Indoor air pollution and frailty: A cross-sectional and follow-up study among older Chinese adults

Previous studies have suggested that ambient air pollution negatively affects frailty, but whether indoor air pollution exposure affects frailty is unknown.This study was conducted on 4946 older adults (≥60 years) followed from baseline to 4 years in the Chinese Longitudinal Healthy Longevity Survey. Household fuel types and frailty were assessed with self-rated questionnaires and physical examination. The relationships between indoor air pollution and frailty via phenotypic frailty and a frailty index were explored with logistic regression models and Cox proportional hazard regression models in both a cross-sectional and follow-up design. Additionally, the effects of indoor air pollution on phenotypic frailty together with mild cognitive impairment (MCI) were further investigated.In the cross-sectional study, the adjusted ORs (95% CIs) for frailty assessment with the frailty index and phenotypic frailty were 1.28 (1.12, 1.46) and 1.36 (1.18, 1.57), respectively. Solid fuel use was a risk factor in prefrail/frail patients with [OR and 95% CI, 1.88 (1.41, 2.50)], or without MCI [OR and 95% CI, 1.37 (1.17, 1.61)], as compared with the groups with no phenotypic prefrailty/frailty and no MCI. Moreover, solid cooking fuel use was positively associated with the incidence of phenotypic prefrailty and frailty. The adjusted HRs (95% CIs) for phenotypic prefrailty and frailty were 1.26 (1.03, 1.55).Solid cooking fuels can be regarded as a risk factor for frailty. Moreover, our findings suggest that more attention should be paid to solid cooking fuel using as it relates to phenotypic frailty together with MCI.