Exposure to household air pollution in relation to stomach and esophageal cancer in Xuanwei, China.

Household air pollution (HAP) is a global health burden affecting about half of the world's population. In Xuanwei, China, individuals experience high concentrations of various HAP constituents, particularly polycyclic aromatic hydrocarbons (PAHs). Here, the association between HAP constituents and cause-specific mortality from stomach and esophageal cancer was investigated. The study was conducted in a cohort of 42,420 subjects from Xuanwei, China. Participants were followed from 1976 to 2011. Type of fuel used was collected through a questionnaire and categorized into lifetime smoky vs. other fuel use. Annual exposures were predicted for 43 HAP constituents and 5 clusters were identified using hierarchical clustering. Cox regression was used to estimate the association between lifetime smoky coal use and pollutant clusters with stomach (n = 143) and esophageal (n = 39) cancer. All models were stratified by sex and birth cohort and adjusted for smoking status and education. Lifetime smoky coal use (hazard ratio [HR] = 1.40, 95 % confidence interval [CI]: 1.00, 1.96) and a large PAH cluster, PAH37 (HR = 1.59, 95 % CI: 1.19, 2.13 per standard deviation [SD]), were associated with stomach cancer mortality. Similarly, lifetime smoky coal use (HR = 2.84, 95 % CI:1.38, 5.85) and PAH37 (HR = 1.75, 95 % CI: 1.01, 3.04 per SD) were associated with esophageal cancer mortality. Stratified analyses found that the association between PAH37 and stomach cancer was higher among women compared to men (P-interaction = 0.02). This study identified an association between HAP and risk of stomach and esophageal cancer mortality in a highly exposed population. Future work is needed to investigate potential risk differences by timing of exposure.