Association between household air pollution from solid fuel use and risk of chronic diseases and their multimorbidity among Chinese adults

Given the increasing burden of chronic conditions, multimorbidity is now a priority for public health systems worldwide. However, the relationship between household air pollution (HAP) exposure with multimorbidity remains unclear.We used three waves data (2011, 2013, and 2015) including 19,295 participants aged ≥ 45 years from the China Health and Retirement Longitudinal Study, to investigate the association between HAP exposure from solid fuel use for heating and cooking with the risk of chronic multimorbidity. Multimorbidity was defined as the coexistence of two or more of 15 chronic diseases (hypertension, diabetes, dyslipidemia, heart disease, stroke, cardiovascular disease, chronic lung disease, asthma, kidney disease, liver disease, digestive disease, cancer, psychiatric disease, memory-related disease, and arthritis). Multiple logistic regression investigated the association between solid fuel use for heating and cooking, separately or simultaneously, with the risk of multimorbidity. Poisson regression with quasi-likelihood estimation explored whether solid fuel exposure could increase the number of morbidities. Stratified analyses and sensitivity analyses examined the effect modification and robustness of the association.Of the 19,295 participants (mean age: 58.9 years), 40.9 % have multimorbidity. Compared with participants who used clean fuels for heating and cooking, the risk was higher in mixed fuel (adjusted odds ratio, aOR = 1.26, 95 %CI:1.16-1.36) and solid fuel users (aOR = 1.81, 1.67-1.98) separately. HAP from solid fuel use was positively associated with an increased number of morbidities (adjusted β = 0.329, 0.290 to 0.368), after controlling for confounders. Those living in a one-story building, with poor household cleanliness have a higher risk of multimorbidity. No significant modifications of those associations by the socio-demographic and behaviour characteristics was observed.HAP from solid fuel use is associated with a high risk of chronic multimorbidity in Chinese adults. Our findings provide important implications for reducing chronic disease burden by restricting solid fuel use.