Air Pollution and the Progression of Physical Function Limitations and Disability in Aging Adults.

Higher PM2.5 concentrations were associated with increased hazard of transitioning from no physical function limitations to physical function limitations.

• In the single-pollutant model, a 1-IQR higher PM2.5 concentration was associated with an HR of 1.06 (95% CI, 1.03-1.09) for transitioning from no physical function limitations to physical function limitations.
• Ten-year average ambient concentrations of PM2.5 were estimated at respondent residential addresses preceding each survey using spatiotemporal models.
• The sample included 29,790 respondents followed up for a mean (SD) of 8 (6) years.
• Multistate models adjusted for individual- and area-level covariates were used to examine associations.

Higher PM2.5 concentrations were associated with reduced likelihood of recovering from physical function limitations back to no limitations.

• A 1-IQR higher PM2.5 concentration was associated with an HR of 0.96 (95% CI, 0.93-0.99) for reverting back to healthy physical function from physical function limitations.
• This inverse association indicates that PM2.5 exposure hinders recovery as well as promotes progression toward disability.
• Physical disability states were assessed using self-reported mobility and Activities of Daily Living (ADL).

IQR-increments in PM10-2.5 and NO2 concentrations were mostly associated with greater hazards of transitioning from no physical function limitation toward disability.

• PM10-2.5 (particulate matter with diameter between 10 and 2.5 µm) and NO2 were both included as exposures alongside PM2.5 and O3.
• Ten-year average ambient concentrations of NO2 were estimated at respondent residential addresses using spatiotemporal models.
• Both single-pollutant and multi-pollutant models were used in analyses.

Higher ozone (O3) concentrations were associated with lower hazards of transitioning toward physical disability.

• A 1-IQR higher O3 concentration was associated with an HR of 0.92 (95% CI, 0.86-0.98) for transitioning from no physical function limitations to physical function limitations.
• A 1-IQR higher O3 concentration was associated with an HR of 0.89 (95% CI, 0.81-0.97) for transitioning from no physical function limitations to ADL disability.
• The direction of O3 associations was opposite to that observed for PM2.5, PM10-2.5, and NO2.

The study cohort was drawn from the nationally representative Health and Retirement Study and included adults older than 50 years followed from 2000 to 2016.

• The sample included 29,790 respondents with mean (SD) age of 63 (11) years.
• 56.7% of respondents were women (16,878); 11% were Hispanic (3,371), 18% non-Hispanic Black (5,240), and 68% non-Hispanic White (20,314).
• Respondents participated in at least 2 interviews and were followed up for a mean (SD) of 8 (6) years.
• Data analysis was conducted from July 2023 to August 2025.

The study employed a multistate modeling framework to capture both progression toward and recovery from physical disability states.

• Three disability states were modeled: no physical function limitation, physical function limitations, and ADL disability.
• Multistate models were adjusted for individual- and area-level covariates.
• The multistate approach allowed examination of bidirectional transitions, including recovery episodes following disability.
• Physical disability episodes can be followed by periods of recovery, motivating the need to identify modifiable risk factors affecting this dynamic process.