The association between cooking oil fume exposure during pregnancy and birth weight: A prospective mother-child cohort study.

Effects of indoor air pollution on neonatal birth weight has been studied for many years. In China, cooking oil fumes are important parts of indoor air pollution. However, whether cooking oil fume exposure during pregnancy affects birth weight in China remains poorly understood. The objective of this study was to examine the association between pregnancy exposure to cooking oil fumes and birth weight in a newly established prospective mother-child cohort in China. We finally included 1420 pregnant women from 2013 to 2015 and follow up for one year until the offspring was born. According to self-reported exposure status, we categorized mothers into non-exposure group and exposed group or three exposure time subgroups, including 0h/day, 0-1h/day and >1h/day respectively. By using multinomial logistics regression models, we found that pregnancy exposure to cooking oil fumes significantly increased the risk of large for gestational age (LGA, OR=1.58, 95% CI=1.15-2.18, P=4.88×10-3 ). Additionally, compared to pregnant women who were in non-exposure group, 0-1h/day exposure elevated the risk of LGA (OR=1.69, 95% CI=1.22-2.33, P=1.63×10-3 ), while >1h/day exposure elevated the risk of small for gestational age, but were not significant (SGA, OR=2.15, 95% CI=0.61-7.66, P=0.24). In the stratification analysis, women aged 25-29years and ≥30years were predisposed to the influence of cooking oil fumes and have LGA newborns (OR=1.73, 95% CI=1.09-2.75, P=0.02; OR=1.72, 95% CI=1.07-2.77, P=0.02, respectively). In conclusion, the present study suggests inverse U-shape dose response association between maternal exposure to cooking oil fumes during pregnancy and birth weight, and further studies are needed to verify the effect of cooking oil fumes on the birth weight.