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Urban green spaces, including parks, plazas, and squares, are essential components of healthy and sustainable cities. These areas play a central role in enhancing the wellbeing of citizens, fostering social interactions, and promoting sustainable urban development. This study investigates the multifaceted benefits of integrating green spaces into urban environments, such as improving physical and mental health, facilitating social engagement, and supporting environmental sustainability. Despite these benefits, the development and maintenance of urban green spaces face significant challenges, including limited suitable land, financial constraints, and inadequate access, which can exclude certain populations from enjoying these green havens. The study examines specific case studies, including Linyi People’s Park, Lanshan Youth Park, and Yumin Park, to highlight the factors contributing to the success or failure of these spaces. It also draws inspiration from international examples like New York City’s High Line and Germany’s Emscher Landscape Park, which have successfully transformed neglected areas into vibrant green oases. The findings underscore the importance of adopting principles of spatial justice, resource management, urban policy revision, and access reform to ensure the equitable distribution and accessibility of urban green spaces. The study concludes with key recommendations for urban planning and public health policy, aiming to enhance the wellbeing of citizens and strengthen the harmonious relationship between urban development and the natural environment. This study explores the multifaceted benefits of urban green spaces, including parks and plazas, highlighting their critical roles in enhancing physical and mental health, fostering social interactions, and promoting environmental sustainability. Through in-depth case studies of Linyi People’s Park, Lanshan Youth Park, and Yumin Park, the research identifies key factors contributing to the success and challenges of these spaces. Innovations in the study include a holistic analysis of green space benefits, a focus on spatial justice for equitable access, and comparative insights from international examples like New York City’s High Line and Germany’s Emscher Landscape Park. The research identifies several gaps, including the need for longitudinal studies on health impacts, understanding socioeconomic and cultural variability in green space use, evaluating the effectiveness of policy interventions, exploring technological integration, assessing environmental and economic trade-offs, and developing models for community engagement and ownership. Addressing these gaps will enhance strategies for integrating green spaces into urban environments, ensuring their benefits are accessible to all citizens.

Summary: Background: Green space is an important part of the human living environment, with many epidemiological studies estimating its impact on human health. However, no study has quantitatively assessed the credibility of the existing evidence, impeding their translations into policy decisions and hindering researchers from identifying new research gaps. This overview aims to evaluate and rank such evidence credibility. Methods: Following the PRISMA guideline, we systematically searched PubMed, Web of Science, and Embase databases for systematic reviews with meta-analyses concerning green spaces and health outcomes published up to January 15, 2024. We categorized the credibility of meta-analytical evidence from interventional studies into four levels (i.e., high, moderate, low, and very low) using the Grading of Recommendation, Assessment, Development and Evaluations framework, based on five domains including risk of bias, inconsistency, indirectness, imprecision, and publication bias. Further, we recalculated all the meta-analyses from observational studies and classified evidence into five levels (i.e., convincing, highly suggestive, suggestive, weak, and non-significant) by considering stringent thresholds for P-values, sample size, robustness, heterogeneity, and testing for biases. Findings: In total, 154 meta-analysed associations (interventional = 44, observational = 110) between green spaces and health outcomes were graded. Among meta-analyses from interventional studies, zero, four (wellbeing, systolic blood pressure, negative affect, and positive affect), 20, and 20 associations between green spaces and health outcomes were graded as high, moderate, low, and very low credibility evidence, respectively. Among meta-analyses from observational studies, one (cardiovascular disease mortality), four (prevalence/incidence of diabetes mellitus, preterm birth, and small for gestational age infant, and all-cause mortality), 12, 22, and 71 associations were categorized as convincing, highly suggestive, suggestive, weak, and non-significant evidence, respectively. Interpretation: The current evidence largely confirms beneficial associations between green spaces and human health. However, only a small subset of these associations can be deemed to have a high or convincing credibility. Hence, future better designed primary studies and meta-analyses are still needed to provide higher quality evidence for informing health promotion strategies. Funding: The National Natural Science Foundation of China of China; the Guangzhou Science and Technology Program; the Guangdong Medical Science and Technology Research Fund; the Research Grant Council of the Hong Kong SAR; and Sino-German mobility program.

Abstract Background Living in higher greenness level community has many benefits for pregnancy outcomes, however, few research have explored the relationship between greenness and spontaneous abortion (SAB). We aimed to analyze relationships between SAB and community greenness in Chinese pregnant women, and further assessed the modifying effects from air pollutants. Methods We studied 90 890 pregnant women from the China Birth Cohort Study from February 2018 to December 2021. We diagnosed SAB by certified obstetricians and gynecologists. The level of exposure to greenness during the first trimester was measured using the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI). Particulate matter ≤ 2.5 μm (PM2.5), nitrogen dioxide (NO2) and ozone (O3) were used as proxies of ambient air pollution. Time-dependent multivariable adjusted Cox proportional hazards models, with gestational weeks as the time scale, were used to analyze the association between SAB and greenness. We additionally performed subgroup analyses stratified by age, urbanicity, research location, season of birth, temperature, humidity and air pollution levels. Results Lower SAB prevalence was related to living in greener places. A 0.1 unit increase in NDVI500m and EVI500m was significantly associated with a 12.3% (95% CI 9.9%, 15.5%) and 16.2% (95% CI 11.4%, 20.6%) lower risks of SAB, respectively. In sensitivity analysis, these relationships remained consistent. The associations were stronger among older, participants lived in the north of China and lived in places with higher PM2.5 and lower NO2 levels. Conclusions Our findings indicate significantly inverse associations between community greenness and SAB in Chinese pregnant women, especially for older and participants who live in the north of China, the PM2.5 and NO2 may modify the effects of greenness on SAB.

Background: Limited evidence exists regarding the link between air pollution exposure and cognitive function in developing countries, particularly in areas with abundant natural sources of particulate matter. Objectives: To investigate this association in a large representative sample of the elderly in northwestern China. Methods: We performed a cross-sectional study among 176,345 participants aged 60–100 years in northwestern China in 2020. A satellite-based spatiotemporal model was applied to assess three-year annual averages of particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM2.5), ≤ 10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3) at residential address. Poor cognitive function was assessed using the Mini-Mental State Examination (MMSE). Generalized linear mixed models were used to assess associations. Results: Compared with participants with the lowest quartiles of PM2.5, PM10, and O3 levels, those with the second, third, and highest quartiles of air pollutants consistently showed increased odds of poor cognitive function and decreased MMSE scores. The odds ratios of poor cognitive function associated with a 10 μg/m3 increment in PM2.5, PM10, and O3 were 1.26 (95 % confidence interval [CI]: 1.17, 1.36), 1.06 (95 %CI: 1.04, 1.08), and 2.76 (95 %CI: 2.11, 3.62), respectively. Subgroup analyses suggested stronger associations between air pollution exposures and poor cognitive function among participants who were younger, were non-Uyghur and were physically active. Conclusion: Long-term exposures to PM2.5, PM10 and O3 were associated with poor cognitive function in elders. Our results suggest that reducing air pollution may alleviate the burden of poor cognitive function in the elderly.

Background: Greenspace is known to have a positive impact on human health and well-being, but its potential effects on visual acuity have not been extensively studied. Objectives: Our aim was to examine the relationship between long-term greenspace exposure and visual acuity in children, while also exploring the potential mechanisms in this association. Methods: We conducted this prospective cohort study based on the Children’s growth environment, lifestyle, physical, and mental health development project (COHERENCE), which screened 286,801 schoolchildren in Guangzhou, China, starting in the 2016/17 academic year and followed them up for three academic years (2017/18-2019/20). Visual acuity was measured using a standardized logarithmic chart, and visual impairment was defined as visual acuity worse than 0.0 logarithm of the minimum angle of resolution (LogMAR) units in the better eye. We used the Normalized Difference Vegetation Index (NDVI), the Soil-Adjusted Vegetation Index (SAVI), and the Enhanced Vegetation Index (EVI) to assess the greenspace surrounding child's geocoded home and school at each visit. Results: Our analysis indicated that higher greenspace exposure was associated with greater visual acuity z-score at baseline and with slower decline in visual acuity z-score during the 3-year follow-up. An interquartile range increase in home-school-based NDVI 300m was associated with a 7% decrease [hazard ratios (HRs): 0.93, 95% confidence interval (CI): 0.92, 0.94] in the risk of visual impairment. We also found that air pollution, physical activity, outdoor time, and recreational screen time partially mediated the greenspace-visual acuity association. Conclusion: Our findings suggest that increasing greenspace exposure could benefit children’s visual acuity development and reduce the risk of visual impairment by reducing air pollution and recreational screen time while increasing physical activity and outdoor time. All results could have potential policy implications, given the individual and societal burdens associated with visual impairment.

Abstract The automatic modulation recognition (AMR) of radar signals has become a popular research topic in recent years. However, most algorithms focus on the type of signal modulation and lack further understanding of the signal. To address this gap, a network architecture for multi‐tasking intra‐pulse description words (MIDW‐Net) is proposed herein. In this framework, the denoising algorithm employs a convolutional denoising autoencoder, which is an effective method for suppressing noise interference and preserving signal information. The multiscale feature‐extraction capability of a feature pyramid network (FPN) is utilized to expand the perceptual domain without losing the high‐frequency features of the image. Finally, AMR and modulation parameter estimation are accomplished via multitask learning. Experiments performed on simulated radar signals using four intra‐pulse descriptors verified the effectiveness of the proposed algorithm.

Abstract Background Hand, foot, and mouth disease (HFMD) is an epidemic infectious disease in China. Relationship of neighborhood greenness with human health has been widely studied, yet its association with severe HFMD has not yet been established. Methods Individual HFMD cases that occurred in Guangdong province in 2010 were recruited and were categorised into mild and severe cases. Residential greenness was assessed using global land cover data. We used a case-control design (i.e., severe versus mild cases) with logistic regression models to assess the association between neighborhood greenness and HFMD severity. Effect modification was also examined. Results A total of 131,606 cases were included, of whom 130,840 were mild cases and 766 were severe cases. In an unadjusted model, HFMD severity increased with higher proportion of neighborhood greenness (odds ratio, OR = 1.029, 95%CI: 1.009–1.050). The greenness-HFMD severity association remained (OR = 1.031, 95%CI: 1.006–1.057) after adjusting for population density, demographic variables and climate variables. Both population density (Z = 4.148, P 5 & ≤7: OR = 1.071, 95%CI: 1.024–1.120; subgroup of > 7: OR = 1.065, 95%CI: 1.034–1.097) on HFMD severity. As to relative humidity, statistically significant association between greenness and HFMD severity was only observed in the subgroup of being lower than and equal to 76% (OR = 1.059, 95%CI: 1.023–1.096). Conclusions Our study found that HFMD severity is associated with the neighborhood greenness in Guangdong, China. This study provides evidence on developing a prevention strategy of discouraging the high-risk groups from going to the crowded green spaces during the epidemic period.

Cylindrical vector beams (CVBs) are the product of polarization modulation of optical fields, and possess both unique focusing characteristics and excellent properties applicable to machining, imaging, communication and other fields. Mode selection couplers comprise a promising new method to realize the long-term stable output of cylindrical vector beam all-fiber lasers. Mode selection couplers have the advantages of a simple structure, high mode conversion efficiency and high mode purity. However, the production process of conventional asymmetric mode selection couplers is more complicated. Therefore, in this paper, a symmetric two-mode coupler with a 1 μm band is designed and fabricated using the finite element method, beam propagation method and fused pull-cone method, and a set of all-fiber passive mode-locked lasers based on symmetric dual-mode couplers are constructed. Finally, we obtain cylindrical vector beam outputs with central wavelengths of 1038.97 nm/1067.72 nm, a repetition rate of 8.78 MHz, pulse durations of 660 ps/656 ps, maximum average powers of 5.25 mW/5.2 mW, and the high mode purity of TM (transverse magnetic)01 mode and TE (transverse electric)01 mode is 97.18% and 97.07%, respectively.

Hollow-core negative-curvature fibres have been the focus of current research, but how to reduce the loss of hollow-core negative-curvature fibres is a serious problem. This paper proposes a new structure of hollow-core negative-curvature fibres, that is numerically simulated using the finite-element method, and compared with the simulation results of hollow-core conjoined-tube negative curvature fibres (CTNCFs) and hollow-core nested anti-resonant nodeless fibres (NANFs). The results show that, the LP01 mode loss can reach 0.003694 dB/km with a transmission wavelength of 1.06 μm, the LP11 mode loss can be as low as 0.28423 dB/km, and the bending loss is 0.4405 dB/km with a bending radius of 5 cm and a transmission wavelength of 1.06 μm. The loss is reduced by an order of magnitude compared to CTNCFs and NANFs.

Ilaria Bertocchi et al. use a mouse model of Grin2a dysfunction to show that activity-independent NMDA receptors are involved in audiogenic seizure generation. Their results suggest a role for NMDA receptors in maintaining an appropriate response to sensory stimuli and a potential mechanism for disease phenotypes in epilepsy patients with GRIN2A mutations.

ObjectiveBased on the respiratory disease big data platform in southern Xinjiang, we established a model that predicted and diagnosed chronic obstructive pulmonary disease, bronchiectasis, pulmonary embolism and pulmonary tuberculosis, and provided assistance for primary physicians.MethodsThe method combined convolutional neural network (CNN) and long-short-term memory network (LSTM) for prediction and diagnosis of respiratory diseases. We collected the medical records of inpatients in the respiratory department, including: chief complaint, history of present illness, and chest computed tomography. Pre-processing of clinical records with “jieba” word segmentation module, and the Bidirectional Encoder Representation from Transformers (BERT) model was used to perform word vectorization on the text. The partial and total information of the fused feature set was encoded by convolutional layers, while LSTM layers decoded the encoded information.ResultsThe precisions of traditional machine-learning, deep-learning methods and our proposed method were 0.6, 0.81, 0.89, and F1 scores were 0.6, 0.81, 0.88, respectively.ConclusionCompared with traditional machine learning and deep-learning methods that our proposed method had a significantly higher performance, and provided precise identification of respiratory disease.

Abstract Background Ubiquitously distributed benzene is a known hematotoxin. Increasing evidence has suggested that erythroid-related hematologic parameters may be sensitive to benzene exposure. Fat content, which is also closely associated with erythroid-related hematologic parameters, may affect the distribution and/or metabolism of benzene, and eventually benzene-induced toxicity. Methods To explore the influence of benzene exposure, fat content, and their interactions on erythroid-related hematologic parameters, we recruited 1669 petrochemical workers and measured their urinary S-phenylmercapturic acid (SPMA) concentration and erythroid-related hematological parameters. Indices for fat content included body fat percentage (BF%), plasma total cholesterol (TC) and triglycerides (TG), and occurrence of fatty liver. Results The dose-response curve revealed U-shaped nonlinear relationships of SPMA with hematocrit (HCT) and mean corpuscular hemoglobin concentration (MCHC) (P-overall

We developed a high-power, double-intracavity-frequency, diode-side-pumped, Q-switched Nd:YAG laser. The thermal birefringence effect of Nd:YAG crystal was compensated by a quartz rotating mirror, and the stable cavity structure was designed according to the thermal focal length of a single module. A 532 nm laser with a maximum linearly polarized output power of 96 W was obtained at a pumping power of 1300 W and repetition rate of 10 kHz. The pulse width was 55.8 ns, and the beam quality was measured to be M2x = 5.98, M2y = 8.14 at the maximum output power; therefore, a brightness as high as 6.97 × 108 W·cm−2·Sr was achieved. To the best of our knowledge, this is the highest brightness obtained for a high-power Nd:YAG laser at 532 nm.

The removal of enoxacin (ENO), a broad-spectrum fluoroquinolone antibiotic, was firstly examined in a sulfate-reducing up-flow sludge bed (SRUSB) bioreactor over a long-term operation (366 days). Over 94% of the ENO was removed in the SRUSB bioreactor via adsorption and biodegradation at different initial ENO concentrations (i.e., 25–1000 μg/L). Based on the results of the batch tests, the sulfate-reducing sludge exhibited a high ENO adsorption capacity within a kd of 22.7–28.9 L/g-SS. The adsorption of ENO by the sulfate-reducing sludge was a spontaneous (ΔG° < 0 KJ/mol) and exothermic (ΔH° < 0 KJ/mol) process including physisorption and chemisorption (absolute value of ΔH° = 51.882 KJ/mol). Moreover, ENO was effectively biodegraded by the sulfate-reducing sludge within specific rates of 2.5–161.3 μg/g-SS/d. The ENO biodegradation process in the sulfate-reducing sludge system was most accurately described by the first-order kinetic model. Collectively, our findings provide insight into the applicability of a sulfate-reducing sludge system for ENO-contaminated wastewater treatment.

Introduction The perinatal–postnatal family environment is associated with childhood outcomes including impacts on physical and mental health and educational attainment. Family longitudinal cohort studies collect in-depth data that can capture the influence of an era on family lifestyle, mental health, chronic disease, education and financial stability to enable identification of gaps in society and provide the evidence for changes in government in policy and practice.Methods and analysis The Queensland Family Cohort (QFC) is a prospective, observational, longitudinal study that will recruit 12 500 pregnant families across the state of Queensland (QLD), Australia and intends to follow-up families and children for three decades. To identify the immediate and future health requirements of the QLD population; pregnant participants and their partners will be enrolled by 24 weeks of gestation and followed up at 24, 28 and 36 weeks of gestation, during delivery, on-ward, 6 weeks postpartum and then every 12 months where questionnaires, biological samples and physical measures will be collected from parents and children. To examine the impact of environmental exposures on families, data related to environmental pollution, household pollution and employment exposures will be linked to pregnancy and health outcomes. Where feasible, data linkage of state and federal government databases will be used to follow the participants long term. Biological samples will be stored long term for future discoveries of biomarkers of health and disease.Ethics and dissemination Ethical approval has been obtained from the Mater Research Ethics (HREC/16/MHS/113). Findings will be reported to (1) QFC participating families; (2) funding bodies, institutes and hospitals supporting the QFC; (3) federal, state and local governments to inform policy; (4) presented at local, national and international conferences and (5) disseminated by peer-review publications.

Background: Epidemiological studies on the association of residential greenness with sleep quality are limited in China. Objective: This study aims to investigate the association of long-term exposure to residential greenness with sleep quality in rural China. Methods: In our study, 27,654 rural residents were selected from 4 counties of Henan Province by a multi-stage stratified cluster sampling method. Participants’ sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). The Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), two satellite-derived vegetation indexes, were used to assess the level of residential greenness. Long-term greenness exposure was defined as the averages of NDVI and EVI during the three years prior to the baseline survey. The relationship between sleep quality and greenness was assessed using the mixed-effect linear regression models. Results: Among 27,654 rural residents, the mean age was 55.89 years (standard deviation, SD = 12.22) and 60.18% of them were female. In the crude model, the PSQI score decreased with per interquartile range (IQR) increase in EVI and NDVI [ΔPSQI score (95% confidence interval, 95%CI): −0.073 (−0.115, −0.030) and −0.047 (−0.089, −0.002)]. After controlling potential confounders, ΔPSQI scores and 95%CIs were −0.055 (−0.095, −0.012) and −0.090 (−0.151, −0.025) associated with per IQR increment in EVI and NDVI. The results of stratified analyses showed the effect of residential greenness on sleep was stronger among males and individuals with higher household income and educational attainment than females and those with lower household income and educational attainment. Moreover, the modification effect of air pollution was observed in the greenness-sleep association. Conclusions: Our study indicated that higher residential greenness was significantly associated with better sleep quality in Chinese rural population, which highlights the significant effect of green space on human health.

Summary: Background: Depression and anxiety are top contributors to non-fatal health loss globally. Several studies have indicated the association between residential greenness and mental health. Method: The participants (n = 27,366) were recruited from four counties in Henan Province, China during 2015–2017. Symptoms of depression and anxiety were evaluated using the Patient Health Questionnaire-2 (PHQ-2) and the Generalized Anxiety Disorder-2 (GAD-2) in the baseline survey. The level of residential greenness during the 3-year period before the baseline survey was assessed using the Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI). The mixed-effect linear regression model was applied to examine the associations of residential greenness with depression and anxiety. Results: The results of adjusted models showed that the score of PHQ-2 (Δscore and 95% confidence interval [CI]) decreased by −0.024 (−0.041, −0.006) and −0.022 (−0.038, −0.004) with an interquartile range (IQR) increase in NDVI and EVI within a 1,000-m buffer radius, respectively. The score of GAD-2 (Δscore and 95% CI) decreased by −0.024 (−0.040, −0.006) and −0.028 (−0.044, −0.011), in relation to an IQR increase in NDVI and EVI within a 1,000-m buffer radius, respectively. Conclusions: A higher level of residential greenness was significantly associated with lower risk of depression and anxiety in rural areas of Henan Province. Improving residential greenness accessibility may help to promote the mental health of rural populations.

Background: Proximity to greenness has shown protective effects on coronary heart diseases by limiting exposure to environmental hazards, encouraging physical activity, and reducing mental stress. However, no studies have previously evaluated the impacts of greenness on congenital heart defects (CHDs). We examined the association between maternal residential greenness and the risks of CHDs. Methods: We conducted a case-control study (8042 children with major CHDs and 6887 controls without malformations) in 21 cities in Southern China, 2004 – 2016. CHDs cases were diagnosed and verified by obstetrician, pediatrician, or pediatric cardiologists, within one year. We estimated maternal residential greenness using satellite-derived normalized difference vegetation index (NDVI) in zones of 500 meters (m) and 1000 m surrounding participants’ residences. Logistic regression models were used to assess NDVI-CHD relationships adjusting for confounders. Results: Interquartile range NDVI increases within 500 m or 1000 m were associated with odds ratios (OR) of 0.95 (95% confidence interval (CI): 0.92, 0.98) and 0.94 (95%CI: 0.91, 0.97) for total CHDs respectively. Air pollutants mediated 52.1% of the association. We also identified a protective threshold at 0.21 NDVI on CHD. Similar protective effects from greenness were found in most CHDs subtypes. The protective associations were stronger for fall, urban or permanent residents, higher household income maternal age ≤35 years of age, and high maternal education (ORs: ranged from 0.85 to 0.96). Conclusion: Our findings suggest a beneficial effect of maternal residential greenness on CHDs. Further studies are needed to confirm our findings, which will help to refine preventive health and urban design strategies.

Abstract Although several studies have investigated the associations of neck circumference (NC) with arterial blood pressures (BPs) and hypertension, no such studies have been conducted among Northern Chinese population. Between April and June 2015, a total of 2631 subjects aged ≥35 years old were recruited from Northeastern China. NC and arterial BPs were measured by trained personnel. Generalized linear and logistic regression analyses were applied to examine the associations of NC with arterial BPs and hypertension risk. The optimal cut-off points of NC for predicting hypertension were assessed by the receiver operating characteristic analysis. We found that NC was significantly associated with arterial BPs and hypertension risk in the Northeastern Chinese adults, even after adjusting for many covariates including body mass index, waist circumference or waist-to-hip ratio. The optimal cut-off values for NC to predict hypertension differed with sex, age, and body mass index. Our study suggests that NC may play an independent role in predicting hypertension beyond the classical anthropometric indices, and that it could be used as a valuable anthropometric measurement for routine assessment in primary care clinics and future epidemiological studies.

A Correction to this paper has been published: https://doi.org/10.1038/s42003-021-01717-x

Hyperhomocysteinemia (HHcy, total homocysteine concentrations > 15 μmol/L) has been associated with increased risk of many diseases. A systematic review was performed to summarize the prevalence of HHcy in China. We searched multiple international and Chinese scientific databases for relevant literature, and further manually screened reference lists and corresponded with original authors. Pooled prevalence of HHcy was calculated using random effects model. Subgroup analysis, meta-regression and sensitivity analysis were also performed. A total of 36 studies consisting 60,754 subjects (57.3% male; age range, 3–97 years) were finally included. The overall pooled prevalence of HHcy was 27.5%. Geographically, the prevalence was high in north areas, intermediate in central areas, and low in south areas, and was higher in inland versus coastal areas. The prevalence increased with age and was significantly higher in men than in women. Rural residents had a slightly higher HHcy prevalence than urban residents, and the studies conducted during 2006 to 2012 presented a higher HHcy prevalence than those during 1990 to 2005. In summary, the prevalence of HHcy in China is high, particularly in northern populations, the inlanders, males, and the elderly. Homocysteine-lowering strategies are necessary to reduce this highly preventable disorder.

Prior evidence indicates that homocysteine plays a role in the development of metabolic syndrome (MetS). Methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms are common genetic determinants of homocysteine levels. To investigate the associations of the MTHFR C677T and MTRR A66G polymorphisms with MetS, 692 Chinese Han subjects with MetS and 878 controls were recruited. The component traits of MetS and the MTHFR C677T and MTRR A66G genotypes were determined. A significant association was observed between the MTHFR 677T allele and increased risk of MetS, high fasting blood glucose, high waist circumference, and increasing number of MetS components. The MTRR A66G polymorphism was associated with an increased risk of MetS when combined with the MTHFR 677TT genotype, although there was no association found between MetS and MTRR A66G alone. Furthermore, the MTRR 66GG genotype was associated with high fasting blood glucose and triglycerides. Our data suggest that the MTHFR 677T allele may contribute to an increased risk of MetS in the northern Chinese Han population. The MTRR A66G polymorphism is not associated with MetS. However, it may exacerbate the effect of the MTHFR C677T variant alone. Further large prospective population-based studies are required to confirm our findings.

Several epidemiological studies have investigated the associations of methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms with hypertension (H) or hypertension in pregnancy (HIP). However, the results were controversial. We therefore performed a comprehensive meta-analysis to provide empirical evidences on the associations.The English and Chinese databases were systematically searched to identify relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations. Meta-regression, subgroup analysis, sensitivity analysis, cumulative meta-analysis and assessment of publication bias were performed in our study.A total of 114 studies with 15411 cases and 21970 controls were included, 111 studies with 15094 cases and 21633 controls for the C677T polymorphism and 21 with 2533 cases and 2976 controls for the A1298C polymorphism. Overall, the C677T polymorphism was significantly associated with H and HIP (H & HIP: OR = 1.26, 95% CI = 1.17-1.34; H: OR = 1.36, 95% CI = 1.20-1.53; HIP: OR = 1.21, 95% CI = 1.08-1.32). Stratified analysis by ethnicity revealed a significant association among East Asians and Caucasians, but not among Latinos, Black Africans, and Indians and Sri Lankans. In the stratified analyses according to source of controls, genotyping method, sample size and study quality, significant associations were observed in all the subgroups, with the exception of population based subgroup in H studies and large sample size and "others" genotyping method subgroups in HIP studies. For the A1298C polymorphism, no significant association was observed either in overall or subgroup analysis under all genetic models.This meta-analysis suggests that the MTHFR C677T rather than A1298C polymorphism may be associated with H & HIP, especially among East Asians and Caucasians.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) C677T, A1298C and methionine synthase reductase (MTRR) A66G polymorphisms are important genetic determinants for homocysteine (Hcy) levels, and are associated with several disorders. These polymorphisms are heterogeneously distributed worldwide. Our objective was to explore the geographical distributions of these polymorphisms in China. METHODOLOGIES: 15357 healthy adults were recruited from 10 regions. Buccal samples were collected and genomic DNA was isolated. Genotyping was performed using the fluorogenic 5'-nuclease assay. PRINCIPAL FINDINGS: The prevalence of the three polymorphisms among different populations from China varied significantly and showed apparent geographical gradients. For MTHFR C677T, the frequencies of the 677T allele and the 677TT genotype were significantly higher among northern populations and ranged from the lowest values (24.0% and 6.4%, respectively) in Hainan (southern) to the highest values (63.1% and 40.8%, respectively) in Shandong (northern). For MTHFR A1298C, the 1298C allele and the 1298CC genotype frequencies were significantly higher among southern populations and increased from low values (13.1% and 1.4%, respectively) in Shandong to high values (25.7% and 6.7%, respectively) in Hainan. For A66G, the 66G allele and the 66GG genotype frequencies increased from lower values (23.7% and 5.4%, respectively) in Shandong to higher values (29.2% and 8.6%, respectively) in Hainan. The overall frequency of the 677T allele, 677TT genotype, 1298C allele, 1298CC genotype, 66G allele and 66GG genotype in the Chinese Han population was 45.2%, 23.2%, 18.6%, 3.9%, 25.7%, and 6.6%, respectively. No gender differences were found in the prevalence of both the MTHFR C677T and MTRR A66G polymorphisms. CONCLUSIONS: This study indicates that there are marked geographical variations in the prevalence of the three polymorphisms among Chinese Han populations. Our baseline data may be useful for future researches in related fields.