Joint effects of prenatal household air pollution exposure from multiple sources on preterm birth - A case-control study with propensity score matching

Abstract Prenatal exposure to household air pollution (HAP) has been suggested as a major risk factor for preterm birth (PTB). However, the effects of simultaneous prenatal exposure to multiple HAP sources on PTB have rarely been studied. We therefore conducted a case-control study on 21995 mother-child dyads after propensity score matching (PSM). After PSM, a series of logistic regression analysis on associations of environmental tobacco smoke (ETS), cooking oil fumes (COFs), burning mosquito coil (BMC), indoor burning incense (IBI) and household renovation (HR) with PTB were conducted to evaluate their independent and joint effects on PTB. Compared to mothers without exposure, prenatal exposure to each individual HAP source increased the PTB risk. Moreover, the accumulative effects of prenatal exposure to five sources of HAP on the risk of PTB were observed. Finally, we found synergistic effects between prenatal exposure to COFs and IBI, as well as between BMC and IBI, on PTB on both multiplicative and additive scales. Our results suggest that prenatal exposure to different sources of HAP might increase the risk of PTB and that accumulative effects, as well as synergistic interactions, between different HAP sources on PTB might exist.