Association between household air pollution from solid fuel use and respiratory health: Results from two national prospective cohort studies

Previous studies have shown that household air pollution (HAP) from solid fuel use affects respiratory health, but few have explored the mechanisms associated with chronic respiratory diseases (CRDs). In this study, we investigated the association between HAP and CRDs using CHARLS and MHAS data, employing time varying Cox models. Among 10,919 CHARLS participants and 11,147 MHAS participants, approximately 56 % and 12 % of them reported exposure to HAP, respectively. Individuals with HAP exposure from solid fuel use had higher CRDs risk (CHARLS: hazards ratio [HR]= 1.305 [95 % confidence interval {CI}: 1.156, 1.473], MHAS: HR= 1.244 [95 % CI: 1.038, 1.491]). In addition, compared with the exposure pattern of "all clean fuels", the "alternate-use clean and solid fuels" pattern and the "all solid fuels" pattern were associated with increased risk of CRDs. In joint analysis, compared with those never smokers using clean fuels, smokers using solid fuels (HR=1.750, 95 % CI: 1.429, 2.145, P < 0.001) had a higher risk of CRDs. Arthritis, depression, and body mass index may partially mediate the relationship between HAP exposure from solid fuel use and CRDs. Population attributable risk due to HAP exposure from solid fuel use was 3 % - 14 %. In conclusion, HAP exposure from solid fuel use was associated with an increased risk of CRDs.