Exposure to cooking fuels and birth weight in Lanzhou, China: a birth cohort study

Min Jiang, Jie Qiu, Min Zhou, Xiaochun He, Hongmei Cui, Catherine Lerro, Ling Lv, Xiaojuan Lin, Chong Zhang, Honghong Zhang, Ruifeng Xu, Daling Zhu, Yun Dang, Xudong Han, Hanru Zhang, Haiya Bai, Ya Chen, Zhongfeng Tang, Ru Lin, Tingting Yao, Jie Su, Xiaoying Xu, Xiaohui Liu, Wendi Wang, Yueyuan Wang, Bin Ma, Weitao Qiu, Cairong Zhu, Suping Wang, Huang Huang, Nan Zhao, Xiaosong Li, Qing Liu, Yawei Zhang

Early studies have suggested that biomass cooking fuels were associated with increased risk of low birth weight (LBW). However it is unclear if this reduced birth weight was due to prematurity or intrauterine growth restriction (IUGR). In order to understand the relationship between various cooking fuels and risk of LBW and small for gestational age (SGA), we analyzed data from a birth cohort study conducted in Lanzhou, China which included 9,895 singleton live births. Compared to mothers using gas as cooking fuel, significant reductions in birth weight were observed for mothers using coal (weight difference = 73.31 g, 95 % CI: 26.86, 119.77) and biomass (weight difference = 87.84 g, 95 % CI: 10.76, 164.46). Using biomass as cooking fuel was associated with more than two-fold increased risk of LBW (OR = 2.51, 95 % CI: 1.26, 5.01), and the risk was mainly seen among preterm births (OR = 3.43, 95 % CI: 1.21, 9.74). No significant associations with LBW were observed among mothers using coal or electromagnetic stoves for cooking. These findings suggest that exposure to biomass during pregnancy is associated with risk of LBW, and the effect of biomass on LBW may be primarily due to prematurity rather than IUGR.