Air pollution may promote functional limitations in older adults

Long-term exposure to ambient air pollution contributes to an increased risk of physical disability and hamper recovery in older adults, as reported in a study.

The study included 29,790 participants older than 50 years (mean age 63 years, 57 percent female, 68 percent non-Hispanic White) from the nationally representative Health and Retirement Study. These participants completed at least two interviews during a mean follow-up of 8 years.

Spatiotemporal model was used to estimate 10-year average ambient concentrations of particulate matter (PM) with a diameter of ≤2.5 µm (PM2.5), PM with a diameter between 10 and 2.5 µm (PM10-2.5), nitrogen dioxide (NO2), and ozone (O3) at respondent residential addresses preceding each survey. Physical function was evaluated using self-reported mobility and Activities of Daily Living (ADL).

Analyses indicated that interquartile (IQR) increments in PM2.5, PM10-2.5, and NO2 concentrations were associated with an increased risk of transitioning from a state of no physical function limitation toward disability. Furthermore, each 1-IQR increment in PM2.5 was associated with reduced odds of a reverse transition.

For instance, in the single-pollutant model, each 1-IQR higher PM2.5 concentration was associated with a 6-percent increased risk of transitioning from a no-physical-function-limitation state to physical function limitations (hazard ratio [HR], 1.06, 95 percent CI, 1.03–1.09), as well as a 4-percent lower likelihood of reverting to healthy physical function from physical function limitations (HR, 0.96, 95% CI, 0.93–0.99).

Meanwhile, each 1-IQR higher O3 concentration was associated with a lower risk of transitioning from no physical function limitations to physical function limitations (HR, 0.92, 95 percent CI, 0.86–0.98) and ADL disability (HR, 0.89, 95 percent CI, 0.81–0.97).

These findings suggest that reducing certain key air pollutants may help delay the onset of physical function limitations and ADL disability, as well as mitigate the severity of physical disability even after the process began.