Meta-analysis of the effects of indoor nitrogen dioxide and gas cooking on asthma and wheeze in children

Results A total of 41 studies met the inclusion criteria. The summary odds ratio from random effects meta-analysis for asthma and gas cooking exposure was 1.32 [95% confidential interval (CI) 1.18–1.48], and for a 15-ppb increase in NO2 it was 1.09 (95% CI 0.91–1.31). Indoor NO2 was associated with current wheeze (random effects OR 1.15; 95% CI 1.06–1.25). The estimates did not vary much with age or between regions. There was no evidence of publication bias.