Long-term Air Pollution and Physical Disability in Older U.S. Adults: A Multi-State Modeling Evaluation from the EPOCH Study

BACKGROUND AND AIM[|]Physical disability reflects the cumulative burden of chronic conditions. It is also a dynamic process where episodes of disability can be followed by periods of recovery. Although air pollution is a well-established modifiable risk factor for chronic disease, its relationship with disability and the dynamics of disability is understudied. We investigated associations of air pollution exposure with transitions between health, mobility impairment, and physical disability.[¤]METHOD[|]We used biennial data from the nationally representative Health and Retirement Study between 2000 and 2016 on self-reported mobility and Activities of Daily Living (ADL). We estimated 10-year average concentrations of PM2.5, PM10-2.5, NO2, and O3 for respondent addresses using spatiotemporal models. To examine associations with transitioning between stages of physical disability, we employed multistate models adjusted for individual- and area-level confounders.[¤]RESULTS[|]Our sample included 29,790 respondents (average age: 63 years, 68% non-Hispanic White). We found that an interquartile range (IQR) larger PM2.5 concentration was associated with greater hazard of transferring from healthy to mobility impairment (HR: 1.06, 95% CI: 1.03, 1.09) and further continuing into ADL disability (HR: 1.05, 95% CI: 1.01, 1.09). NO2 was similarly associated with a 5% (HR: 1.05, 95% CI: 1.00, 1.09) greater hazard of mobility impairment and an 8% (HR: 1.08, 95% CI: 1.05, 1.11) greater hazard of continuing to ADL disability. There was also a greater hazard of transferring from healthy to ADL disability for PM2.5 (HR: 1.04, 95% CI: 1.01, 1.07) and NO2 (HR: 1.03, 95% CI: 0.98, 1.08). We also observed that higher PM2.5 and NO2 levels were associated with a 4% (HR: 0.96, 95% CI: 0.93, 0.99) and 3% (HR: 0.97, 95% CI: 0.94, 1.00) lower likelihood of transferring from mobility impairment to healthy, respectively.[¤]CONCLUSIONS[|]Our findings suggest that air pollution may accelerate the progression of physical disability and hinder recovery in later life[¤]