Ying Yang

Status of HBsAg seroprevalence in 15 million rural couples in China: a cross-sectional study

A cross-sectional analysis of prevalence of hepatitis B virus infection (HBV) among rural couples was conducted between 2010 and 2014. Serologic HBV markers, including hepatitis B surface antigen (HBsAg) and e antigen (HBeAg), were tested. Primary outcome of interest comprised HBsAg positivity in couples (both positive: F+M+, only wife positive: F+M−, only husband positive: F−M+), and secondary outcome consisted of prevalence and risk factors of HBsAg positivity among husbands or wives. Of 14,816,300 couples included, 0.7% were F+M+; 6.3% were F−M+; 4.4% were F+M−, resulting in the overall seroprevalence of 11.4%. Individually, 6.1% were HBsAg positive with a higher rate seen in husbands (7.0%) than in wives (5.2%). Wife’s HBeAg(+)/HBsAg (+) (AORu2009=u20092.61), HBeAg(−)/HBsAg (+) (AORu2009=u20092.23), positivity of syphilis (AORu2009=u20091.50), living in a high-risk region (AORu2009=u20091.46) were significantly predictors of HBsAg positivity in husbands. Prevalence and predictors of HBsAg positivity in wives had similar results. Our data show a high burden and discordant pattern of HBV infection in rural couples, and partner’s double positivity of HBeAg and HBsAg was the most significant factor of HBV infection in couples. A comprehensive strategy that emphasizes vaccination and education is needed.

Association of Long-term Exposure to Airborne Particulate Matter of 1 μm or Less With Preterm Birth in China

Importance Airborne particulate matter pollution has been associated with preterm birth (PTB) in some studies. However, most of these studies assessed only populations living near monitoring stations, and the association of airborne particulate matter having a median diameter of 1 &mgr;m or less (PM1) with PTB has not been studied. Objective To evaluate whether PM1 concentrations are associated with the risk of PTB. Design, Setting, and Participants This national cohort study used National Free Preconception Health Examination Project data collected in 324 of 344 prefecture-level cities from 30 provinces of mainland China. In total, 1 300 342 healthy singleton pregnancies were included from women who were in labor from December 1, 2013, through November 30, 2014. Data analysis was conducted between December 1, 2016, and April 1, 2017. Exposures Predicted weekly PM1 concentration data collected using satellite remote sensing, meteorologic, and land use information matched with the home addresses of pregnant women. Main Outcomes and Measures Preterm birth (<37 gestational weeks). Gestational age was assessed using the time since the first day of the last menstrual period. Cox proportional hazards regression analysis was used to examine the associations between trimester-specific PM1 concentrations and PTB after controlling for temperature, seasonality, spatial variation, and individual covariates. Results Of the 1 300 342 singleton live births at the gestational age of 20 to 45 weeks included in this study, 104 585 (8.0%) were preterm. In fully adjusted models, a PM1 concentration increase of 10 &mgr;g/m3 over the entire pregnancy was significantly associated with increased risk of PTB (hazard ratio [HR], 1.09; 95% CI, 1.09-1.10), very PTB as defined as gestational age from 28 through 31 weeks (HR, 1.20; 95% CI, 1.18-1.23), and extremely PTB as defined as 20 through 27 weeks’ gestation (HR, 1.29; 95% CI, 1.25-1.34). Pregnant women who were older (30-50 years) at conception (HR, 1.13; 95% CI, 1.11-1.14), were overweight before pregnancy (HR, 1.13; 95% CI, 1.11-1.15), had a rural household registration (HR, 1.09; 95% CI, 1.09-1.10), worked as farmers (HR, 1.10; 95% CI, 1.09-1.11), and conceived in autumn (HR, 1.48; 95% CI, 1.46-1.50) appeared to be more sensitive to PM1 exposure than their counterparts. Conclusions and Relevance Results from this national cohort study examining more than 1.3 million births indicated that exposure to PM1 air pollution was associated with an increased risk of PTB in China. These findings will provide evidence to inform future research studies, public health interventions, and environmental policies.

The association between ambient temperature and the risk of preterm birth in China

BACKGROUNDnWith the gradual increase of global warming, the impact of extreme temperatures on health has become a focus of attention, however, its relationship with preterm birth remains unclear.nnnOBJECTIVESnTo investigate the association between exposure to extreme temperatures and preterm birth.nnnMETHODSnTemperature exposures and birth outcomes of 1,020,471 pregnant women from 132 cities in China were investigated. The pregnancy process was divided into different pregnancy periods. Study areas were divided into three categories (cold, medium, and hot areas) according to the local average temperature by cluster analysis. Average temperature data for each province used in the cluster analysis came from the China Statistical Yearbook 2013. Logistic regression was used to compare the effects of exposure to hot and cold conditions on the outcomes of pregnancy in different periods and regions.nnnRESULTSnA total of 1,020,471 singleton births were included, of which 73,240(7.2%) were preterm births. Compared with moderate temperatures (5th to 95th percentile), heat exposure (>95th percentile) in different periods of pregnancy increased the risk of preterm birth in hot areas. The most obvious increase was during the 3 months before pregnancy (odds ratio (OR)=1.229, 95% confidence interval (CI): 1.166-1.295). In contrast to heat exposure, cold exposure (<5th percentile) in hot areas reduced the risk of preterm birth; the protective effect was most pronounced in the 3 months before pregnancy (OR=0.784, 95% CI: 0.734-0.832). In medium and cold areas cold exposure also reduced the risk of preterm birth. The effect of exposure to extreme ambient temperatures throughout the entire pregnancy on preterm birth was similar to those of the periods above.nnnCONCLUSIONSnAcute and chronic exposure to extreme temperatures may affect the risk of preterm birth. Extreme heat is a risk factor for preterm birth and extreme cold is a protective factor.

Long‐Term Effects of Ambient Particulate Matter (With an Aerodynamic Diameter ≤2.5 μm) on Hypertension and Blood Pressure and Attributable Risk Among Reproductive‐Age Adults in China

Background Epidemiological evidence on the association between long‐term exposure to ambient fine particulate matter (with an aerodynamic diameter ≤2.5 μm; PM 2.5) and hypertension is mixed. We investigated the long‐term association between ambient fine particles and hypertension in reproductive‐age adults. Methods and Results This analysis included 39 348 119 reproductive‐age (20–49 years) participants from the National Free Preconception Health Examination Project from April 22, 2010 to December 31, 2015 across China. The estimation of annual average ambient PM 2.5 concentrations for each community was realized through using satellite‐based spatial statistical models. Linear mixed models and 2‐level logistic regressions adjusted for potential confounders with natural cubic splines were used to investigate the shape of PM 2.5–blood pressure and PM 2.5‐hypertension, respectively. The effect modification by sex, obesity, smoking status, age, diabetes mellitus, urbanity, race, and region was also taken into account. The concentration‐response relationship between PM 2.5 and hypertension was nonlinear, with a threshold concentration of 47.9 μg/m3. The odds ratio of hypertension related to a 10‐μg/m3 increase in PM 2.5 above threshold was 1.010 (95% confidence interval, 1.007–1.012). A 10‐μg/m3 increase in PM 2.5 above threshold corresponded to a 0.569 (95% confidence interval, 0.564–0.573) mm Hg elevation in systolic blood pressure and a 0.384 (95% confidence interval, 0.381–0.388) mm Hg elevation in diastolic blood pressure. There were 2.3% (95% confidence interval, 2.2%–2.4%) of the hypertension cases that could be attributed to PM 2.5 exposures in reproductive‐age adult populations. Conclusions Long‐term exposures to PM 2.5 above certain levels might increase population risk for hypertension and might be responsible for Chinas avoidable hypertension burden in reproductive‐age adults.

Prevalence of chronic hepatitis B and status of HBV care among rural women who planned to conceive in China

Globally, one third of prevalent chronic hepatitis B (CHB) virus infection (HBV) occurred in China. Assessing the prevalence of CHB infesction and status of HBV-related services among pre-conception women will provide insight into risks of mother to child transmission (MTCT). A cross-sectional analysis of data from the National Free Pre-pregnancy Checkups (NFPC) program in 2010–2014 was conducted. A standardized questionnaire which collected demographic information and enzyme-linked immunosorbent assays (ELISA) which tested serological HBV markers were applied. A total of 16,051,850 rural women aged 15–49 years were included. 5.2% of women were infected with CHB, among whom, 28.6% were also hepatitis B e antigen (HBeAg) positive. The most CHB concentrated places were distributed in southeastern coastal provinces. Women born after 1992 did not experience a higher level of vaccine-induced immunity compared to those born before 1992. Nine in ten rural women with CHB were not aware of their HBV status and a very small proportion of women (0.22%) had received antiviral treatment. Our data demonstrated an overall high-intermediate burden of CHB. Heterogeneity of geographic distribution, high proportion of HBeAg, insufficient awareness of HBV status, and low access to HBV treatment are challenges for preventing the MTCT.

Association of Husband Smoking With Wife's Hypertension Status in Over 5 Million Chinese Females Aged 20 to 49 Years

Background The effect of second‐hand smoking, especially husband smoking, on wifes hypertension has not been well studied. The current study was aimed to assess the association of husband smoking with wifes hypertension among females aged 20 to 49 years. Methods and Results This study included 5 027 731 females along with their husbands from the National Free Pre‐pregnancy Checkup Projects conducted across 31 provinces in China in 2014. Smoking/passive smoking status was collected by a standard questionnaire and blood pressure was measured by an electronic device after 10 minutes rest. Odds ratios and their corresponding 95% CIs for female hypertension were estimated according to smoking status of husband and wife, husbands smoking amount, and cumulative exposure to husband smoking. Compared with neither‐smoker group, the multivariable‐adjusted odds ratio for female hypertension was 1.28 (1.27–1.30), 1.53 (1.30–1.79), and 1.50 (1.36–1.67) in husband‐only, wife‐only, and mixed group, respectively. Furthermore, a higher risk of having hypertension was associated with amount and cumulative exposure of husband smoking. For example, compared with neither‐smoker, the multivariate‐adjusted odds ratio was 1.22 (1.19–1.25), 1.24 (1.21–1.26), 1.32 (1.26–1.37), 1.37 (1.34–1.41), and 1.75 (1.64–1.87) for females whose husband smoked 1 to 5, 6 to 10, 11 to 15, 16 to 20, and ≥21 cigarettes per day, respectively (P for trend<0.001). Subgroup analyses identified similar results. Conclusions There were associations of husband smoking with female hypertension prevalence. A family‐based smoking restriction strategy may reduce smoking in males and improve hypertension control in females.

The association between ambient PM2.5 exposure and the risk of preterm birth in China: A retrospective cohort study

BACKGROUNDnThe relationship between PM2.5 exposure and preterm birth remains unclear.nnnOBJECTIVESnTo explore the effect of exposure to PM2.5 on preterm birth in China.nnnMETHODSnThe birth outcomes of 426,246 pregnant women enrolled between January 2014 and December 2014 in NFPCP (National Free Pre-pregnancy Checkups Project) were collected, and their individual PM2.5 exposure values were estimated from the China National Environmental Monitoring Centre. The time of gestational exposure to PM2.5 was divided into four periods (the first trimester, the second trimester, the third trimester and the entire pregnancy). The average concentration and the corresponding quartiles of PM2.5 were calculated in these periods by the daily average PM2.5 data. Cox proportional hazards regression was used and he effects of maternal age, education level, occupation, second-hand smoking, alcohol use, pre-pregnancy BMI, babys sex, number of previous pregnancies, coastal areas and season of conception were adjusted for.nnnRESULTSnA total of 426,246 singleton births were included, among which 35,261 (8.3%) were preterm birth. Effect of each 10μg/m3 increase of PM2.5 on preterm birth was most significant during the third trimester (HR, 1.06; 95%CI, 1.06-1.07), and also significant during the first trimester (HR, 1.04; 95%CI, 1.03-1.04), the second trimester (HR, 1.02; 95%CI, 1.02-1.02) and the entire pregnancy (HR, 1.06; 95%CI, 1.05-1.06). Compared with the lowest quartile of PM2.5, other quartiles increased the risk of preterm birth, and were most significant during the third trimester (HR, 1.87; 95%CI, 1.69-2.06). Subgroup analysis showed that compared with other subgroups, women who were older than 30years, had low education level, worked as farmers, had male baby, had previous pregnancies, not live in coastal areas and pregnant in winter were more sensitive to PM2.5 exposure.nnnCONCLUSIONSnAmbient PM2.5 exposure during pregnancy played an important role in the pregnancy process and increased the risk of preterm birth.

Long-term exposure to fine particulate matter and tachycardia and heart rate: Results from 10 million reproductive-age adults in China

BACKGROUNDnEpidemiological evidence of the association of long-term ambient fine particulate matter (aerodynamic diameter ≤2.5u202fμm; PM2.5) exposure with resting heart rate is limited. We explored the association of long-term (3-year average) ambient PM2.5 exposure with tachycardia and resting heart rate.nnnMETHODSnThis cross-sectional study surveyed 10,427,948 reproductive-age (20-49 years) adults across China in 2015. Tachycardia was classified as a resting heart rate of >80 beats per minute (bpm). The annual average ambient PM2.5 concentrations were obtained from a hybrid satellite-based geophysical statistical model. Linear mixed models and mixed effects logistic regressions adjusted for potential confounding were performed to explore the associations of PM2.5 with resting heart rate and PM2.5 with tachycardia, respectively. The effect modifiers by sex, age, body mass index, urbanity, race, region, smoking status, and drinking status were also assessed. Attributable cases and population fraction were estimated according to the PM2.5- tachycardia relationship.nnnRESULTSnThe mean age was 28 years, and 16.3% of the participants had tachycardia. The odds ratio for tachycardia was 1.018 (95% confidence intervals [CI]: 1.017, 1.020) per 10u202fμg/m3 increase in the 3-year average PM2.5 exposure. A 10u202fμg/m3 increase in the 3-year average ambient PM2.5 level was associated with a 0.076 (95% CI: 0.073, 0.079) bpm elevation in the resting heart rate. Of the tachycardia burden, 4.0% (95% CI: 3.8%, 4.3%) could be attributed to ambient PM2.5 exposure in Chinese reproductive-age adults.nnnCONCLUSIONSnExposures to ambient PM2.5 were associated with elevated resting heart rate. It might be possible to decrease Chinas avoidable tachycardia burden in reproductive-age adults through decreasing PM2.5 levels.

Effect of airborne particulate matter of 2.5 μm or less on preterm birth: A national birth cohort study in China

BACKGROUNDnMost evidences regarding ambient PM2.5 or PM10 (particulate matter of median aerodynamic diameter ≤2.5u202fμm or ≤10u202fμm) and preterm birth (PTB) come from western countries which has relatively low PM pollution exposure, and the results are still inconsistent. This study aims to examine whether exposure to high concentrations of PM2.5 or PM10 was associated with PTB (<37u202fweeks) and near term birth (37-38u202fweeks).nnnMETHODnWe established a birth cohort with 1,280,524 singleton pregnancies who delivered from Dec 1st, 2013 to Nov 30th, 2014 and matched their home address to PM2.5 and PM10 concentrations which were predicted with machine learning methods based satellite remote sensing, meteorological and land use information. Cox proportional hazard regression models were used to analyze the associations between PTB and exposure of PM2.5 or PM10, after controlling for individual level covariates.nnnRESULTSnExposure to PM2.5 or PM10 during pregnancy increases the risk of PTB and near term birth [e.g., Hazard ratios: 1.09 (95% CI: 1.09, 1.10), 1.08 (95% CI: 1.07, 1.08), 1.01 (95% CI: 1.01, 1.02), and 1.09 (95% CI: 1.08, 1.10) for each 10u202fμg/m3 increase in PM2.5 for the 1st, 2nd, 3rd trimester and over the entire pregnancy, respectively]. The effects appeared to be stronger among women who come from rural areas, worked as farmers, were overweight before conception, whose mate was smoking during pregnancy, and conceived in autumn.nnnCONCLUSIONnThis study provides clear evidence that exposure to PM2.5 or PM10 during pregnancy increases the risk of PTB and near term birth. Public policies regarding improvement of air quality would produce great health benefit by reducing the burden of preterm birth.