Pain in Solid and Clean Fuel Using Households

Household air pollution from solid cooking fuel use influences multiple health outcomes, but its association with body pain remains poorly understood. This was a longitudinal study of 8880 adults who participated in the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018. Household cooking fuels were extracted from the baseline household questionnaire. Transitions in cooking fuels from 2011 to 2018 were also identified. Body pain status was reported in the three waves of surveys conducted in 2011, 2015, and 2018. The associations between cooking fuel type, fuel transition, and pain site number were examined using generalized estimating equations. Among the 8880 participants, 41.4% ( $n=3680$ ) primarily used clean fuels for cooking, and 58.6% ( $n=5200$ ) used solid ones at baseline. Cooking with solid fuels was associated with more pain sites (incidence rate ratio (IRR): 1.14; 95% confidence interval (CI): 1.08 to 1.21), but a slower rate of pain sites increases from 2011 to 2018 ( $\text{IRR}=0.78$ ; 95% CI: 0.71 to 0.86, for $2018\times \text{solid}$ fuels). Compared with those who persistently used clean fuels for cooking, the number of pain sites increased by 10% in participants who transiting from using solid to clean fuels ( $\text{IRR}=1.10$ ; 95% CI: 1.04 to 1.18), by 21% in those transiting from cooking with clean to solid fuels ( $\text{IRR}=1.21$ : 95% CI: 1.08 to 1.35) and by 25% among those persistent using solid fuels for cooking ( $\text{IRR}=1.25$ ; 95% CI: 1.18 to 1.34). Our findings provided new evidence linking using solid fuels for cooking with more pain sites, but a slower rate of pain sites increases. Public health efforts should focus on fuel transition and take measures to help clean fuels spread.