Preconception folic acid supplementation for the prevention of birth defects: a prospective, population-based cohort study in mainland China.

BACKGROUND: Folic acid supplementation is recommended for reducing the risk of birth defects. We aimed to assess the protective association of periconception folic acid supplements with birth defects in real-world setting. METHODS: This prospective, population-based cohort study utilized national preconception registered data of married Chinese couples planning a pregnancy within 6 months between 2010 and 2012 in Mainland China. Participated women are freely provided folic acid starting 3 months before conception till 3 months after conception. Birth defects were self-reported at 42 days postpartumn followup. R software (v4.0.2) was applied for statistical analyses. RESULTS: Complete data of 567,547 couples with pregnancy outcomes and folic acid supplementation were extracted for final analysis. A total of 74.7% women were with folic acid supplementation, and 599 birth defects were self-reported. The odd of birth defects was lower among women taking folic acid compared to their counterparts not taking (0.102% vs 0.116%, P < 0.001). In the multiple logistic regression analyses, the odd of birth defects was lower among couples with maternal folic acid supplementation (OR = 0.78, 95%CI: 0.66-0.95, P = 0.011), especially decreased odd of neural tube defects (NTDs) (OR = 0.56, 95%CI: 0.39-0.82, P = 0.003). This association was confirmed by 1:4 and 1:10 case control analysis. Odds of birth defects were significantly lower among women with folic acid supplementation more than 3 months before pregnancy (P < 0.001), and moreover, the odds of cleft (P = 0.007) and NTDs (P = 0.007) were of notable decrease. CONCLUSION: This retrospective case cohort study provides programmatic evidence for public health strategy-making to for reducing the risk of NTDs and clefts.

Association of Fine Particulate Matter and Its Components with Macrosomia: A Nationwide Birth Cohort Study of 336 Chinese Cities.

To examine the associations between macrosomia risk and exposure to fine particulate matter (PM2.5) and its chemical components during pregnancy, we collected birth records between 2010 and 2015 in mainland China from the National Free Preconception Health Examination Project and used satellite-based models to estimate concentrations of PM2.5 mass and five main components, namely, black carbon (BC), organic carbon (OC), nitrate (NO3-), sulfate (SO42-), and ammonium (NH4+). Associations between macrosomia risk and prenatal exposure to PM2.5 were examined by logistic regression analysis, and the sensitive subgroups were explored by stratified analyses. Of the 3,248,263 singleton newborns from 336 cities, 165,119 (5.1%) had macrosomia. Each interquartile range increase in concentration of PM2.5 during the entire pregnancy was associated with increased risk of macrosomia (odds ratio (OR) = 1.18; 95% confidence interval (CI), 1.17-1.20). Among specific components, the largest effect estimates were found on NO3- (OR = 1.36; 95% CI, 1.35-1.38) followed by OC (OR = 1.23; 95% CI, 1.22-1.24), NH4+ (OR = 1.22; 95% CI, 1.21-1.23), and BC (OR = 1.21; 95% CI, 1.20-1.22). We also that found boys, women with a normal or lower prepregnancy body mass index, and women with irregular or no folic acid supplementation experienced higher risk of macrosomia associated with PM2.5 exposure.

Folic Acid Supplementation and the Association between Maternal Airborne Particulate Matter Exposure and Preterm Delivery: A National Birth Cohort Study in China.

BACKGROUND: Potential modification of the association between maternal particulate matter (PM) exposure and preterm delivery (PTD) by folic acid (FA) supplementation has not been studied. OBJECTIVE: We examined whether FA supplementation could reduce the risk of PTD associated with maternal exposure to PM in ambient air during pregnancy. METHOD: In a cohort study covering 30 of the 31 provinces of mainland China in 2014, 1,229,556 primiparas of Han ethnicity were followed until labor. We collected information on their FA supplementation and pregnancy outcomes and estimated each participant's exposure to PM with diameters of ≤10µm (PM10), 2.5µm (PM2.5), and 1µm (PM1) using satellite remote-sensing based models. Cox proportional hazard regression models were used to examine interactions between FA supplementation and PM exposures, after controlling for individual characteristics. RESULTS: Participants who initiated FA ≥3 months prior to pregnancy (38.1%) had a 23% [hazard ratio (HR)=0.77 (95% CI: 0.76, 0.78)] lower risk of PTD than women who did not use preconception FA. Participants with PM concentrations in the highest quartile had a higher risk of PTD [HR=1.29 (95% CI: 1.26, 1.32) for PM1, 1.52 (95% CI: 1.46, 1.58) for PM2.5, and 1.22 (95% CI: 1.17, 1.27) for PM10] than those with exposures in the lowest PM quartiles. Estimated associations with a 10-µg/m3 increase in PM1 and PM2.5 were significantly lower among women who initiated FA ≥3 months prior to pregnancy [HR=1.09 (95% CI: 1.08, 1.10) for both exposures] than among women who did not use preconception FA [HR=1.12 (95% CI: 1.11, 1.13) for both exposures; pinteraction<0.001]. The corresponding association was also significantly lower for a 10-µg/m3 increase in PM10 [HR=1.03 (95% CI: 1.02, 1.03) for FA ≥3 months before pregnancy vs. 1.04 (95% CI: 1.03, 1.04) for no preconception FA; pinteraction<0.001]. CONCLUSION: Our findings require confirmation in other populations, but they suggest that initiating FA supplementation ≥3 months prior to pregnancy may lessen the risk of PTD associated with PM exposure during pregnancy among primiparas of Han ethnicity. https://doi.org/10.1289/EHP6386.

Socioeconomic inequality in periconceptional folic acid supplementation in China: a census of 0.9 million women in their first trimester of pregnancy.

BACKGROUND: To assess socioeconomic inequality in periconceptional folic acid supplementation in China. METHODS: We used data of periconceptional folic acid (FA) supplementation of rural Chinese women from the National Free Preconception Health Examination Project from 2010 to 2012 and socioeconomic level data from the National Bureau of Statistics. We used logistic models to assess the associations between the prevalence of taking FA and the sociodemographic characteristics of the participants, the couples, and the socioeconomic levels of their region of residence. RESULTS: Of the 907,720 included women, 682,315 (75.62%) of the women reported taking FA. The prevalence of FA supplementation was significantly higher in participants aged 21-29 (75.87%) than in those women aged 40-49 (68.44%, p < 0.01). The prevalence of FA supplementation was significantly higher in the region with the highest Per Capita Gross Regional Product than in the regions with lower Per Capita Gross Regional Product (aOR = 12.20 [95% CI:9.54-15.61]). The higher the per capita net income of farmer households in the region, the higher the prevalence of FA supplementation (aOR = 1.95 [95% CI:1.74-2.18]). CONCLUSIONS: The rate of periconceptional FA supplementation among rural Chinese women has increased with the support of China's Health System Reform policy. However, socioeconomic disparities in periconceptional folic acid supplementation remain.

Tissue microarrays in pathological examination of apoptotic acinar cells induced by dexamethasone in the pancreas of rats with severe acute pancreatitis.

BACKGROUND: The good therapeutic effects of large dose of dexamethasone on severe acute pancreatitis (SAP) patients have been proved. This study was designed to investigate the influence of dexamethasone on apoptosis of acinar cells in the pancreas of rats with SAP and the protein expression of the apoptosis-regulating genes Bax and Bcl-2. METHODS: Ninety Sprague-Dawley rats with SAP were randomly divided into a model group and a dexamethasone treated group (45 rats in each group), and another 45 rats formed the sham operation group. Survival rates were calculated and gross pathological changes in the pancreas of each group were observed under a light microscope 3, 6 and 12 hours after operation. Tissue microarray technology was applied to prepare pancreatic tissue sections. The changes in Bax and Bcl-2 protein expression levels of pancreatic tissues from each group were assessed by immunohistochemical staining, and TUNEL staining was used to evaluate changes in apoptosis index. RESULTS: The model and treated groups did not differ in mortality at each time point. The pathological score for the pancreas in the treated group was significantly lower than that in the model group at 3 and 6 hours. The positive rates of Bax protein expression in the head and tail of the pancreas in the treated group at all time points were all markedly higher than those of the model group. The positive rate of Bcl-2 protein expression in the head of the pancreas in the treated group was significantly higher than that of the model group at 3 hours. TUNEL staining showed that the pancreas head and tail apoptosis indices of the treated group were markedly higher than those of the model group after 6 hours. CONCLUSIONS: Apoptosis may be a protective response to pancreatic cell injury. The mechanism of action of dexamethasone in treating SAP may be related to the apoptosis of acinar cells in the pancreas induced by apoptosis-regulating genes such as Bax and Bcl-2. The advantages of tissue microarrays in pathological examination of the pancreas include saving of time and energy, efficiency and highly representative.