of interests to declare., (Brazilian Sleep Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)
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- 2024
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47. Genome-wide analyses identify 21 infertility loci and over 400 reproductive hormone loci across the allele frequency spectrum.
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Venkatesh SS, Wittemans LBL, Palmer DS, Baya NA, Ferreira T, Hill B, Lassen FH, Parker MJ, Reibe S, Elhakeem A, Banasik K, Bruun MT, Erikstrup C, Jensen BA, Juul A, Mikkelsen C, Nielsen HS, Ostrowski SR, Pedersen OB, Rohde PD, Sorensen E, Ullum H, Westergaard D, Haraldsson A, Holm H, Jonsdottir I, Olafsson I, Steingrimsdottir T, Steinthorsdottir V, Thorleifsson G, Figueredo J, Karjalainen MK, Pasanen A, Jacobs BM, Hubers N, Lippincott M, Fraser A, Lawlor DA, Timpson NJ, Nyegaard M, Stefansson K, Magi R, Laivuori H, van Heel DA, Boomsma DI, Balasubramanian R, Seminara SB, Chan YM, Laisk T, and Lindgren CM
- Abstract
Genome-wide association studies (GWASs) may help inform treatments for infertility, whose causes remain unknown in many cases. Here we present GWAS meta-analyses across six cohorts for male and female infertility in up to 41,200 cases and 687,005 controls. We identified 21 genetic risk loci for infertility ( P ≤5E-08), of which 12 have not been reported for any reproductive condition. We found positive genetic correlations between endometriosis and all-cause female infertility ( r
g =0.585, P =8.98E-14), and between polycystic ovary syndrome and anovulatory infertility ( rg =0.403, P =2.16E-03). The evolutionary persistence of female infertility-risk alleles in EBAG9 may be explained by recent directional selection. We additionally identified up to 269 genetic loci associated with follicle-stimulating hormone (FSH), luteinising hormone, oestradiol, and testosterone through sex-specific GWAS meta-analyses (N=6,095-246,862). While hormone-associated variants near FSHB and ARL14EP colocalised with signals for anovulatory infertility, we found no rg between female infertility and reproductive hormones ( P >0.05). Exome sequencing analyses in the UK Biobank (N=197,340) revealed that women carrying testosterone-lowering rare variants in GPC2 were at higher risk of infertility (OR=2.63, P =1.25E-03). Taken together, our results suggest that while individual genes associated with hormone regulation may be relevant for fertility, there is limited genetic evidence for correlation between reproductive hormones and infertility at the population level. We provide the first comprehensive view of the genetic architecture of infertility across multiple diagnostic criteria in men and women, and characterise its relationship to other health conditions., Competing Interests: Competing Interests Statement L.B.L.W. is currently employed by Novo Nordisk Research Centre Oxford but, while she conducted the research described in this manuscript, was only affiliated to the University of Oxford. V.S., G.T., H.H., I.J., and K.S. are employees of deCODE genetics, a subsidiary of Amgen. C.M.L. reports grants from Bayer AG and Novo Nordisk and has a partner who works at Vertex. The other authors declare no conflicts of interest.- Published
- 2024
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48. A framework for conducting time-varying genome-wide association studies: An application to body mass index across childhood in six multiethnic cohorts.
- Author
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Burrows K, Heiskala A, Bradfield JP, Balkhiyarova Z, Ning L, Boissel M, Chan YM, Froguel P, Bonnefond A, Hakonarson H, Alves AC, Lawlor DA, Kaakinen M, Järvelin MR, Grant SFA, Tilling K, Prokopenko I, Sebert S, Canouil M, and Warrington NM
- Abstract
Genetic effects on changes in human traits over time are understudied and may have important pathophysiological impact. We propose a framework that enables data quality control, implements mixed models to evaluate trajectories of change in traits, and estimates phenotypes to identify age-varying genetic effects in genome-wide association studies (GWASs). Using childhood body mass index (BMI) as an example, we included 71,336 participants from six cohorts and estimated the slope and area under the BMI curve within four time periods (infancy, early childhood, late childhood and adolescence) for each participant, in addition to the age and BMI at the adiposity peak and the adiposity rebound. GWAS on each of the estimated phenotypes identified 28 genome-wide significant variants at 13 loci across the 12 estimated phenotypes, one of which was novel (in DAOA) and had not been previously associated with childhood or adult BMI. Genetic studies of changes in human traits over time could uncover novel biological mechanisms influencing quantitative traits., Competing Interests: Conflict of interest: DAL received support from Medtronic Ltd and Roche Diagnostics for research unrelated to that presented here. All other authors report no conflict of interest.
- Published
- 2024
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49. Contributions of common genetic variants to constitutional delay of puberty and idiopathic hypogonadotropic hypogonadism.
- Author
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Lippincott MF, Schafer EC, Hindman AA, He W, Brauner R, Delaney A, Grinspon R, Hall JE, Hirschhorn JN, McElreavey K, Palmert MR, Rey R, Seminara SB, Salem RM, and Chan YM
- Abstract
Context: Constitutional delay of puberty (CDP) is highly heritable, but the genetic basis for CDP is largely unknown. Idiopathic hypogonadotropic hypogonadism (IHH) can be caused by rare genetic variants, but in about half of cases, no rare-variant cause is found., Objective: To determine whether common genetic variants that influence pubertal timing contribute to CDP and IHH., Design: Case-control study., Participants: 80 individuals with CDP; 301 with normosmic IHH, and 348 with Kallmann syndrome; control genotyping data from unrelated studies., Main Outcome Measures: Polygenic scores (PGS) based on genome-wide association studies for timing of male pubertal hallmarks and age at menarche (AAM)., Results: The CDP cohort had higher PGS for male pubertal hallmarks and for AAM compared to controls (for male hallmarks, Cohen's d = 0.85, p = 1 × 10-16; for AAM, d = 0.67, p = 1 × 10-10). The normosmic IHH cohort also had higher PGS for male hallmarks compared to controls, but the difference was smaller (male hallmarks d = 0.20, p = 0.003; AAM d = 0.10, p = 0.055). No differences were seen for the KS cohort compared to controls (male hallmarks d = 0.04, p = 0.45; AAM d = -0.03, p = 0.86)., Conclusions: Common genetic variants that influence pubertal timing in the general population contribute strongly to the genetics of CDP, weakly to normosmic IHH, and potentially not at all to KS. These findings demonstrate that the common-variant genetics of CDP and normosmic IHH are largely but not entirely distinct., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
- Published
- 2024
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50. Examining the validity of the Delis-Kaplan Executive Function System (D-KEFS) in traumatic brain injury.
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Hacker D, Jones CA, Chan YM, Yasin E, Clowes Z, Belli A, Cooper J, Bose D, Hawkins A, Davies H, and Paton E
- Subjects
- Humans, Neuropsychological Tests, Executive Function physiology, Cognition, Brain Injuries, Traumatic complications, Cognition Disorders etiology, Cognition Disorders complications
- Abstract
This study examines the validity of the Delis-Kaplan Executive Function System (D-KEFS) in a traumatic brain injury (TBI) population compared to participants with orthopaedic injuries and normative controls. The utility of the D-KEFS was examined using a between groups design. One hundred patients with mild uncomplicated to severe TBI were recruited from a consecutive cohort of patients admitted as inpatients to a UK Major Trauma Centre and compared to 823 participants from the D-KEFS normative sample and 26 participants with orthopaedic injuries. Data were filtered for performance validity. Sample discrimination was calculated from D-KEFS subtest scores and derived index scores. Sensitivity to TBI severity was established. The TBI participants performed significantly lower on the D-KEFS Trail Making Test, Colour Word Interference, Colour Word Switching, Letter Fluency and Verbal Fluency Category Switching Total Words Correct. The D-KEFS index scores discriminated between TBI, orthopaedic and normative participants with large and moderate effect sizes, respectively. The D-KEFS demonstrated a dose-response relationship with TBI severity. These effects were robust to differences in premorbid intellectual functioning; however, D-KEFS performance was sensitive to performance on tests of mental processing speed. The use of a D-KEFS index score provides a robust and reliable discrimination of TBI patients from healthy control participants. This discrimination is not accounted for by premorbid intellect or the non-specific effects of trauma. The clinical and conceptual implications of these findings are considered., (© 2023 The British Psychological Society.)
- Published
- 2024
- Full Text
- View/download PDF
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