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BACKGROUND: Evidence suggested that abiotic airborne exposures may be associated with changes in body composition. However, more evidence is needed to identify key pollutants linked to adverse health effects and their underlying biomolecular mechanisms, particularly in sensitive older adults. OBJECTIVES: Our research aimed to systematically assess the relationship between abiotic airborne exposures and changes in body composition among healthy older adults, as well as the potential mediating mechanisms through the serum lipidome. METHODS: From September 2018 to January 2019, we conducted a monthly survey among 76 healthy adults (60-69 years old) in the China Biomarkers of Air Pollutant Exposure (BAPE) study, measuring their personal exposures to 632 abiotic airborne pollutions using MicroPEM and the Fresh Air wristband, 18 body composition indicators from the InBody 770 device, and lipidomics from venous blood samples. We used an exposome-wide association study (ExWAS) and deletion/substitution/addition (DSA) model to unravel complex associations between exposure to contaminant mixtures and body composition, a Bayesian kernel machine regression (BKMR) model to assess the overall effect of key exposures on body composition, and mediation analysis to identify lipid intermediators. RESULTS: The ExWAS and DSA model identified that 2,4,5-T methyl ester (2,4,5-TME), 9,10-Anthracenedione (ATQ), 4b,8-dimethyl-2-isopropyl-phenanthrene, and 4b,5,6,7,8,8a,9,10-octahydro-(DMIP) were associated with increased body fat mass (BFM), fat mass indicators (FMI), percent body fat (PBF), and visceral fat area (VFA) in healthy older adults [Bonferroni-Hochberg false discovery rate ([FDR.sub.BH]) < 0.05]. The BKMR model demonstrated a positive correlation between contaminants (anthracene, ATQ, copaene, di-epi-a-cedrene, and DMIP) with VFA. Mediation analysis revealed that phosphatidylcholine [PC, PC(16:1e/18:1), PC(16:2e/18:0)] and sphingolipid [SM, SM(d18:2/24.1)] mediated a significant portion, ranging from 12.27% to 26.03% (p-value DISCUSSION: Based on the evidence from multiple model results, ATQ and DMIP were statistically significantly associated with the increased VFA levels of healthy older adults, potentially regulated through lipid intermediators. These findings may have important implications for identifying potentially harmful environmental chemicals and developing targeted strategies for the control and prevention of chronic diseases in the future, particularly as the global population is rapidly aging. https://doi.org/10.1289/EHP13865, Introduction The global population is currently undergoing a notable aging trend, primarily driven by declining fertility rates and increased life expectancy. (1) This demographic shift is evident as the number [...]

BACKGROUND: Per- and polyfluoroalkyl Substances (PFAS) are synthetic chemicals widely detected in humans and the environment. Exposure to perfluorooctanesulfonic acid (PFOS) or perfluorohexanesulfonic acid (PFHxS) was previously shown to cause dark-phase hyperactivity in larval zebrafish. OBJECTIVES: The objective of this study was to elucidate the mechanism by which PFOS or PFHxS exposure caused hyperactivity in larval zebrafish. METHODS: Swimming behavior was assessed in 5-d postfertilization (dpf) larvae following developmental (1-4 dpf) or acute (5 dpf) exposure to 0.43-7.86 [micro]M PFOS, 7.87-120 [micro]M PFHxS, or 0.4% dimethyl sulfoxide (DMSO). After developmental exposure and chemical washout at 4 dpf, behavior was also assessed at 5-8 dpf. RNA sequencing was used to identify differences in global gene expression to perform transcriptomic benchmark concentration--response ([BMC.sub.T]) modeling, and predict upstream regulators in PFOS- or PFHxS-exposed larvae. CRISPR/Cas9-based gene editing was used to knockdown peroxisome proliferator-activated receptors (ppars) pparaa/ab, pparda/db, or pparg at day 0. Knockdown crispants were exposed to 7.86 [micro]M PFOS or 0.4% DMSO from 1-4 dpf and behavior was assessed at 5 dpf. Coexposure with the ppard antagonist GSK3787 and PFOS was also performed. RESULTS: Transient dark-phase hyperactivity occurred following developmental or acute exposure to PFOS or PFHxS, relative to the DMSO control. In contrast, visual startle response (VSR) hyperactivity only occurred following developmental exposure and was irreversible up to 8 dpf. Similar global transcriptomic profiles, [BMC.sub.T] estimates, and enriched functions were observed in PFOS- and PFHxS-exposed larvae, and ppars were identified as putative upstream regulators. Knockdown of pparda/db, but not pparaa/ab or pparg, blunted PFOS-dependent VSR hyperactivity to control levels. This finding was confirmed via antagonism of ppard in PFOS-exposed larvae. DISCUSSION: This work identifies a novel adverse outcome pathway for VSR hyperactivity in larval zebrafish. We demonstrate that developmental, but not acute, exposure to PFOS triggered persistent VSR hyperactivity that required ppard function. https://doi.org/10.1289/EHP13667, Introduction Per- and polyfluoroalkyl substances (PFAS) are a diverse class of synthetic chemicals containing >14,000 unique structures used in industrial manufacturing (US EPA PFASSTRUCTv3, last checked December 2023 (1)). PFAS [...]

BACKGROUND: Accumulating evidence suggests that domestic water hardness is linked to health outcomes, but its association to all-cause and cause-specific cancers warrants investigation. OBJECTIVE: The aim of this study was to investigate the association of domestic hard water with all-cause and cause-specific cancers. METHODS: In the prospective cohort study, a total of 447,996 participants from UK Biobank who were free of cancer at baseline were included and followed up for 16 y. All-cause and 22 common cause-specific cancer diagnoses were ascertained using hospital inpatient records and self-reported data until 30 November 2022. Domestic water hardness, measured by CaC[O.sub.3] concentrations, was obtained from the local water supply companies across England, Scotland, and Wales in 2005. Data were analyzed using Cox proportional hazard models, with adjustments for known measured confounders, including demographic, socioeconomic, clinical, biochemical, lifestyle, and environmental factors. RESULTS: Over a median follow-up of 13.6 y (range: 12.7-14.4 y), 58,028 all-cause cancer events were documented. A U-shaped relationship between domestic water hardness and all-cause cancers was observed (p for nonlinearity 60-120 mg/L), 0.88 (95% CI: 0.84, 0.91) for those exposed to hard water (>120-180 mg/L) and 1.06 (95% CI: 1.04, 1.08) for those exposed to very hard water (>180 mg/L). Additionally, domestic water hardness was associated with 11 of 22 cause-specific cancers, including cancers of the esophagus, stomach, colorectal tract, lung, breast, prostate, and bladder, as well as non-Hodgkin lymphoma, multiple myeloma, malignant melanoma, and hematological malignancies. Moreover, we observed a positive linear relationship between water hardness and bladder cancer. DISCUSSION: Our findings suggest that domestic water hardness was associated with all-cause and multiple cause-specific cancers. Findings from the UK Biobank support a potentially beneficial association between hard water and the incidence of all-cause cancer. However, very hard water may increase the risk of all-cause cancer. https://doi.org/10.1289/EHP13606, Introduction Cancer is a leading cause of mortality worldwide in 2020, nearly 10 million deaths were due to cancer, accounting for approximately one-sixth of all deaths. (1-3) It is projected [...]

BACKGROUND: Maternal cigarette smoking during pregnancy (MSDP) is associated with numerous adverse health outcomes in infants and children with potential lifelong consequences. Negative effects of MSDP on placental DNA methylation (DNAm), placental structure, and function are well established. OBJECTIVE: Our aim was to develop biomarkers of MSDP using DNAm measured in placentas (N =96), collected as part of the Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function double-blind, placebo-controlled randomized clinical trial conducted between 2012 and 2016. We also aimed to develop a digital polymerase chain reaction (PCR) assay for the top ranking cytosine--guanine dinucleotide (CpG) so that large numbers of samples can be screened for exposure at low cost. METHODS: We compared the ability of four machine learning methods [logistic least absolute shrinkage and selection operator (LASSO) regression, logistic elastic net regression, random forest, and gradient boosting machine] to classify MSDP based on placental DNAm signatures. We developed separate models using the complete EPIC array dataset and on the subset of probes also found on the 450K array so that models exist for both platforms. For comparison, we developed a model using CpGs previously associated with MSDP in placenta. For each final model, we used model coefficients and normalized beta values to calculate placental smoking index (PSI) scores for each sample. Final models were validated in two external datasets: the Extremely Low Gestational Age Newborn observational study, N = 426; and the Rhode Island Children's Health Study, N = 237. RESULTS: Logistic LASSO regression demonstrated the highest performance in cross-validation testing with the lowest number of input CpGs. Accuracy was greatest in external datasets when using models developed for the same platform. PSI scores in smokers only (n = 72) were moderately correlated with maternal plasma cotinine levels. One CpG (cg27402634), with the largest coefficient in two models, was measured accurately by digital PCR compared with measurement by EPIC array ([R.sup.2] = 0.98). DISCUSSION: To our knowledge, we have developed the first placental DNAm-based biomarkers of MSDP with broad utility to studies of prenatal disease origins. https://doi.org/10.1289/EHP13838, Introduction Maternal cigarette smoking during pregnancy (MSDP) is associated with increased risk of low birth weight, prematurity, and perinatal mortality. (1-4) MSDP is also associated with greater risk of cardiovascular, [...]

BACKGROUND: Evidence linking gaseous air pollution to late-life brain health is mixed. OBJECTIVE: We explored associations between exposure to gaseous pollutants and brain magnetic resonance imaging (MRI) markers among Atherosclerosis Risk in Communities (ARIC) Study participants, with attention to the influence of exposure estimation method and confounding by site. METHODS: We considered data from 1,665 eligible ARIC participants recruited from four US sites in the period 1987-1989 with valid brain MRI data from Visit 5 (2011-2013). We estimated 10-y (2001-2010) mean carbon monoxide (CO), nitrogen dioxide (N[O.sub.2]), nitrogen oxides (N[O.sub.x]), and 8-and 24-h ozone ([O.sub.3]) concentrations at participant addresses, using multiple exposure estimation methods. We estimated site-specific associations between pollutant exposures and brain MRI outcomes (total and regional volumes; presence of microhemorrhages, infarcts, lacunes, and severe white matter hyperintensities), using adjusted linear and logistic regression models. We compared meta-analytically combined site-specific associations to analyses that did not account for site. RESULTS: Within-site exposure distributions varied across exposure estimation methods. Meta-analytic associations were generally not statistically significant regardless of exposure, outcome, or exposure estimation method; point estimates often suggested associations between higher N[O.sub.2] and N[O.sub.x] and smaller temporal lobe, deep gray, hippocampal, frontal lobe, and Alzheimer disease signature region of interest volumes and between higher CO and smaller temporal and frontal lobe volumes. Analyses that did not account for study site more often yielded significant associations and sometimes different direction of associations. DISCUSSION: Patterns of local variation in estimated air pollution concentrations differ by estimation method. Although we did not find strong evidence supporting impact of gaseous pollutants on brain changes detectable by MRI, point estimates suggested associations between higher exposure to CO, N[O.sub.x], and N[O.sub.2] and smaller regional brain volumes. Analyses of air pollution and dementia-related outcomes that do not adjust for location likely underestimate uncertainty and may be susceptible to confounding bias. https://doi.org/10.1289/EHP13906, Introduction Growing evidence links air pollution to late-life cognitive health. Currently, the strongest evidence supports an effect of particulate matter (PM) air pollution. (1) In comparison with PM, fewer studies [...]

BACKGROUND: Cadmium (Cd) is a highly toxic and widespread environmental oxidative stressor that causes a myriad of health problems, including osteoporosis and bone damage. Although nuclear factor erythroid 2-related factor 2 (NRF2) and its Cap 'n' Collar and basic region Leucine Zipper (CNC-bZIP) family member nuclear factor erythroid 2-related factor 1 (NRF1) coordinate various stress responses by regulating the transcription of a variety of antioxidant and cytoprotective genes, they play distinct roles in bone metabolism and remodeling. However, the precise roles of both transcription factors in bone loss induced by prolonged Cd exposure remain unclear. OBJECTIVES: We aimed to understand the molecular mechanisms underlying Cd-induced bone loss, focusing mainly on the roles of NRF2 and NRF1 in osteoclastogenesis provoked by Cd. METHODS: Male wild-type (WT), global Nrf2-knockout (Nrf[2.sup.-/-]) and myeloid-specific Nrf2 knockout [Nrf2(M)-KO] mice were administered Cd (50 or 100 ppm) via drinking water for 8 or 16 wk, followed by micro-computed tomography, histological analyses, and plasma biochemical testing. Osteoclastogenesis was evaluated using bone marrow-derived osteoclast progenitor cells (BM-OPCs) and RAW 264.7 cells in the presence of Cd (10 or 20 nM) with a combination of genetic and chemical modulations targeting NRF2 and NRF1. RESULTS: Compared with relevant control mice, global Nrf[2.sup.-/-] or Nrf2(M)-KO mice showed exacerbated bone loss and augmented osteoclast activity following exposure to 100ppm Cd in drinking water for up to 16 wk. In vitro osteoclastogenic analyses suggested that Nrf2-deficient BM-OPCs and RAW 264.7 cells responded more robustly to low levels of Cd (up to 20 nM) with regard to osteoclast differentiation compared with WT cells. Further mechanistic studies supported a compensatory up-regulation of long isoform of NRF1 (L-NRF1) and subsequent induction of nuclear factor of activated T cells, cytoplasmic, calcineurin dependent 1 (NFATc1) as the key molecular events in the Nrf2 deficiency-worsened and Cd-provoked osteoclastogenesis. L-Nrf1 silenced (via lentiviral means) Nrf2-knockdown (KD) RAW cells exposed to Cd showed dramatically different NFATc1 and subsequent osteoclastogenesis outcomes compared with the cells of Nrf2-KD alone exposed to Cd, suggesting a mitigating effect of the Nrf1 silencing. In addition, suppression of reactive oxygen species by exogenous antioxidants N-acetyl-L-cysteine (2mM) and mitoquinone mesylate (MitoQ; 0.2 [micro]M) mitigated the L-NRF1-associated effects on NFATc1-driven osteoclastogenesis outcomes in Cd-exposed Nrf2-KD cells. CONCLUSIONS: This in vivo and in vitro study supported the authors' hypothesis that Cd exposure caused bone loss, in which NRF2 and L-NRF1 responded to Cd and osteoclastogenic stimuli in a cooperative, but contradictive, manner to coordinate Nfatc1 expression, osteoclastogenesis and thus bone homeostasis. Our study suggests a novel strategy targeting NRF2 and L-NRF1 to prevent and treat the bone toxicity of Cd. https://doi.org/10.1289/EHP13849, Introduction Cadmium (Cd), a nonessential heavy metal, is considered as one of the most toxic environmental and occupational hazards. (1) Human long-term exposure to Cd, which occurs mainly from consumption [...]

BACKGROUND: The potential health benefits of exposure to vegetation, or greenness, are well documented, but there are few nationwide studies in Brazil, a country facing challenges related to land-use planning, deforestation, and environmental health risks. OBJECTIVES: In this study, we investigated the association between greenness and hospitalizations for cardiorespiratory diseases in Brazil. METHODS: We accessed hospital admissions data from 967,771 postal codes (a total of 26,724,624 admissions) covering Brazil for the period between 2008 and 2018. We used Normalized Difference Vegetation Index (NDVI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to measure greenness at the postal-code level. First, we applied a quasi-Poisson regression model to estimate the association between greenness and hospitalizations for circulatory and respiratory diseases, adjusted for air pollution, weather variables, and area-level socioeconomic status. We stratified the analyzes by sex, age group, health outcome, and Brazilian regions. In the second stage, we performed a meta-analysis to estimate pooled effects across the Brazilian regions. RESULTS: The national meta-analysis for the whole population, incorporating both urban and nonurban areas, showed that higher levels of greenness were associated with a lower risk of hospitalizations for circulatory diseases. An interquartile range (IQR = 0:18) increase in average NDVI was associated with a 17% (95% confidence interval: 8%, 27%) lower risk of cardiovascular admissions. In contrast, there was no association found between greenness and respiratory admissions. When specifically examining urban areas, the results remained consistent with the overall findings. However, the analyses of nonurban areas revealed divergent results, suggesting that higher levels of greenness in rural regions are associated with a lower risk of hospital admissions for both circulatory and respiratory diseases. DISCUSSION: The findings emphasize the importance of prioritizing the preservation and creation of green spaces in urban areas as a means of promoting cardiovascular health in Brazil. https://doi.org/10.1289/EHP13442, Introduction Cardiovascular and respiratory diseases are the leading causes of morbidity and mortality worldwide. (1) In Brazil, these diseases are responsible for a significant number of hospital admissions and deaths. [...]

BACKGROUND: Manganese (Mn) plays a significant role in both human health and global industries. Epidemiological studies of exposed populations demonstrate a dose-dependent association between Mn and neuromotor effects ranging from subclinical effects to a clinically defined syndrome. However, little is known about the relationship between early life Mn biomarkers and adolescent postural balance. OBJECTIVES: This study investigated the associations between childhood and adolescent Mn biomarkers and adolescent postural balance in participants from the longitudinal Marietta Communities Actively Researching Exposures Study (CARES) cohort. METHODS: Participants were recruited into CARES when they were 7-9 y old, and reenrolled at 13-18 years of age. At both time points, participants provided samples of blood, hair, and toenails that were analyzed for blood Mn and lead (Pb), serum cotinine, hair Mn, and toenail Mn. In adolescence, participants completed a postural balance assessment. Greater sway indicates postural instability (harmful effect), whereas lesser sway indicates postural stability (beneficial effect). Multivariable linear regression models were conducted to investigate the associations between childhood and adolescent Mn biomarkers and adolescent postural balance adjusted for age, sex, height--weight ratio, parent/caregiver intelligence quotient, socioeconomic status, blood Pb, and serum cotinine. RESULTS: CARES participants who completed the adolescent postural balance assessment (n=123) were 98% White and 54% female and had a mean age of 16 y (range: 13-18 y). In both childhood and adolescence, higher Mn biomarker concentrations were significantly associated with greater adolescent sway measures. Supplemental analyses revealed sex-specific associations; higher childhood Mn biomarker concentrations were significantly associated with greater sway in females compared with males. DISCUSSION: This study found childhood and adolescent Mn biomarkers were associated with subclinical neuromotor effects in adolescence. This study demonstrates postural balance as a sensitive measure to assess the association between Mn biomarkers and neuromotor function. https://doi.org/10.1289/EHP13381, Introduction Manganese (Mn) is an element that exists ubiquitously in the environment, often in combination with other elements. (1) Mn plays a significant role in both human health and global [...]

BACKGROUND: More frequent and intense exposure to extreme heat conditions poses a serious threat to public health. However, evidence on the association between heat and specific diagnoses of morbidity is still limited. We aimed to comprehensively assess the short-term association between cause-specific hospital admissions and high temperature, including the added effect of temperature variability and heat waves and the effect modification by humidity and air pollution. METHODS: We used data on cause-specific hospital admissions, weather (i.e., temperature and relative humidity), and air pollution [i.e., fine particulate matter with aerodynamic diameter [less than or equal to]2.5 [micro]m ([PM.sub.2.5]), fine particulate matter with aerodynamic diameter [less than or equal to]10 [micro]m ([PM.sub.10]), N[O.sub.2], and ozone ([O.sub.3])] for 48 provinces in mainland Spain and the Balearic Islands between 1 January 2006 and 31 December 2019. The statistical analysis was performed for the summer season (June-September) and consisted of two steps. We first applied quasi-Poisson generalized linear regression models in combination with distributed lag nonlinear models (DLNM) to estimate province-specific temperature--morbidity associations, which were then pooled through multilevel univariate/multivariate random-effect meta-analysis. RESULTS: High temperature had a generalized impact on cause-specific hospitalizations, while the added effect of temperature variability [i.e., diurnal temperature range (DTR)] and heat waves was limited to a reduced number of diagnoses. The strongest impact of heat was observed for metabolic disorders and obesity [relative risk (RR) = 1.978; 95% empirical confidence interval (eCI): 1.772, 2.208], followed by renal failure (1.777; 95% eCI: 1.629, 1.939), urinary tract infection (1.746; 95% eCI: 1.578, 1.933), sepsis (1.543; 95% eCI: 1.387, 1.718), urolithiasis (1.490; 95% eCI: 1.338, 1.658), and poisoning by drugs and nonmedicinal substances (1.470; 95% eCI: 1.298, 1.665). We also found differences by sex (depending on the diagnosis of hospitalization) and age (very young children and the elderly were more at risk). Humidity played a role in the association of heat with hospitalizations from acute bronchitis and bronchiolitis and diseases of the muscular system and connective tissue, which were higher in dry days. Moreover, heat-related effects were exacerbated on high pollution days for metabolic disorders and obesity ([PM.sub.2.5]) and diabetes ([PM.sub.10], [O.sub.3]). DISCUSSION: Short-term exposure to heat was found to be associated with new diagnoses (e.g., metabolic diseases and obesity, blood diseases, acute bronchitis and bronchiolitis, muscular and connective tissue diseases, poisoning by drugs and nonmedicinal substances, complications of surgical and medical care, and symptoms, signs, and ill-defined conditions) and previously identified diagnoses of hospital admissions. The characterization of the vulnerability to heat can help improve clinical and public health practices to reduce the health risks posed by a warming planet. https://doi.org/10.1289/EHP13254, Introduction Climate change is increasing the frequency and intensity of exposure to extreme heat conditions, which poses a serious threat to public health globally. (1) In some high-income regions such [...]

If a fresh brain is cut in half, two blue spots can be observed in the brainstem: the locus coeruleus (LC), or "sky-blue place." This bilateral nucleus was first described [...]

Due to the fact that arthrosis is a disease that affects a very large number of people, we felt that presenting some aspects of its pathophysiology and kinetoprophylaxis will be helpful to those working in the field of recovery and beyond. The literature also describes a rather complex clinical picture regarding the processes of degradation and deconditioning of the anatomical joint structures.The presentation of the factors of etiopathogenesis of gonarthrosis and the kinetoprophylactic means of preserving the function of the knee joint is the subject of the study that is intended to be presented. Analysis of the etiopathogenic factors and combating the effects of arthrosis installation through a model of analytical investigation of them, the results obtained from the analysis can be the basis for the realization of a kinetoprophylaxis program.

Background: Vaccination is now considered the most effective measure to prevent the harm resulting from the SARS-CoV-2. Mass vaccination has been started in different regions of the world, including Bangladesh. Objective: The present work has been done to discover the Bangladeshi people's attitude, perception towards COVID-19 vaccines, and their willingness to be vaccinated. Methodology: This crosssectional analysis was performed from the online survey data collected from 01 August 2021 to 17 august 2021 from Bangladeshi people over 21 years old at the Department of Pharmacy, Northern University Bangladesh. Results: Among the total participants (517), the majority (60.74%) gave a positive response for being vaccinated. The reasons for unwillingness to be vaccinated were listed as adverse effects of the vaccine (46.04%), complex procedures of vaccination (18.32%), doubtfulness about the vaccine's efficacy (15.35%), reduced risk perception about COVID-19 (15.35%) and needle phobia (4.95%). Conclusion: It is revealed from the current study that education and media can motivate a person's attitude towards vaccination. To bring mass people under the vaccination program, it is necessary to broadcast proper and authentic information about vaccines. Besides, the procedure of getting vaccines should be simpler. [ABSTRACT FROM AUTHOR]

Background: Tea is one of the most commonly consumed beverages. The main varieties of tea are black tea, green tea, and oolong tea produced from Camellia sinensis plant. Objective: The purpose of this study was to determine fluoride (F) and other elements in commercially available black and herbal tea products and to evaluate their benefits and safety. Methods: Chinese and Indian black teas and herbal tea (in bags or loose) were purchased from Hong Kong supermarkets. The tea infusion was prepared by adding 1 g of tea leaves to 100 mL of deionized water preheated to 85℃. Samples were taken at regular intervals and analyzed for F, using the F− electrode. Trace elements in tea infusion was assessed using atomic absorption spectrophotometry. Results: F concentrations in infused 15 brands of Chinese tea ranged from 0.78 to 3.46 ppm (mg/L), with a mean of 1.73 ± 0.73 standard deviations (SD). The corresponding values for 11 Indian teas ranged from 0.73 to 1.91, with a mean of 1.24 ± 0.32. In six herbal teas, the F concentration is almost negligible. The total F content in tea leaves ranged from 82 to 371 mg/kg. From 5 to 15 min of brewing, the mean (±SD) F released was 83.6% ± 12.1% of the total F in the leaves. Conclusions: Tea is a homogeneous, complex solution of bioactive organic and inorganic ingredients that benefits oral and systemic health. It has a higher F content than any other plant. Drinking tea in moderation, F is unlikely to cause a dental fluorosis on its own, but it can significantly increase daily F intake. The safety of trace elements in tea is less than factor 1 (i.e., the allowable limit). [ABSTRACT FROM AUTHOR]

Background: Tea is one of the most commonly consumed beverages. The main varieties of tea are black tea, green tea, and oolong tea produced from Camellia sinensis plant. Objective: The purpose of this study was to determine fluoride (F) and other elements in commercially available black and herbal tea products and to evaluate their benefits and safety. Methods: Chinese and Indian black teas and herbal tea (in bags or loose) were purchased from Hong Kong supermarkets. The tea infusion was prepared by adding 1 g of tea leaves to 100 mL of deionized water preheated to 85℃. Samples were taken at regular intervals and analyzed for F, using the F− electrode. Trace elements in tea infusion was assessed using atomic absorption spectrophotometry. Results: F concentrations in infused 15 brands of Chinese tea ranged from 0.78 to 3.46 ppm (mg/L), with a mean of 1.73 ± 0.73 standard deviations (SD). The corresponding values for 11 Indian teas ranged from 0.73 to 1.91, with a mean of 1.24 ± 0.32. In six herbal teas, the F concentration is almost negligible. The total F content in tea leaves ranged from 82 to 371 mg/kg. From 5 to 15 min of brewing, the mean (±SD) F released was 83.6% ± 12.1% of the total F in the leaves. Conclusions: Tea is a homogeneous, complex solution of bioactive organic and inorganic ingredients that benefits oral and systemic health. It has a higher F content than any other plant. Drinking tea in moderation, F is unlikely to cause a dental fluorosis on its own, but it can significantly increase daily F intake. The safety of trace elements in tea is less than factor 1 (i.e., the allowable limit).

Qualitative longitudinal research is a useful method for studying adolescent development, not least because the dimension of temporality in the analysis of longitudinal studies can help researchers understand the complexity of transitions during this unique and dynamic life stage. The Gender and Adolescence: Global Evidence programme is a multi-year cross-country longitudinal study of adolescents in low- and middle-income countries. This article presents the methodological opportunities and challenges involved in analyzing such datasets, and seeks to offer insights for researchers undertaking qualitative longitudinal research. To ensure that both breadth and depth of such data are accurately represented in the analysis, a range of analytical approaches can be used. In this article, we provide key examples of how this data has been analyzed across a cohort of adolescent participants, exploring changes both pre- and post-Covid-19 including interactions with critical health and education services, and within individual life histories, exploring individual adolescent trajectories over multiple time points. Furthermore, we highlight how including caregivers' and key informants' perspectives can enhance triangulation of results. We show the importance of using a range of different approaches when analyzing a qualitative longitudinal dataset. [ABSTRACT FROM AUTHOR]

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