Household solid fuel use and the risk of sarcopenia among middle-aged and older adults in China: the first nationwide cross-sectional and longitudinal study

BackgroundLittle is known about the association between household solid fuel use and sarcopenia risk. Using a nationally representative survey, we investigated the association between solid fuel used for heating and cooking and sarcopenia risk among middle-aged and older Chinese adults. MethodsWe leveraged two waves of data from the China Health and Retirement Longitudinal Study (CHARLS); 12,723 participants aged [≥] 45 years from 28 provinces across China were enrolled in 2011. Sarcopenia status was classified according to the Asian Working Group for Sarcopenia 2019 criteria. A total of 3,110 participants without sarcopenia were recruited at baseline and were followed up until 2013. Primary fuel types and durations used for heating and cooking were assessed using a validated questionnaire. Multinomial logistic regression explored the cross-sectional and longitudinal associations between solid fuel use and different stages of sarcopenia. FindingsThe prevalence of possible sarcopenia and sarcopenia were 34{middle dot}8% and 5{middle dot}7%, respectively. Compared with clean fuel users, those using solid fuel for both heating and cooking had significantly higher risks of possible sarcopenia (odds ratio, [OR] 1{middle dot}72, 95%CI: 1{middle dot}54-1{middle dot}91) and sarcopenia (OR 1{middle dot}74, 1{middle dot}31-2{middle dot}31). During the two-year follow-up, 569 participants (18{middle dot}3%) developed with possible sarcopenia and 86 (2{middle dot}8%) had sarcopenia. In the longitudinal analyses, solid fuel use was positively associated with the risk of possible sarcopenia (OR 1{middle dot}75, 1{middle dot}32-2{middle dot}31), and the association was higher in individuals with a longer duration of solid fuel use. However, no significant association was observed with the incidence of sarcopenia. Older adults, with less physical activity might have a higher risk of sarcopenia when exposed to solid fuel. InterpretationHousehold solid fuel is associated with a higher risk of sarcopenia among middle-aged and older Chinese adults. These findings provide novel evidence for prioritizing public health policies to promote healthy aging by reducing solid fuel use. FundingNational Natural Science Foundation of China Research in contextO_ST_ABSEvidence before this studyC_ST_ABSWe searched PubMed, Google Scholar, and the China National Knowledge Infrastructure for studies published in English and Chinese up to February 1, 2023. We used the search terms ("sarcopenia") AND ("solid fuel" OR "biomass fuel" OR "coal" OR "air pollution") and found a recent study that explored the cross-sectional relationship between ambient air pollution and sarcopenia risk in the UK. However, no large population-based study has investigated the effects of household solid fuel use on sarcopenia. Added value of this studyOur study showed for the first time that household solid fuel use is associated with a higher risk of sarcopenia among middle-aged and older Chinese adults. Our findings provide important prospective evidence linking solid fuels to an increased risk of sarcopenia. Reducing solid fuel use can be beneficial in preventing sarcopenia and promoting healthy aging in older adults. To our knowledge, this study is the largest nationwide cross-sectional and longitudinal study to date investigating the association between household fuel types and duration of solid fuel use with different stages of sarcopenia. Implications of all the available evidenceOur findings underscore the importance of improving access to clean fuels to reduce the risk of sarcopenia associated with cooking and heating fuel use. This study extends the knowledge that prioritizes public health policies to mitigate the adverse effects of solid fuel use on sarcopenia and provides implications for further mechanistic research.