Air Pollution and Birth Outcomes in China – A Synthesis of Chinese and English Language Research
Background/Aim: Historically, the majority of research on air pollution and birth outcomes was undertaken on cohorts from western countries, with relatively lower levels of exposure. There is now a sufficient number of studies to warrant an assessment of effects in China, a higher exposure setting. This was the first systematic review of both Chinese and English language research on air pollution and birth outcomes in China. Methods: We conducted a systematic review, according to the PRISMA statement, of all Chinese and English language articles published between 1980 and 2015 on the association between ambient air pollution (NO2, SO2, CO, PM10, PM2.5, O3) and birth outcomes (low birth weight, preterm birth, stillbirth, congenital anomaly) in China. Of the 1,829 articles screened, 11 English language articles and 14 Chinese language articles were included for full review; 25 total. Results: Mean concentrations of PM10, NO2and SO2during the study period were 113μg/m3, 50μg/m3and 61μg/m3, respectively, with maximum concentrations of 600, 468 and 630μg/m3, respectively. Evidence of association with sulphur dioxide (SO2) was more consistently reported for reduced birth weight and preterm birth. Coarse particulate matter (PM10) was associated with congenital anomaly, notably cardiovascular defects. The adjusted odds ratio (95% CI) for pooled heart defects was 1.35 (1.15, 1.60) and ranged from 1.31 (1.07, 1.60) for patent ductus arteriosus to 1.44 (1.04, 1.99) for defects of the cardiac septa per 10 μg/m3 of PM10 over the entire pregnancy. Conclusions: Exposure levels and effects were generally greater in China. China has low incidence of some perinatal morbidities (e.g, preterm birth, 3%) but contributes substantially to global burden due to the large number of births (e.g.,1m preterm births per year), which might be addressed by reductions in sulphur dioxide and particulate matter.
Read more