Aridity threshold for alpine soil nitrogen isotope signature and ecosystem nitrogen cycling.

Determination of tipping points in nitrogen (N) isotope (δ15N) natural abundance, especially soil δ15N, with increasing aridity, is critical for estimating N-cycling dynamics and N limitation in terrestrial ecosystems. However, whether there are linear or nonlinear responses of soil δ15N to increases in aridity and if these responses correspond well with soil N cycling remains largely unknown. In this study, we investigated soil δ15N and soil N-cycling characteristics in both topsoil and subsoil layers along a drought gradient across a 3000-km transect of drylands on the Qinghai-Tibetan Plateau. We found that the effect of increasing aridity on soil δ15N values shifted from negative to positive with thresholds at aridity index (AI) = 0.27 and 0.29 for the topsoil and subsoil, respectively, although soil N pools and N transformation rates linearly decreased with increasing aridity in both soil layers. Furthermore, we identified markedly different correlations between soil δ15N and soil N-cycling traits above and below the AI thresholds (0.27 and 0.29 for topsoil and subsoil, respectively). Specifically, in wetter regions, soil δ15N positively correlated with most soil N-cycling traits, suggesting that high soil δ15N may result from the "openness" of soil N cycling. Conversely, in drier regions, soil δ15N showed insignificant relationships with soil N-cycling traits and correlated well with factors, such as soil-available phosphorus and foliage δ15N, demonstrating that pathways other than typical soil N cycling may dominate soil δ15N under drier conditions. Overall, these results highlight that different ecosystem N-cycling processes may drive soil δ15N along the aridity gradient, broadening our understanding of N cycling as indicated by soil δ15N under changing drought regimes. The aridity threshold of soil δ15N should be considered in terrestrial N-cycling models when incorporating 15N isotope signals to predict N cycling and availability under climatic dryness.

Nitrogen deposition differentially regulates the sensitivity of gross primary productivity to extreme drought versus wetness.

Global hydroclimatic variability is increasing with more frequent extreme dry and wet years, severely destabilizing terrestrial ecosystem productivity. However, what regulates the consequence of precipitation extremes on productivity remains unclear. Based on a 9-year field manipulation experiment on the Qinghai-Tibetan Plateau, we found that the responses of gross primary productivity (GPP) to extreme drought and wetness were differentially regulated by nitrogen (N) deposition. Over increasing N deposition, extreme dry events reduced GPP more. Among the 12 biotic and abiotic factors examined, this was mostly explained by the increased plant canopy height and proportion of drought-sensitive species under N deposition, making photosynthesis more sensitive to hydraulic stress. While extreme wet events increased GPP, their effect did not shift over N deposition. These site observations were complemented by a global synthesis derived from the GOSIF GPP dataset, which showed that GPP sensitivity to extreme drought was larger in ecosystems with higher N deposition, but GPP sensitivity to extreme wetness did not change with N deposition. Our findings indicate that intensified hydroclimatic variability would lead to a greater loss of land carbon sinks in the context of increasing N deposition, due to that GPP losses during extreme dry years are more pronounced, yet without a synchronous increase in GPP gains during extreme wet years. The study implies that the conservation and management against climate extremes merit particular attention in ecosystems subject to N deposition.

Social support and cognitive activity and their associations with incident cognitive impairment in cognitively normal older adults.

OBJECTIVES: To explore the associations of social support, and cognitive activity with cognitive impairment incidence, and further examine the mediation effect of cognitive activity on the association between social support and cognitive impairment incidence based on a nationwide elderly Chinese cohort. METHODS: We collected the participants from an ongoing cohort of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A total of 9394 older adults aged 65 or more years and free of cognitive impairment who participated in the CLHLS between 2008 and 2018 were included. The information on social support and cognitive activity was collected through a questionnaire. The incident cognitive impairment cases were identified through the Mini-Mental State Examination scale (MMSE). Cox proportional hazard regression models were conducted to calculate the hazard ratios (HRs) and 95% confidence interval (CI) of social support and cognitive activity associated with cognitive impairment. We used casual mediation models to assess the indirect association of cognitive activities underlying the association between social support and cognitive impairment. RESULTS: The adjusted HRs (95% CI) of incident cognitive impairment were 0.956 (0.932 to 0.980), and 0.895 (0.859 to 0.933) associated with per 1 score increase in social support and cognitive activity score, respectively. Better adherence to social support was associated with a higher cognitive activity score (adjusted ß = 0.046, 95% CI[0.032-0.060]). The baseline cognitive activity, as well as the mean cognitive activity at baseline and during the first follow-up wave, mediate the association between social support and the incidence of cognitive impairment, accounting for 11.4% and 12.6% of the total association, respectively. The participants who were aged 80 years or older, or those with mild daily functional limitations gained more benefits in the development of cognitive activity related to social support, leading to a reduction in the risks of cognitive impairment. CONCLUSION: The results of this nationwide cohort provide consistent evidence linking social support, and cognitive activity to reduced risk of subsequent cognitive impairment incidence. These findings provide additional evidence to inform the social strategies to prevent cognitive impairment incidence in elderly people.

Moderating effect of a sodium-rich diet on the association between long-term exposure to fine particulate matter and blood lipids in children and adolescents.

BACKGROUND: Several studies reported that exposure to higher levels of fine particulate matter (PM2.5) was associated with deteriorated lipid profiles in children and adolescents. However, whether a sodium-rich diet could modify the associations remains unknown. We aimed to examine the associations of long-term exposure to PM2.5 with blood lipids in children and adolescents, and further examine the effect modification by dietary and urinary sodium levels based on a multi-community population in China. METHODS: The 3711 study participants were from a cross-sectional study, which interviewed children and adolescents aged 6 to 17 years across Sichuan Province, China between 2015 and 2017. Blood lipid outcomes including blood total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) were assessed. Information on daily dietary sodium consumption was estimated with a semi-quantitative food frequency questionnaire (FFQ), and urinary sodium was used as an internal exposure biomarker. A linear regression model was applied to estimate the associations of prior 2-years' average exposure to ambient PM2.5 with blood lipids. The effect modification by dietary and urinary sodium was examined by stratified analyses. RESULTS: The participants from rural areas had higher levels of daily sodium consumptions. The results of multivariable regression analysis indicated that per 10 µg/m3 incremental change in PM2.5 was associated with a 1.56% (95% confidence interval 0.90%-2.23%) and a 2.26% (1.15%-3.38%) higher blood TC and LDL-C levels, respectively. Among the study participants with higher levels of dietary sodium or urinary sodium, exposure to higher levels of PM2.5 was significantly associated with deteriorated lipid profiles. For example, each 10 µg/m3 incremental change in exposure to PM2.5 was correlated with a 2.83 (-4.65 to -0.97) lower percentage decrease in blood HDL-C levels among the participants who were from the highest quartile of urinary sodium levels. While, these associations changed to be nonsignificant in the participants who were from the lowest quartile of dietary sodium levels. CONCLUSION: Exposure to higher levels of PM2.5 was associated with deteriorated blood lipid levels in children and adolescents. It is noteworthy that these associations might be ameliorated through the adoption of a low-sodium dietary regimen.

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Objective: To explore the risk factors for developing chronic pulmonary heart disease in patients with pneumoconiosis. Methods: The medical records of pneumoconiosis patients admitted to an occupational disease hospital in Sichuan Province between January 2012 and November 2021 were collected. Kaplan-Meier (K-M) method, or product-limit method, was used to plot the incidence curves of pulmonary heart disease in the pneumoconiosis patients. Cox proportional hazard regression model was used to analyze the influencing factors associated with chronic pulmonary heart disease in patients with pneumoconiosis. Results: A total of 885 pneumoconiosis patients were included in this study. The follow-up time was 12 to 115 months and the median follow-up time was 43 months. A total of 138 patients developed chronic pulmonary heart disease and the incidence density of pulmonary heart disease was 38.50/1000 person-years. Multivariate Cox proportional hazard regression analysis showed that the influencing factors of pneumoconiosis inpatients developing chronic pulmonary heart disease included the following, being 50 and older (hazard ratio [HR]=1.85, 95% confidence interval [CI]: 1.25-2.74), stage Ⅲ pneumoconiosis (HR=2.43, 95% CI: 1.48-4.01), resting heart rate≥100 beats/min (HR=2.62, 95% CI: 1.63-4.21), the complication of chronic obstructive pulmonary disease (COPD) (HR=4.52, 95% CI: 2.12-9.63), underweight (HR=2.40, 95% CI: 1.48-3.87), overweight and obesity (HR=0.54, 95% CI: 0.34-0.86), and triacylglycerol (TG) (HR=0.69, 95% CI: 0.49-0.99). Conclusion: Old age, stage Ⅲ pneumoconiosis, high resting heart rate, low BMI, and the complication of COPD are risk factors for chronic pulmonary heart disease in pneumoconiosis patients, while overweight and obesity and TG are protective factors. Early identification of the risk factors and the adoption of the corresponding prevention measures are the key to preventing chronic pulmonary heart disease in patients with pneumoconiosis.

Increases in BMI contribute to worsening inflammatory biomarkers related to breast cancer risk in women: a longitudinal study.

BACKGROUND: Inflammatory adipokines and cytokines play a pivotal role in linking obesity and breast cancer (BC) risk in women. We investigated the longitudinal associations between BMI change and trajectories of inflammatory biomarkers related to BC risk. METHODS: A longitudinal study was conducted among 442 Chinese women with 3-year repeated measures from 2019 to 2021. Plasma circulating inflammatory biomarkers related to BC risk, including adiponectin (ADP), resistin (RETN), soluble leptin receptor (sOB-R), insulin-like growth factor-binding protein-3 (IGFBP-3), and C-reactive protein (CRP), were examined annually. Linear mixed-effect models (LMM) were applied to investigate associations of time-varying BMI with trajectories of biomarkers. We additionally examined the modification effect of baseline BMI groups, menopausal status, and metabolic syndrome. RESULTS: BMI was associated with increased levels of RETN, CRP, sOB-R, and decreased levels of ADP at baseline. An increasing BMI rate was significantly associated with an average 3-year increase in RETN (ß = 0.019, 95% CI 0.004 to 0.034) and sOB-R (ß = 0.022, 95% CI 0.009 to 0.035), as well as a decrease in ADP (ß = - 0.006, 95% CI - 0.012 to 0.001). These associations persisted across different baseline BMI groups. An increasing BMI rate was significantly associated with an average 3-year increase in CRP levels among normal weight (ß = 0.045, 95% CI 0.001 to 0.088) and overweight (ß = 0.060, 95% CI 0.014 to 0.107) women. As BMI increased over time, a more remarkable decrease in ADP was observed among women with metabolic syndrome (ß = - 0.016, 95% CI - 0.029 to - 0.004) than those without metabolic syndrome at baseline. CONCLUSIONS: A higher increase rate of BMI was associated with poorer trajectories of inflammatory biomarkers related to BC risk. Recommendations for BMI reduction may benefit BC prevention in women, particularly for those with metabolic syndrome.

Temporal relationship between sleep duration and obesity among Chinese Han people and ethnic minorities.

BACKGROUND: No studies have assessed the association between sleep duration and obesity in Chinese ethnic minorities. Whether the relationship between sleep duration and obesity is different between Chinese Han people and Chinese ethnic minorities remains unclear. The study aimed to explore the relationship between sleep duration and obesity among Chinese Han people and Chinese ethnic minorities. METHODS: We applied data from the Guizhou Population Health Cohort Study (GPHCS), which 9,280 participants were recruited in the baseline survey from 2010 to 2012, and 8,163 completed the follow-up survey from 2016 to 2020. A total of 5,096 participants (3,188 Han Chinese and 1,908 ethnic minorities) were included in the ultimate analysis. Information on sleep duration (total 24-hour sleep time), body mass index (BMI), and waist circumference (WC) was collected at the baseline and follow-up survey, respectively. Cross-lagged panel analyses were conducted to explore the temporal relationship between sleep duration and obesity for Han people and ethnic minorities. RESULTS: For Han people, the results from cross-lagged panel analyses indicated that baseline sleep duration was significantly associated with follow-up BMI (ßBMI = -0.041, 95% CIBMI: -0.072 ~ -0.009) and follow-up WC (ßWC = -0.070, 95%CIWC: -0.103 ~ -0.038), but baseline BMI (ßBMI = -0.016, 95% CIBMI: -0.050 ~ 0.018) and baseline WC (ßWC = -0.019, 95% CIWC: -0.053 ~ 0.016) were not associated with follow-up sleep duration. In addition, the relationship between baseline sleep duration and follow-up BMI was gender-specific and significant only in the Han people female (ßBMI = -0.047, 95% CIBMI: -0.090 ~ -0.003) but not in the Han people male (ßBMI = -0.029, 95% CIBMI: -0.075 ~ 0.016). For ethnic minorities, the results indicated that there was no relationship between sleep duration and obesity at all, either from sleep duration to obesity (ßBMI = 0.028, 95%CIBMI: -0.012 ~ 0.068; ßWC = 0.020, 95%CIWC: -0.022 ~ 0.062), or from obesity to sleep duration (ßBMI = -0.022, 95%CIBMI: -0.067 ~ 0.022; ßWC = -0.042, 95%CIWC: -0.087 ~ 0.003). CONCLUSION: The relationship pattern between sleep duration and obesity across Han people and ethnic minorities is different. Future sleep-aimed overweight and obesity intervention should be conducted according to population characteristics.

Associations between changes of smartphone pedometer-assessed step counts and levels of obesity-related breast cancer biomarkers in non-cancer women: A population-based observational study.

While a higher level of physical activity (PA) is inversely associated with a higher breast cancer (BC) risk, the health benefits of daily steps on obesity-related BC biomarkers remain unclear. We aimed to understand the associations of changes in step counts with levels of five obesity-related BC biomarkers during a two-year follow-up. In total, 144 non-cancer women (47.96 ± 5.72) were observed on both 2019 and 2021. A structured questionnaire, daily steps and fasting blood samples were collected before (t0, 2019) and after (t1, 2021). Levels of biomarkers (IGF-binding proteins 3, adiponectin, soluble leptin receptor, C-reactive protein, and resistin) were assayed by ELISA. Participants were divided into persistent low steps, decreasing steps, increasing steps, and persistent high steps. Associations of categories on proposed biomarkers were estimated using linear regression models, with persistent low steps as reference. Associations between time-varying step counts with biomarkers were quantified using mixed linear models. Compared with persistent low steps, increasing steps is associated with a reduction in C-reactive protein level (ß=-0.74, 95%CI=-1.23--0.26, P-value = 2.98 × 10-3). An inverse association between time-varying step counts with C-reactive protein level was identified, consistent across different obesity types and baseline step level categories. No association with daily step counts was observed for other proteins.

Short-term ambient ozone exposure increases the risk of hospitalization with depression: a multi-city time-stratified case-crossover study.

BACKGROUND: Depression, the most common mental illness worldwide, has been studied and air pollution has been found to increase the risk of depression hospitalization, but research results on ozone (O3) remain limited. In this context, we investigated the relationship between short-term O3 exposure and depression-related hospital admissions (HAs). METHODS: The 10,459 records of HAs for depression from medical institutions across in 9 cities, China, were collected between 1 January 2017, and 31 December 2018. Air pollutants and meteorological data was obtained from provincial ecological environment monitoring stations in the study area. Conditional Poisson regression was employed to estimate the association between O3 and hospitalizations for depression, with data stratification by sex, age, weather, and economic level. RESULTS: Short-term O3 exposure was positively associated with the number of depression-related hospitalizations (Relative risk: 1.04 [95% CI: 1.02, 1.05]). O3 had a significant effect on the risk of depression-related hospitalizations on warm days (P = 0.021, Relative risk: 1.05 [1.03, 1.08]). The high gross domestic product group was more likely to be affected by O3 exposure-associated depression-related hospitalizations (P = 0.005, Relative risk: 1.03 [1.01, 1.05]). CONCLUSIONS: Short-term changes to O3 exposure may increase the risk of depression related hospitalizations, especially on warm days.

Prenatal and early postnatal exposure to ambient particulate matter and early childhood neurodevelopment: A birth cohort study.

Adverse impacts of prenatal or postnatal ambient particulate matter exposure have been identified on offspring neurodevelopment. However, it is unclear whether the effect in the two exposure periods is different for early childhood neurodevelopment. This study aimed to evaluate and compare the associations of prenatal and early postnatal exposure to ambient particulate matter with offspring neurodevelopment at 2 years of age and to identify which period was more sensitive to the effects of ambient particulate matter on offspring neurodevelopment. A total of 1331 mother-child pairs from a birth cohort were included in this study from October 2013 to September 2014 in Wuhan, China. The concentrations of ambient daily fine particulate matter (PM2.5) and particulate matter less than 10 µm in aerodynamic diameter (PM10) at each participant's home address during pregnancy and the first two years after birth were estimated by land-use regression models (LUR). Offspring neurodevelopment was measured by the Chinese revision of Bayley Scale of Infant Development (BSID-CR) for each child at 2 years of age. Mental developmental index (MDI) and psychomotor developmental index (PDI) from the BSID-CR were used as outcome variables. A generalized estimating equation (GEE) model was used to estimate the associations of prenatal and postnatal PM2.5 and PM10 exposure with offspring neurodevelopment. After adjusting for potential confounders, we found that both prenatal and early postnatal exposure to PM2.5 and PM10 were associated with decreased offspring MDI and PDI scores. Compared with prenatal exposure, the associations of early postnatal exposure to PM2.5 and PM10 with offspring MDI and PDI were stronger. This study indicates that exposure to ambient particulate matters, mainly during early postnatal period and to a lesser extent prenatally, is associated with impaired offspring neurodevelopment.

The short-term effects and burden of particle air pollution on hospitalization for coronary heart disease: a time-stratified case-crossover study in Sichuan, China.

BACKGROUND: Coronary heart disease (CHD), the leading cause of death globally, might be developed or exacerbated by air pollution, resulting high burden to patients. To date, limited studies have estimated the relations between short-term exposure to air pollution and CHD disease burden in China, with inconsistent results. Hence, we aimed to estimate the short-term impact and burden of ambient PM pollutants on hospitalizations of CHD and specific CHD. METHODS: PM10 and PM2.5 were measured at 82 monitoring stations in 9 cities in Sichuan Province, China during 2017-2018. Based on the time-stratified case-crossover design, the effects of short-term exposure to particle matter (PM) pollution on coronary heart disease (CHD) hospital admissions were estimated. Meanwhile, the linked burden of CHD owing to ambient PM pollution were estimated. RESULTS: A total of 104,779 CHD records were derived from 153 hospitals from these 9 cities. There were significant effects of PM pollution on hospital admissions (HAs) for CHD and specific CHD in Sichuan Province. A 10 µg/m3 increase of PM10 and PM2.5 was linked with a 0.46% (95% CI: 0.08, 0.84%), and 0.57% (95% CI: 0.05, 1.09%) increments in HAs for CHD at lag7, respectively. The health effects of air pollutants were comparable modified by age, season and gender, showing old (≥ 65 years) and in cold season being more vulnerable to the effects of ambient air pollution, while gender-specific effects is positive but not conclusive. Involving the WHO's air quality guidelines as the reference, 1784 and 2847 total cases of HAs for CHD could be attributable to PM10 and PM2.5, separately. The total medical cost that could be attributable to exceeding PM10 and PM2.5 were 42.04 and 67.25 million CNY from 2017 to 2018, respectively. CONCLUSIONS: This study suggested that the short-term exposure to air pollutants were associated with increased HAs for CHD in Sichuan Province, which could be implications for local environment improvement and policy reference.

Prenatal exposure to air pollutants and early childhood growth trajectories: A population-based prospective birth cohort study.

BACKGROUND: Air pollution exposure during pregnancy has been documented to be associated with impaired fetal growth and adverse birth outcomes, but the evidence regarding the effects of air pollution on early childhood growth is still limited. OBJECTIVE: We aimed to explore the associations of exposure to air pollutants during pregnancy with childhood growth trajectories from birth to age of 6 years. METHODS: A prospective cohort study based on the administrative registration system was conducted covering 62,540 births in Wuhan, China between January 1, 2011 and December 31, 2013 and followed for 6 years. Inverse distance weighted method was used to estimate the concentrations of air pollutants exposure for pregnant women. Group-based trajectory models (GBTM) were used to identify growth patterns of children: slow growth, normal growth, and rapid growth. Multinomial logistic regression models were used to examine the associations between prenatal exposure to air pollutants and childhood growth trajectories with adjustment for maternal age, educational status, pre-pregnancy BMI, residential areas, gestational diabetes, birth type, gender of infant, and breastfeeding duration. RESULTS: The mean (SD) of prenatal exposure concentrations for PM10, SO2, NO2, CO, and O3 were 107.9 (30.4), 32.8(12.6), 55.8(13.1), 1081.2(293.1), and 81.6(31.0) µg/m3 respectively. Compared with normal growth trajectory, increased PM10 and CO exposure were significantly associated with higher risk of slow growth trajectory but lower risk of rapid growth trajectory. An increase in prenatal exposure to NO2 significantly increased both the risk of slow growth trajectory and rapid growth trajectory. Increased prenatal SO2 exposure was significantly associated with rapid growth trajectory and was not associated with low growth trajectory. With O3 exposure levels increased, risk to be rapid growth trajectory decreased. Prenatal air pollutants exposure had a greater impact on childhood growth of children who were girls, and those mothers lived in rural areas and were normal weight before pregnancy. CONCLUSIONS: High levels of air pollutants exposure during pregnancy were associated with the risk of being in a trajectory with the deviation of BMI gain from birth to 6 years old. These findings suggest that efforts to identify children at risk of growth deviation in early childhood should pay attention to environmental exposure during pregnancy for their mothers.

Associations of exposure to fine particulate matter during pregnancy with maternal blood glucose levels and gestational diabetes mellitus: Potential effect modification by ABO blood group.

BACKGROUND: Previous studies have examined the relationships between prenatal fine particulate matter (PM2.5) exposure and gestational diabetes mellitus (GDM), but the results were inconsistent. Furthermore, the possible effect modification by ABO blood group has not been explored. OBJECTIVES: To assess the associations of PM2.5 exposures during pregnancy with maternal glucose levels as well as GDM, and further to evaluate the potential effect modification by ABO blood group. METHODS: Between January 2013 and January 2015, 4783 pregnant women were enrolled in our study based on a birth cohort in Wuhan. Daily PM2.5 exposure levels for each woman during pregnancy were estimated using a spatial-temporal land-use regression model. Linear regressions with general estimating equations (GEE) were performed to assess the associations between trimester-specific PM2.5 exposures and maternal glucose levels. Modified Poisson regressions with GEE analyses were used to evaluate the impacts of PM2.5 exposures during each trimester on the risk of GDM. The associations of PM2.5 exposure during the whole study period with glucose levels and GDM were estimated using multiple linear regression model and modified Poisson regression model, respectively. We conducted a stratified analysis to explore the potential effect modification by ABO blood group. RESULTS: Among all the 4783 participants, 394 (8.24%) had GDM. Exposure to PM2.5 was found to be positively associated with elevated fasting glucose level during the whole study period [0.382 mg/dL, 95% confidence interval (CI): 0.179-0.586, per 10 µg/m3 increase in PM2.5], the first trimester (0.154 mg/dL ,95% CI: 0.017-0.291) and the second trimester (0.541 mg/dL, 95% CI: 0.390-0.692). No statistically significant results were observed between PM2.5 and 1-h and 2-h glucose levels during any study period. Increased risks of GDM for each 10 µg/m3 increase in PM2.5 levels were observed during the whole study period [relative risk (RR): 1.120, 95% CI: 1.021-1.228] and the first trimester (RR: 1.074, 95% CI: 1.012-1.141), but not the second trimester (RR: 1.035, 95% CI: 0.969-1.106). Stratified analysis indicated that the associations of PM2.5 exposures with GDM were more pronounced among pregnant women with blood group A, but no significant effect modifications were observed. CONCLUSION: Our study enriched epidemiological evidence linking PM2.5 exposures during pregnancy to elevated maternal glucose levels and increased risk of GDM. More importantly, we first highlighted that the impact of PM2.5 on GDM might be greater among pregnant women with blood group A.

Repeated Measurements of Paraben Exposure during Pregnancy in Relation to Fetal and Early Childhood Growth.

Parabens are potential endocrine disruptors with short half-lives in the human body. To date, few epidemiological studies regarding repeated paraben measurements during pregnancy associated with fetal and childhood growth have been conducted. Within a Chinese prenatal cohort, 850 mother-infant pairs from whom a complete set of maternal urine samples were acquired during three trimesters were included, and the levels of five parabens were measured. We assessed the associations of both average and trimester-specific urinary paraben levels with weight and height z-scores at birth, 6 months, 1, and 2 years of age. In all infants, each doubling increase in average ethyl paraben (EtP) was associated with -2.82% (95% CI: -5.11%, -0.53%) decrease in weight z-score at birth, whereas no significant age-specific associations were identified. After stratifying by sex, we further observed age-specific association of average EtP with -3.96% (95% CI: -7.03%, -0.89%) and -3.38% (95% CI: 6.72%, -0.03%) reduction in weight z-scores at 1 and 2 years in males, respectively. Third-trimester EtP was negatively associated with weight z-scores at birth, 1 and 2 years in males. Our results suggested negative associations between prenatal paraben exposure and fetal and childhood growth, and the third trimester may be the window of susceptibility.

Association of air pollution with the risk of initial outpatient visits for tuberculosis in Wuhan, China.

OBJECTIVES: Previous studies suggested the association of air pollution with initial Mycobacterium tuberculosis infection and the disease development. However, few studies have been conducted on air pollution and initial tuberculosis (TB) consults using short-interval data. We investigated the weekly association between air pollution and initial TB outpatient visits. METHODS: We used a Poisson regression model combined with a distributed lag non-linear model to conduct a time-series study with weekly air pollution data and TB cases during 2014-2017 in Wuhan, China. RESULTS: A 10 µg/m3 increase in NO2 (nitrogen dioxide) was associated with 11.74% (95% CI: 0.70 to 23.98, lag 0-1 weeks), 21.45% (95% CI: 1.44 to 45.41, lag 0-2 weeks) and 12.8% (95% CI: 0.97 to 26.02, lag 0-1 weeks) increase in initial TB consults among all patients with TB, old patients (≥60 years old) and male ones, respectively. A 10 µg/m3 increase in SO2 (sulfur dioxide) was associated with -22.23% (95% CI: -39.23 to -0.49, lag 0-16 weeks), -28.65% (95% CI: -44.3 to -8.58, lag 0-16 weeks), -23.85 (95% CI: -41.79 to -0.37, lag 0-8 weeks) and -23.82% (95% CI: -41.31 to -1.11, lag 0-16 weeks) increase in initial TB consults among the total, young (aged 15-59 years old), old and male patients, respectively. In old patients, a 0.1 mg/m3 increase in CO (carbon monoxide) and a 10 µg/m3 increase in PM2.5 (particulate matter) were separately associated with 42.32% (95% CI: 1.16 to 100.22, lag 0-16 weeks) and 17.38% (95% CI: 0.28 to 37.38, lag 0-16 weeks) increases in TB consults. CONCLUSION: Our study first highlighted the importance of weekly association between air pollution and the risk of initial TB consults, which is helpful for the arrangements of TB screening and medical assistance.

Effect of residential exposure to green space on maternal blood glucose levels, impaired glucose tolerance, and gestational diabetes mellitus.

BACKGROUND: Residential surrounding green spaces can affect human health. However, limited studies have examined their impacts on maternal blood glucose homeostasis outcomes. OBJECTIVE: We examined the associations of residential exposure to green space with maternal blood glucose levels, gestational impaired glucose tolerance (IGT), and gestational diabetes mellitus (GDM). METHODS: Pregnant women were recruited from a prospective birth cohort between October 2012 and September 2015. Exposure to green space was calculated as the mean value of the normalized difference vegetation index (NDVI) within a 300-m circular buffer area surrounding each residence. Maternal glucose was measured between 24 and 28 weeks of gestation, and gestational IGT and GDM were diagnosed using valid methods. We estimated the associations of residential NDVI with maternal glucose levels using multiple linear regression models with adjustment for age, education, BMI, passive smoking during pregnancy, parity, season of conception, income, and urbancity. We estimated the relative risks of residential NDVI with IGT and GDM using a generalized estimating equation model with modified Poisson regression. The mediation effects of residential exposure to air pollution and maternal physical activity were assessed using causal mediation analysis. RESULTS: Of 6807 pregnant women, 751 (11.3%) and 604 (8.8%) were diagnosed with IGT and GDM, respectively. One SD increment of residential NDVI was associated with a decrease of 0.06 mmol/L (95% CI: -0.07, -0.05), 0.09 mmol/L (95% CI: -0.13, -0.05), and 0.06 mmol/L (95% CI: -0.09, -0.03) in maternal fasting glucose levels, 1-h glucose levels, and 2-h glucose levels, respectively, as well as reduced risks of incident IGT (RR: 0.92, 95% CI: 0.86, 0.99) and GDM (RR: 0.85, 95% CI: 0.79, 0.92). The association between residential NDVI and maternal fasting glucose levels was partly mediated by maternal exposure to PM2.5. CONCLUSION: Living with higher levels of green space was significantly associated with decreased maternal glucose levels and attenuated risks of incident maternal IGT and GDM. Our findings provide evidence linking green space to better maternal glucose outcomes. More studies are needed to further explore the maternal and child health benefits related to our findings.

Prenatal exposure to fine particulate matter, maternal hemoglobin concentration, and fetal growth during early pregnancy: associations and mediation effects analysis.

BACKGROUND: Fetal essential organ development is completed during early pregnancy which is important for fetal and postnatal health. However, the effect of exposure to PM2.5 on fetal growth during early pregnancy is less studied and the related mechanisms are largely unknown. METHODS: We conducted a birth cohort study of 1945 pregnant women with measurement of the fetal crown to rump length (CRL) by ultrasound between the gestational age of 11 and 14 weeks. We estimated residential exposures of PM2.5 from the date of LMP to the date of ultrasound examination using a spatial-temporal land use regression model. Maternal hemoglobin concentration was examined by maternal blood samples during the same gestational period or ±1 week of the ultrasound examination. The associations of exposure to PM2.5 with maternal hemoglobin concentration, and exposure to PM2.5 with fetal CRL during early pregnancy were estimated by multiple linear regression models. The mediation effect of maternal hemoglobin concentration on the association between exposure to PM2.5 and fetal CRL was explored by a casual mediation analysis. RESULTS: One IQR increment of prenatal exposure to PM2.5 was associated with a 0.929 g/L (95% CI: 0.068, 1.789) increase in maternal hemoglobin concentration, and associated with a -0.082 cm (95% CI: 0.139, -0.025) decrease in fetal CRL. One g/L increment of maternal hemoglobin concentration was associated a -0.011 cm (95% CI: 0.014, -0.008) decrease in fetal CRL. The mediation analysis indicated that 12.1% of the total effect of prenatal exposure to PM2.5 on reducing fetal CRL was mediated by increased maternal hemoglobin concentration. CONCLUSION: Exposure to PM2.5 was associated with reduced fetal growth during early pregnancy and elevated maternal hemoglobin concentration mediated this association.

Uptake of maternal care and childhood immunization among ethnic minority and Han populations in Sichuan province: a study based on the 2003, 2008 and 2013 health service surveys.

BACKGROUND: China has made remarkable progress in maternal and child health (MCH) over the last thirty years, but socio-economic inequalities persist. Ethnicity has become an important determinant of poor MCH outcomes, but little rigorous analytical work has been done in this area. To understand the socio-economic factors that explain ethnic variation in uptake of MCH care, we report the findings from an analysis in Sichuan province. METHODS: We linked data from the 2003, 2008 and 2013 National Health Service Surveys in Sichuan Province. The ethnic disparities in uptake of maternal care (completing 5 antenatal visits, giving birth in hospital and receiving a caesarean section) and childhood immunization (Bacillus Calmette Guerin (BCG), three doses of diphtheria (DPT) and measles immunization) were examined by geographical (Han district/county vs. ethnic minority county) and individual-based (Han women/children vs. ethnic minority women/children) comparisons. We also examined variation by distance to township and county hospitals, women's education, parity and age using weighted multilevel Poisson regressions with random intercept at district/county level. RESULTS: Ethnic inequalities in maternal care were marked, both at the geographical (district/county) and the individual level. The % of births in hospital was 90.7% among women in Han districts, compared to 83.3% among women living in Han counties (crude RR 0.93; 95% CI 0.75-1.15), 53.8% among Han women living in ethnic minority counties (crude RR 0.57; 95% CI 0.36-0.93), and 13.5% among ethnic minority women living in ethnic minority counties (crude RR 0.18; 95% CI 0.06-0.57). Adjusting the analysis for survey year, education, parity and distance to county level hospital weakened the association between geographical/individual ethnicity and uptake of maternity care, but associations remained remarkably strong. Coverage of childhood immunization was much higher than uptake of maternity care, and inequalities by ethnicity were much less pronounced. CONCLUSION: Lessons can be learned from China's successful immunization programme to further reduce inequalities in access to maternity care among ethnic minority populations in remote areas. Bringing the services closer to the women's homes and strengthening health promotion from the township to the village level may encourage more women to seek antenatal care and give birth in hospital.

Maternal exposure to fine particulate matter and the risk of fetal distress.

Prenatal life exposure to fine particulate matter (aerodynamic diameter less than or equal to 2.5 µm, PM2.5) has been linked with increased risk of adverse fetal development and birth outcomes in previous studies. However, to our knowledge, no study has investigated the association of maternal PM2.5 with the risk of fetal distress, which is a harmful fetal status and may lead to fetal brain damage, even fetal death. Therefore, we conducted a study to determine the association between maternal PM2.5 and fetal distress among 7835 mother-infant pairs from a birth cohort, in Wuhan, China, 2013-2015. The individual daily PM2.5 level was assessed using land use regression model. We evaluated the association of maternal PM2.5 level over the whole pregnancy with fetal distress by logistic regression model, and estimated the risk between PM2.5 exposure in specific trimester and fetal distress using generalized estimating equations. We observed that per 10 µg/m3 change of maternal PM2.5 level over the whole pregnancy was associated with 25% increased risk of fetal distress (95% confidence interval: 1.09-1.44). Further, we found PM2.5 level in the 2nd trimester, but not in the 1st and 3rd trimesters, was associated with fetal distress. Stratified analyses indicated that the association was only significant among infants who were born in cold seasons. Our study suggested that PM2.5 exposure during the whole pregnancy exhibited significant associations with the risk of fetal distress, and exposure in the 2nd trimester maybe the susceptible window. Further stratified analyses indicated that birth season is a possible modifier in the association.

Regional background ozone estimation for China through data fusion of observation and simulation.

Regional background ozone (O3_RBG) is an important component of surface ozone (O3). However, due to the uncertainties in commonly used Chemical Transport Models (CTMs) and statistical models, accurately assessing O3_RBG in China is challenging. In this study, we calculated the O3_RBG concentrations with the CTM - Brute Force Method (BFM) and constrained the results with site observations of O3 with the multiple linear regression (MLR) model. The annual average O3_RBG concentration in China region in 2020 is 35 ± 4 ppb, accounting for 81 ± 5 % of the maximum 8-h average O3 (MDA8 O3). We applied the random forest and Shapley additive explanations based on meteorological standardization techniques to separate the contributions of meteorology and natural emissions to O3_RBG. Natural emissions contribute more significantly to O3_RBG than meteorology in various Chineses regions (30-40 ppb), with higher contributions during the warm season. Meteorological factors show higher contributions in the spring and summer seasons (2-3 ppb) than the other seasons. Temperature and humidity are the primary contributors to O3_RBG in regions with severe O3 pollution in China, with their individual impacts ranging from 30 % to 62 % of the total impacts of all meteorological factors in different seasons. For policy implications, we tracked the contributions of O3_RBG and local photochemical reaction contributions (O3_LC) to total O3 concentration at different O3 levels. We found that O3_LC contribute over 45 % to MDA8 O3 on polluted days, supporting the current Chinese policy of reducing O3 peak concentrations by cutting down precursor emissions. However, as the contribution of O3_RBG is not considered in the policy, additional efforts are needed to achieve the control groal of O3 concentration. As the implementation of stringent O3 control measurements in China, the contribution of O3_RBG become increasingly significant, suggesting the need for attention to O3_RBG and regional joint prevention and control.