Is being childless associated with a woman's risk of overweight and obesity? Results from a national longitudinal study.

AIM: To examine the association between motherhood status (mothers, voluntarily childless, involuntarily childless) and overweight and obesity over 22 years. METHODS: A total of 4092 women aged 18-23 years were followed from 1996 to 2018. Motherhood status was defined by women's reports on their fertility, attempts to conceive, use of in vitro fertilisation and fertility hormones, and number of biological children. Associations between motherhood status and overweight and obesity were examined using generalised estimating equations models, adjusting for socio-demographic characteristics, lifestyle factors, depressive symptoms, early life factors, and polycystic ovary syndrome (PCOS). RESULTS: At age 40-45 years, 12% of women were voluntarily childless and 5% were involuntarily childless. The prevalence of overweight and obesity increased with age and women who were voluntarily or involuntarily childless had higher prevalence of obesity than mothers in all surveys. After adjusting for covariates, compared with mothers, women who were voluntarily childless had higher odds of being overweight (odds ratio [OR], 95% confidence interval [CI]: 1.29, 1.09-1.52) and obese (OR, 95% CI: 1.65, 1.29-2.12). Involuntary childlessness was not associated with being overweight (OR, 95% CI: 1.05, 0.82-1.33), and its association with obesity was attenuated after adjusting for PCOS in the final model (OR, 95% CI: 1.40, 0.99-1.98). CONCLUSIONS: Around one in nine Australian women remained voluntarily childless by their late reproductive years. On average, they had higher odds of being overweight and obese than mothers, suggesting that overweight and obesity prevention programs should consider tailoring their advice by motherhood status.

Do mothers or females without children have better health-related quality of life across their reproductive years?

PURPOSE: To compare health-related quality of life (HRQoL) between mothers and females who were voluntarily or involuntarily childless, across their reproductive years. METHODS: 4100 females born in 1973-78 from the Australian Longitudinal Study on Women's Health were followed for 22 years. Motherhood status was defined by females' reports in Survey 8 (2018, 40-45 years) on their fertility, attempts to conceive, use of in vitro fertilization and fertility hormones, and number of children. HRQoL was assessed in each survey using the 36-Item Short Form Survey (SF-36). Linear mixed models were used to assess the associations between motherhood status and HRQoL. RESULTS: Over 22 years, compared with females who were voluntarily childless, mothers on average had better HRQoL (shown by scores 1.5 to 3.4 points higher on five of the eight SF-36 subscales), while females who were involuntarily childless scored 2.2 to 3.0 points lower on three of eight SF-36 subscales. Compared with females who were voluntarily childless, teen mothers (age at first birth < 20 years) scored lower on role limitations due to physical problems subscale (b = -5.5, 95% CI: -9.3, -1.6), while females with either two, or three or more children scored 1.6 to 4.8 points higher on seven of eight SF-36 subscales. CONCLUSIONS: Females who were childless had poorer HRQoL than mothers. Further research is needed to understand the underlying mechanisms, which could inform policymakers on how to reduce the health disparities and improve long-term health outcomes for females.

The epidemiological evidence linking exposure to ambient particulate matter with neurodevelopmental disorders: A systematic review and meta-analysis.

BACKGROUND: There has been increasing attention on the associations between ambient particulate matter (PM) in early-life and neurodevelopmental disorders (NDDs). However, the associations remained unclear when considering different types of NDDs and different sizes of PM, and vulnerable exposure windows during early-life were not identified yet. OBJECTIVE: To synthesize the published literature on the associations between ambient particulate matter (PM) and risk of different types of neurodevelopmental disorders (NDDs) in a systematic review and meta-analysis. METHODS: A systematic search of Medline, Embase, PubMed, Cochrane Library, and Web of Science was performed from inception through 24 January 2022. Two reviewers conducted the study selection, data extraction, and quality appraisal. A random-effects model was used for meta-analyses with two quality-of-evidence assessments (the Grading of Recommendations Assessment, Development, and Evaluation system and the best evidence synthesis system). RESULTS: A total of 6554 articles were screened, of which 31 were included in the review, and 20 provided adequate data for meta-analyses. Exposures to particulate matter of 2.5 µm or less (PM2.5) during prenatal periods (OR, 1.32 [95%CI, 1.03-1.69]), the first year after birth (OR, 1.62 [95%CI, 1.22-2.15]) and the second year after birth (OR, 3.13 [95%CI, 1.47-6.67]) were associated with increased risk of autism spectrum disorders (ASD) in children. The quality of evidence for these associations during early postnatal periods was somewhat moderate with limited studies. We found inconsistent evidence when considering other types of NDDs and different sizes of PM. CONCLUSIONS AND RELEVANCE: Current evidence indicated that there might be an association between PM2.5 exposure and higher risk of ASD, and early postnatal periods appeared to be the critical exposure window. High-quality studies are needed to assess the evidence for other types of NDDs.

The relationship between online courses and mental health among Chinese children.

BACKGROUND: Previous studies on the association of online courses and mental health were mainly conducted in universities, and no study investigated the relationship between characteristics of online courses and children's mental health in primary and secondary school. This study aimed to explore the association of online courses and children's mental health in primary and secondary school. METHODS: A cross-sectional study was conducted through an online survey among 540 primary and secondary school students and their parents in the eastern, central and western region of China from April to May in 2020. Children's mental health was assessed by the Strengths and Difficulties Questionnaire (SDQ). Borderline mental health problems (SDQ total difficulties score ≥ 16) and mental health problems (SDQ total difficulties score ≥ 20) were defined according to Goodman's standard. Multivariable linear and logistic regression models were used to examine the association between online courses and children's mental health. RESULTS: Compared with those who did not have problems of online courses, children having the difficulty in understanding the content of online courses had a higher SDQ total difficulties score [ß = 1.80, 95% confidence interval (CI): 0.89, 2.71] and a higher risk of borderline mental health problems [odds ratio (OR) = 1.93, 95%CI: 1.07, 3.49], while device or internet connection problems were not significantly associated with children's mental health. Compared with children who had live courses, those having video-recorded courses had a higher SDQ total difficulties score (ß = 0.90, 95%CI: 0.01, 1.80). Children who spent more than 4 h on online courses had a higher SDQ total difficulties score than those of less than or equal to 4 h (ß = 0.95, 95%CI: 0.09, 1.81). CONCLUSION: We found that online courses with inappropriate characteristics were associated with children's mental health. The findings called for the efforts to optimize the online courses and improve children's mental health.

Prenatal exposure to airborne particulate matter of 1 µm or less and fetal growth: A birth cohort study in Beijing, China.

BACKGROUND: The association of airborne particulate matter of 1 µm or less (PM1) with fetal growth hasn't been studied. We aimed to investigate the association of PM1 with fetal growth parameters measured via ultrasonography and birth weight. METHODS: The birth cohort included 18,669 pregnant women who were pregnant between 2014 and 2017 in Tongzhou Maternal and Child Health Hospital of Beijing, China. The predicted PM1 concentration was matched with the residential addresses of each woman. The fetal abdominal circumference (AC), head circumference (HC), femur length (FL) and estimated fetal weight (EFW) were evaluated via ultrasonography, while birth weight was measured at birth. The fetal parameters and birth weight were standardized as gestational-age- and gender-adjusted Z-score. We defined undergrowth of fetal parameters, low birth weight (LBW) and small-for-gestational-age (SGA) as categorized outcomes. Generalized estimating equations and generalized linear regression were used to examine the associations of PM1 with quantitative and categorized outcomes, respectively. RESULTS: A 10 µg/m3 increase in PM1 was associated with decrement in the Z-scores of AC [-0.027, 95% confidence intervals (CI): -0.047~ -0.07]EFW (-0.055, 95%CI: -0.075~-0.035). These results remained robust after adjusting nitrogen dioxide and sulphur dioxide. We didn't observe significant results regarding the analyses of undergrowth of all fetal parameters and the analyses of birth weight outcomes. CONCLUSION: This study identified the negative associations between PM1 and fetal parameters in utero. The findings provided robust evidence that strategies for reducing PM1 exposure can prevent early-life health.

The individual and joint effects of maternal 25(OH)D deficiency and gestational diabetes on infant birth size.

BACKGROUND AND AIMS: To examine the independent effect of maternal serum 25-hydroxyvitamin D [25(OH)D] deficiency and its joint effect with gestational diabetes mellitus (GDM) on infant birth size. METHODS AND RESULTS: This retrospective cohort study was conducted in 15,724 mother-offspring dyads in Beijing, China between 2016 and 2017. Outcomes included infant birth weight Z-score (adjusted for gestational age and sex) and large for gestational age (LGA). Exposures were maternal 25(OH)D concentrations. Linear and logistic regression models were used to assess the associations of exposures with continuous and binary outcomes, respectively. Exposure-outcome associations were not observed when analyzing 25(OH)D concentrations continuously or in quartiles (P > 0.05); however, mothers with severely deficient 25(OH)D concentrations (n = 307) had a decreased risk of LGA compared with those with sufficient 25(OH)D concentrations (≥30.0 ng/mL; n = 5400) (adjusted odds ratio (OR): 0.63; 95% confidence interval (CI): 0.42, 0.93). Compared to mothers with no 25(OH)D deficiency (≥20.0 ng/mL) and no GDM (n = 7975), those with both 25(OH)D deficiency and GDM (n = 1090) had 0.15 (95% CI: 0.09, 0.21) higher infant birth weight Z-score and a higher risk of LGA (OR: 1.29; 95% CI: 1.09, 1.52). Maternal 25(OH)D deficiency and GDM had additive interaction on the risk of LGA (relative risk due to interaction: 0.18). CONCLUSION: Mothers with severely deficient 25(OH)D might have a decreased risk of LGA. However, the joint effect of maternal 25(OH)D deficiency and GDM might increase the risk of LGA. Our findings have clinical and public health implications and provide potential directions for future studies.

The sugar and energy in non-carbonated sugar-sweetened beverages: a cross-sectional study.

BACKGROUND: The consumption of non-carbonated sugar-sweetened beverages (NCSSBs) has many adverse health effects. However, the sugar and energy content in NCSSBs sold in China remain unknown. We aimed to investigate the sugar and energy content of NCSSBs in China and how these contents were labelled. METHODS: A cross-sectional survey was conducted in 15 supermarkets in Haidian District, Beijing from July to October 2017. The product packaging and nutrient information panels of NCSSBs were recorded to obtain type of products (local/imported), serving size, nutrient contents of carbohydrate, sugar and energy. For those NCSSBs without sugar content information, we used carbohydrate content as a replacement. RESULTS: A total of 463 NCSSBs met the inclusion criteria and were included in our analysis. The median of sugar content and energy content was 9.6 [interquartile range (IQR): 7.1-11.3] g/100 ml and 176 (IQR: 121-201) kJ/100 ml. The median of sugar contents in juice drinks, tea-based beverages, sports drinks and energy drinks were 10.4, 8.5, 5.0 and 7.4 g/100 ml. Imported products had higher sugar and energy content than local products. There were 95.2% products of NCSSBs receiving a 'red'(high) label for sugars per portion according to the UK criteria, and 81.6% products exceeding the daily free sugar intake recommendation from the World Health Organization (25 g). There were 82 (17.7%) products with sugar content on the nutrition labels and 60.2% of them were imported products. CONCLUSIONS: NCSSBs had high sugar and energy content, and few of them provided sugar content information on their nutrition labels especially in local products. Measures including developing better regulation of labelling, reducing sugar content and restricting the serving size are needed for reducing sugar intakes in China.

Associations between factors in childhood and young adulthood and childlessness among women in their 40s: A national prospective cohort study.

BACKGROUND: While the risk factors for infertility are well-established, research on factors associated with voluntary childlessness is limited and mainly focused on adulthood factors. Thus, we examined the associations between factors in childhood and young adulthood and different types of childlessness. METHODS: The analysis included 4653 women from the Australian Longitudinal Study on Women's Health from 1996 to 2021. Childlessness was categorised as: voluntary, due to infertility issues, or due to other reasons. The associations between factors in childhood and young adulthood and childlessness were assessed using multinomial logistic regression models. RESULTS: In their 40s, 4.8 % of women were voluntarily childless, 6.7 % were childless due to infertility issues, and 7.8 % were childless due to other reasons. Regardless of types of childlessness, being childless was associated with poorer self-rated health during childhood and having been unpartnered and obese in young adulthood. Ex-smokers in young adulthood had lower odds of childlessness. Childhood physical abuse was associated with childlessness due to infertility issues and other reasons. Voluntary childlessness and childlessness due to infertility issues were associated with having identified as non-exclusively heterosexual in early adulthood. Lower social support in early adulthood was associated with voluntary childlessness and childlessness due to other reasons. LIMITATIONS: The direction of the associations could not be determined and using self-reported data may introduce recall bias. CONCLUSIONS: Factors in childhood and young adulthood were associated with different types of childlessness, highlighting the importance of adopting a life course perspective when studying childlessness.

Childhood socioeconomic disadvantage and risk of physical multimorbidity in later life: The mediating role of depression.

OBJECTIVE: To assess the impact of childhood socioeconomic disadvantage (SED) on the risks of depression and physical multimorbidity in later life and to explore whether depression mediates the association between childhood SED and physical multimorbidity. METHODS: Data on 8214 adults from the China Health and Retirement Longitudinal Study were analyzed. The mean (SD) age of the study population was 57.0 (8.0) years at baseline (2011) and 51.9 % were females. Multivariable logistic regressions were used to examine the associations of childhood SED (indexed by food insecurity, highest education level of parents, and self-perceived household financial situation, and scored 0-3) with later-life depression (scored ≥10 on the 10-item Center for Epidemiologic Studies Depression Scale) and physical multimorbidity (having two or more doctor-diagnosed chronic conditions) assessed in the 2018 follow-up survey. Mediation analysis was conducted in the overall sample and further stratified by sex to estimate the degree to which the association between childhood SED and physical multimorbidity could be explained by baseline depression. RESULTS: Participants with a childhood SED score of 3 (i.e., the most disadvantaged) had 2.63 (95 % confidence interval [CI]: 1.91-3.63) times and 2.08 (95 % CI: 1.56-2.77) times higher odds of depression and physical multimorbidity respectively compared with those who had a score of 0 (i.e., the least disadvantaged). Depression mediated 20 % of the association between childhood SED and physical multimorbidity (36 % in females and 5 % in males). CONCLUSIONS: Childhood SED was associated with higher risks of depression and physical multimorbidity in later life, and the association of childhood SED with physical multimorbidity was mediated by depression, especially among females.

Risk of Gestational Diabetes Mellitus in relation to Plasma Concentrations of Fatty Acid-Binding Protein 4: A Nested Case-Control Study in China.

OBJECTIVE: The study is aimed at examining the effects of fatty acid-binding protein 4 (FABP4) on insulin resistance and gestational diabetes mellitus (GDM). METHODS: Based on a prospective birth cohort in Beijing, China, we conducted a nested case-control study and analyzed 135 GDM case-control pairs matched by age and the gestational week when they took the oral glucose tolerance test. We performed linear regression to analyze the association of plasma FABP4 concentrations with insulin resistance. We used logistic regression to estimate odds ratios (ORs) of FABP4 for GDM, controlling for potential confounders, including dietary intake and physical activity. RESULTS: Plasma FABP4 levels in the first and second trimesters were positively associated with fasting insulin and homeostasis model assessment for insulin resistance (HOMA-IR) in the second trimester (both P < 0.001). Compared with those in the lowest FABP4 tertile, women in the highest tertile of FABP4 levels in the first and second trimesters had 1.053 times (OR = 2.053, 95% CI 1.091 to 3.863) and 1.447 times (OR = 2.447, 95% CI 1.305 to 4.588) higher risk of developing GDM. CONCLUSIONS: Elevated FABP4 levels in the first and second trimesters were associated with a higher level of insulin resistance and greater GDM risk, indicating FABP4 might predict women with high risk of developing GDM.

Early Pregnancy Exposure to Rare Earth Elements and Risk of Gestational Diabetes Mellitus: A Nested Case-Control Study.

Objective: The extensive use of rare earth elements (REEs) in many technologies was found to have effects on human health, but the association between early pregnancy exposure to REEs and gestational diabetes mellitus (GDM) is still unknown. Methods: This nested case-control study involved 200 pregnant women with GDM and 200 healthy pregnant women from the Peking University Birth Cohort in Tongzhou. We examined the serum concentrations of 14 REEs during early pregnancy and analyzed their associations with the risk of GDM. Results: When the elements were considered individually in the logistic regression model, no significant associations were found between REEs and GDM, after adjusting for confounding variables (P > 0.05). In weighted quantile sum (WQS) regression, each quartile decrease in the mixture index for REEs resulted in a 1.67-fold (95% CI: 1.12-2.49) increased risk of GDM. Neodymium (Nd), Praseodymium (Pr), and Lanthanum (La) were the most important contributors in the mixture. Conclusion: The study findings indicated that early pregnancy exposure to lower levels of REE mixture was associated with an increased risk of GDM, and Nd, Pr, and La exhibited the strongest effects in the mixture.

Combined Effect of Maternal Vitamin D Deficiency and Gestational Diabetes Mellitus on Trajectories of Ultrasound-Measured Fetal Growth: A Birth Cohort Study in Beijing, China.

OBJECTIVE: Few studies have examined whether maternal 25(OH)D deficiency and gestational diabetes mellitus (GDM) jointly affect fetal growth. We aimed to examine the separate and combined effects of maternal 25(OH)D deficiency and GDM on trajectories of fetal growth. METHODS: We established a birth cohort (2016-2017) with 10,913 singleton pregnancies in Tongzhou Maternal and Child Health Hospital of Beijing, China. Maternal 25(OH)D deficiency (serum 25(OH)D concentration < 20.0 ng/mL) was detected, and GDM was diagnosed at 24~28 gestational weeks. Fetal growth was assessed by longitudinal ultrasound measurements of estimated fetal weight (EFW) and abdominal circumference (AC) from 28 gestational weeks to delivery, both of which were standardized as gestational-age-adjusted Z-score. A k-means algorithm was used to cluster the longitudinal measurements (trajectories) of fetal growth. Logistic regression models were used for estimating exposure-outcome associations and additive interactions. RESULTS: We identified two distinct trajectories of fetal growth, and the faster one resembling the 90th centile curve in the reference population was classified as excessive fetal growth. Maternal 25(OH)D deficiency and GDM were independently associated with an increased risk of excessive fetal growth. The combination of maternal 25(OH)D deficiency and GDM was associated with an increased risk of excessive fetal growth assessed by EFW Z-score (odds ratio (OR): 1.36; 95% confidence interval (CI): 1.15~1.62) and AC Z-score (OR (95% CI): 1.32 (1.11~1.56)), but the relative excess risks attributable to interaction were nonsignificant (P > 0.05). CONCLUSION: Maternal 25(OH)D deficiency and GDM may jointly increase the risk of excessive fetal growth. Interventions for pregnancies with GDM may be more beneficial for those with 25(OH)D deficiency than those without regarding risk of excessive fetal growth, if confirmed in a large sample.

Plasma retinol-binding protein 4 in the first and second trimester and risk of gestational diabetes mellitus in Chinese women: a nested case-control study.

BACKGROUND: To assess the association between plasma retinol-binding protein 4 (RBP4) levels both in the first trimester and second trimester and risk of gestational diabetes mellitus (GDM). METHODS: Plasma RBP4 levels and insulin were measured among 135 GDM cases and 135 controls nested within the Peking University Birth Cohort in Tongzhou. Multivariable linear regression analysis was conducted to assess the influence of RBP4 levels on insulin resistance. Conditional logistic regression models were used to compute the odds ratio (OR) and 95% confidence interval (CI) between RBP4 levels and risk of GDM. RESULTS: The GDM cases had significantly higher levels of RBP4 in the first trimester than controls (medians: 18.0 µg/L vs 14.4 µg/L; P < 0.05). Plasma RBP4 concentrations in the first and second trimester were associated with fasting insulin, homeostasis model assessment for insulin resistance (HOMA-IR), and the quantitative insulin sensitivity check index (QUICKI) in the second trimester (all P < 0.001). With adjustment for diet, physical activity, and other risk factors for GDM, the risk of GDM increased with every 1-log µg/L increment of RBP4 levels, and the OR (95% CI) was 3.12 (1.08-9.04) for RBP4 in the first trimester and 3.38 (1.03-11.08) for RBP4 in the second trimester. CONCLUSIONS: Plasma RBP4 levels both in the first trimester and second trimester were dose-dependently associated with increased risk of GDM.

Effects of dynamic change in fetuin-A levels from the first to the second trimester on insulin resistance and gestational diabetes mellitus: a nested case-control study.

OBJECTIVE: To examine the effects of dynamic change in fetuin-A levels before the diagnosis of gestational diabetes mellitus (GDM) on insulin resistance and GDM. RESEARCH DESIGN AND METHODS: A total of 135 women with GDM and 135 normal glucose tolerance (NGT) women with matched age (±2 years old) and gestational age at taking the oral glucose tolerance test (OGTT) were included in this nested case-control study. Fasting venous blood samples were collected at the prenatal visit of the first trimester and during OGTT of the second trimester. Plasma concentration of fetuin-A and insulin was determined. RESULTS: The plasma fetuin-A concentration in women with GDM was significantly higher than NGT controls in both the first trimester (medians: 403.0 pg/mL vs 273.4 pg/mL; p<0.05) and the second trimester (medians: 475.7 pg/mL vs 290.8 pg/mL; p<0.05) and notably increased from the first to the second trimester. Multivariate linear regression analysis showed that the change in fetuin-A concentration was associated with the changes in fasting insulin, homeostasis model assessment (HOMA) of insulin resistance, and HOMA of ß-cell function (HOMA-ß) (p<0.05). The highest quartile of the increase in fetuin-A concentration from the first to the second trimester was associated with a higher risk of developing GDM compared with the lowest quartile (OR 2.14; 95% CI 1.05 to 4.37). CONCLUSIONS: The dynamic change in fetuin-A levels was associated with the changes in insulin resistance and ß-cell function from the first to the second trimester, and was associated with an increased risk of the development of GDM, indicating that fetuin-A could be a biomarker to predict the risk of GDM. TRIAL REGISTRATION NUMBER: NCT03814395.

The associations of particulate matters with fetal growth in utero and birth weight: A birth cohort study in Beijing, China.

BACKGROUND: Previous studies examined the associations of particulate matters (PM) with fetal growth in utero or birth weight with inconsistent results, and few studies investigated that whether the associations of PM with fetal growth in utero also present at birth. We aimed to investigate the associations of PM with both fetal growth in utero and birth weight. METHODS: We established a birth cohort (2014-2017) with 18,863 singleton pregnancies in Tongzhou Maternal and Child Hospital of Beijing, China. Maternal exposure to PM with aerodynamic diameters ≤2.5 µm and ≤ 10 µm (PM2.5/PM10) during pregnancy was estimated using the inverse distance weighting method. Estimated birth weight (EFW) was assessed by ultrasound measurements and birth weight was measured at birth, which were both standardized as gestational-age- and gender-adjusted Z-score. EFW undergrowth, low birth weight (LBW) and small-for-gestational-age were defined as the categorized outcomes. Generalized estimating equations and generalized linear regression were used to examine the associations of PM with quantitative and categorized outcomes, controlling for temperature, greenspace and individual covariates. RESULTS: A 10 µg/m3 increase in PM2.5 and PM10 were associated with lower EFW Z-score [-0.031, 95% confident interval (CI): -0.047, -0.016 and -0.030, 95% CI: -0.043, -0.017]. A 10 µg/m3 increase in PM2.5 was associated with lower birth weight Z-score (-0.035, 95% CI: -0.061, -0.010) and higher risk of LBW (OR = 1.240, 95% CI: 1.019, 1.508). These results remained robust in co-pollutant models and sensitivity analyses. We didn't find significant results in other analyses. CONCLUSIONS: The study identified an inverse association between PM and fetal growth in utero. The association between PM2.5 and fetal growth persisted from pregnancy to birth. This study supported that further actions towards controlling air pollution are strongly recommended for promoting early-life health.

Maternal severe stressful life events and risk of abnormal vaginal bleeding among urban Chinese pregnant women.

Objective: The objective of this study is to assess whether maternal stressful life events are associated with increased risk of vaginal bleeding in urban China.Methods: We implemented a cross-sectional study to examine the association between maternal severe stressful life events and vaginal bleeding in early pregnancy. Information was collected from an urban area and 956 participants were involved in final analysis. Multivariable logistic model was used to estimate the adjusted odds ratio (OR) and 95% confidence interval (95% CI) controlling for confounders.Results: In total, 219 of the 956 participants were reported vaginal bleeding. Maternal stressful life events would increase the chance of vaginal bleeding with a crude OR of 2.14 (95% CI, 1.53-2.99). After adjustment for potential variables, the association remains significant (adjusted OR, 2.22; 95% CI, 1.56-3.16), and stratification analysis shows parity is an influence factor. The frequency of maternal stress and vaginal bleeding exist a dose-response relationship.Conclusion: Maternal stressful life events are associated with the risk of vaginal bleeding in urban China. The parity status influences their association.

The associations of residential greenness with fetal growth in utero and birth weight: A birth cohort study in Beijing, China.

BACKGROUND: Although studies have examined the association between residential greenness and birth weight, there is no evidence regarding the association between residential greenness and fetal growth in utero. We aimed to investigate the associations of residential greenness with both fetal growth in utero and birth weight. METHODS: A birth cohort (2014-2017) with 18,665 singleton pregnancies was established in Tongzhou Maternal and Child hospital of Beijing, China. Residential greenness was matched with maternal residential address and estimated from remote satellite data using normalized difference vegetation index with 200 m and 500 m buffers (NDVI-200 and NDVI-500). Fetal parameters including estimated fetal weight (EFW), abdominal circumference (AC), head circumference (HC) and femur length (FL) were assessed by ultrasound measurements during pregnancy. Fetal parameters were standardized as gestational-age- and gender-adjusted Z-score and undergrowth was defined as Z-score < -1.88. Birth weight Z-score, low birth weight (LBW) and small for gestational age (SGA) were assessed as birth outcomes. Generalized estimating equations with the autoregressive working correlation structure and generalized linear regression were used to examine the associations of residential greenness with quantitative and categorized outcomes. RESULTS: We found an increase Z-score of EFW [0.054, 95% confidence interval (CI): 0.020-0.087], AC (0.045, 95%CI: 0.011-0.080) and HC (0.054, 95%CI: 0.020-0.089) associated with residential greenness above NDVI-500 median compared to less than and equal to NDVI-500 median. Stratified analyses indicated that the associations might be stronger in women exposed to lower levels of particles with aerodynamic diameters ≤2.5 µm. No associations were found in the analyses of NDVI-250 with fetal growth in utero. We didn't observe significant associations of NDVI with birth weight Z-score, LBW and SGA. CONCLUSIONS: This study identified a positive association of NDVI-500 and fetal growth in utero, but we didn't observe its association with birth weight measures. Our results suggest that building sufficient green infrastructure might potentially promote early life health.

Excessive gestational weight gain and the risk of gestational diabetes: Comparison of Intergrowth-21st standards, IOM recommendations and a local reference.

AIMS: To compare the abilities of Intergrowth-21st standards, Institute of Medicine (IOM) recommendations and a Chinese reference on gestational weight gain (GWG) to identify women at risk of gestational diabetes (GDM) and GDM-related adverse outcomes. METHODS: A retrospective cohort study was conducted on 13,366 women delivering live singleton infants between 2013 and 2017 in Tongzhou district of Beijing, China. Poisson regression with robust error estimates was used to estimate risk ratios (RRs) of GDM in different GWG groups according to three standards. RESULTS: There were 39.97%, 46.31% and 30.03% of women gaining weight above Intergrowth-21st standards, IOM recommendations and the Chinese reference respectively. Women with GWG above Intergrowth-21st standards and the Chinese reference had 27% (aRR, 1.27 95% CI, 1.18-1.37) and 30% (aRR, 1.30; 95% CI, 1.21-1.40) increased risks of GDM respectively, as compared to 22% (aRR, 1.22; 95% CI, 1.13-1.32) for IOM recommendations. GWG above either of these three standards was associated with macrosomia and cesarean delivery (P < 0.05). CONCLUSION: Compared with IOM recommendations, GWG above Intergrowth-21st standards or the Chinese reference was associated with higher risks of GDM and GDM-related adverse outcomes. Furthermore, these two prospective standards could additionally assess the severity of abnormal GWG and are feasible for dynamic monitoring.

Sugar and energy content of carbonated sugar-sweetened beverages in Haidian District, Beijing: a cross-sectional study.

OBJECTIVE: The consumption of carbonated sugar-sweetened beverages (CSSBs) is associated with a range of health problems, but little is known about the sugar and energy content of CSSBs in China. The study aimed to investigate the sugar and energy content of CSSBs in Beijing, China. STUDY DESIGN: We carried out a cross-sectional survey in 15 different supermarkets from July to October 2017 in Haidian District, Beijing. METHODS: The product packaging and nutrient labels of CSSBs were recorded by a snapshot in time to obtain company name, product name, serving size, and nutrient content, that is, carbohydrate, sugar and energy. For CSSB labels not showing sugar content, we used carbohydrate content as substitute. The sugar and energy content of CSSBs within each type of flavour were compared using Kruskal-Wallis test. The sugar content within the recommended levels was described using frequency. We also compared the sugar and energy content of top 5 CSSBs in terms of sales among three countries (China, UK and USA). RESULTS: A total of 93 CSSB products were found. The median sugar content was 9.3 (IQR: 5.7-11.2) g/100 mL, and the energy content was 38 (IQR: 23-46) kcal/100 mL. There were 79 products labelled 'Red' (high) per serving based on the criteria set in the UK (>11.25 g/100 mL). We found 62.4% of CSSBs had sugar content per serving that exceeds the daily free sugar intake for adults (25 g) recommended by the WHO. Some of the branded products sold in China had higher sugar content when they were compared with those in Western countries. CONCLUSIONS: CSSBs in Beijing, China have high sugar and energy content. Reduction in sugar content and serving size of CSSBs and taxation policy on beverages will be beneficial in reducing sugar intake in China.