Health effects from use of coal for cooking among Asian women

Abstract

Background: Coal continues to be used for indoor cooking in many parts of Asia, but the health consequences of exposure to coal combustion products have not been fully characterized. Methods: We analyzed the relationship between cooking with coal based on questionnaire data and all-cause and major categories of cause-specific mortality in the Shanghai Women’s Health Study (SWHS), a prospective cohort of about 75,000 primarily non-smoking females. We calculated hazard ratios (HRs) for coal use using Cox proportional hazards regression models adjusted for potential confounding factors including age, education, family income, occupational history, hormone therapy, parity, passive smoking, body mass index, and alcohol consumption. Results: Compared to never-coal users, ever use of coal for cooking was associated with an increase in mortality from all-causes (HR = 1.12; 95% confidence interval (CI) = 1.05-1.21), cancer (HR = 1.14; 95% CI = 1.03-1.27) and ischemic heart disease (HR = 1.35; 95% CI = 1.03-1.77), which was mainly driven by myocardial infarction (HR = 1.41; 95% CI = 1.00-2.00). Further, use of coal with poor ventilation was associated with increased risk of lung cancer (HR = 1.69; 95% CI = 1.22-2.35). In addition, we found evidence for gene-environment interactions between cooking with coal and risk of lung cancer. Conclusions: Our findings further characterize the health effects of coal use for household cooking among non-smoking women in Asia and provide insight into potential underlying mechanisms of action.