Prevalence of Underweight, Overweight, and Obesity Among Reproductive-Age Women and Adolescent Girls in Rural China.

OBJECTIVES: To provide prevalence and trends of underweight, overweight, and obesity among reproductive-age women and adolescent girls in rural China. METHODS: We measured weight and height in 16 742 344 women aged 20 to 49 years and 178 556 girls aged 15 to 19 years from the National Free Preconception Health Examination Project between 2010 and 2014. RESULTS: Among women, the prevalence of underweight was 7.8% (95% confidence interval [CI] = 7.7%, 7.9%), and overweight or obesity was 16.5% (95% CI = 16.4%, 16.6%; World Health Organization criteria). Among adolescents, prevalence of underweight was 6.0% (95% CI = 5.7%, 6.2%; Centers for Disease Control and Prevention criteria) and overweight or obesity was 8.3% (95% CI = 7.9% to 8.8%; International Obesity Task Force criteria). According to Chinese criteria, overweight and obesity prevalence was 24.8% (95% CI = 24.7%, 24.9%) for women and 17.2% (95% CI = 16.6%, 17.8%) for adolescents, and underweight prevalence was 2.9% (95% CI = 2.8%, 3.1%) for adolescents. Considerable disparities existed in prevalence and trends within subpopulations (age groups, parity, region, education levels, and socioeconomic status). CONCLUSIONS: Our results reveal coexisting underweight and overweight or obesity among rural women and adolescents of reproductive age, which requires public health attention.

Association Between Body Mass Index and Mildly Decreased Estimated Glomerular Filtration Rate in Chinese Adults With Early Chronic Kidney Disease.

OBJECTIVES: The magnitude of the influence that obesity contributes to the early stage of chronic kidney disease, especially among Asian population with higher obesity-related health risk, is unclear. The aim of this study was to investigate the association between body mass index (BMI) and mildly decreased estimated glomerular filtration rate (eGFR) among Chinese population. DESIGN AND METHODS: A cross-sectional study was conducted among 1,100 subjects under health screenings. BMI was used to classify overweight and obesity as a BMI greater than or equal to 23.0 kg/m2 and 25.0 kg/m2, respectively. Mildly decreased eGFR was defined as 60.0 to ≤89.0 mL/min/1.73 m2 based on modification of diet in renal disease Chinese equation. RESULTS: The prevalence of mildly decreased eGFR was increased significantly with increasing BMI categories. According to modification of diet in renal disease Chinese equation, obesity (odds ratio, 1.83; 95% confidence interval: 1.15-2.90) was positively associated with the odds of mildly decreased eGFR in the multivariate logistic regression model. BMI was significantly and negatively related to eGFR, and each increase in BMI (1.0 kg/m2) was associated with a decline in eGFR of 0.5 mL/min/1.73 m2. In subgroup analyses, BMI remained associated with an increased likelihood of mildly decreased eGFR independent of hypertension and diabetes. CONCLUSIONS: There was a positive relationship between BMI and mildly decreased eGFR among Chinese adults. Higher BMI may play a role in the onset and progression of renal damage, and maintaining a BMI in the healthy range may be contributed to the prevention of chronic kidney disease.

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

BACKGROUND: With 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. OBJECTIVES: To investigate the association between exposure to extreme temperatures and preterm birth. METHODS: Temperature 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. RESULTS: A 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. CONCLUSIONS: Acute 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.

Effect of folic acid supplementation on preterm delivery and small for gestational age births: A systematic review and meta-analysis.

OBJECTIVE: To investigate the effect of folic acid (FA) supplementation on the risks of preterm delivery (PTD) and small for gestational age births (SGA). DATA SOURCES: Cohort studies were identified from MEDLINE, EMBASE, the Cochrane Library, CINAHL, and CBM from inception to January 2015. PARTICIPANTS AND INCLUDED STUDIES: Healthy women who want to get pregnancy or being pregnant. MAIN OUTCOME MEASURES: PTD and SGA. RESULTS: The association of FA and PTD was significant when supplement initiated after pregnancy (RR=0.68, 95%CI, 0.52-0.90), whereas no effect was founded if the initiation time was before conception (RR=0.89, 95%CI, 0.80-1.01). The results for the association between FA supplementation and SGA showed significant protective effect: initiated before conception (RR=0.70, 95%CI, 0.57-0.85) and initiated after conception (RR=0.84, 95%CI, 0.81-0.89). CONCLUSION: Folic acid supplementation is associated with a significant reduction on the risk of PTD when initiated after conception. It can also protect fetus from SGA.

Prevalence of overweight and obesity in 15.8 million men aged 15-49 years in rural China from 2010 to 2014.

Obesity has been increasing worldwide. Data on obesity status among men of reproductive age are scarce. This study aimed to assess the national prevalence and trend of overweight and obesity among reproductive-age men in rural China. In the nationwide population-based study, data were obtained from the National Free Preconception Health Examination Project in rural China from 2010 to 2014. Weight and height were measured in 16 161 982 men aged 15-49 years and their female partners (15 997 739 participants aged 15-49 years) before conception, and body mass index (BMI) was calculated. We found that the prevalence of combined overweight and obesity among men was 33.8% (33.7-33.9%) according to Chinese criteria (BMI ≥ 24.0 kg/m2), the corresponding rates of obesity were 6.3% (6.2-6.4%; BMI ≥ 28.0 kg/m2), respectively. The prevalence varied in different ethnic groups, geographic regions, age, education and GDP levels, and increasing trend was observed over the 5-year study period. In addition, 45.8% of couples had at least one of them as overweight or obesity. About one third of men aged 15-49 years before conception in rural China are overweight or obese. Overweight/obesity clusters in families, which highlights the importance of family involvement of early prevention of obesity in China.

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 wife's hypertension has not been well studied. The current study was aimed to assess the association of husband smoking with wife's 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 (Pfor 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.

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 (+) (AOR = 2.61), HBeAg(-)/HBsAg (+) (AOR = 2.23), positivity of syphilis (AOR = 1.50), living in a high-risk region (AOR = 1.46) 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.