Air pollution predicts healthcare spending among older adults in the United States

Air pollution is associated with poor health, including chronic diseases, cognitive declines, and physical limitations in late life. The financial burdens of these exposures are likely underestimated due to a reliance on indirect estimates not generated by individual-level data and the exclusion of out-of-pocket expenses and long-term care costs.

We used repeated measures of Medicare-linked survey data from respondents in the Health and Retirement Study (HRS), a nationally-representative, population-based, cohort study in the United States. We included all respondents aged ≥ 67 years who were enrolled in fee-for-service coverage between 2006 and 2016 to characterize associations between air pollution and Medicare and out-of-pocket healthcare spending. We estimated 10-year average concentrations of four key air pollutants (PM_2.5, PM_10-2.5, NO₂, O₃) for each respondent using residential histories and spatiotemporal models. We summarized Medicare and out-of-pocket (OOP) spending ($2016) for medical services, personal services, and prescription drugs for each respondent per month. Associations between 10-year average air pollution and monthly healthcare spending were assessed per interquartile range of exposure using linear and quantile regression, adjusting for confounding and accounting for survey design.

Among 11,160 respondents (72 ± 7yrs), the mean annual total healthcare spending in Medicare and out-of-pocket spending were $16,680 and $3,156, respectively. Higher levels of PM_10-2.5 and NO₂ were associated with upward shifts in annual healthcare spending with $614 (95% CI: $324, $904) and $1,047 (95% CI: $580, $1,515) higher spending at the 90th percentile and $138 (95% CI: $113, $163) and $162 (95% CI: $123, $201) higher median spending, respectively. In contrast, associations with PM_2.5 were not robust to the adjustment of co-pollutants, and O₃ was associated with lower spending.

Interventions to reduce PM_10-2.5 and NO₂ may mitigate societal and personal healthcare spending for older adults, particularly for those with high medical needs.