The impact of airborne particles and ozone on cognition, mobility, and health care spending at older ages: Evidence from a nationally-representative longitudinal cohort
Declines in cognitive function and mobility are common in older age, arising from a combination of subclinical pathologies and chronic disease across multiple organ systems. Early onset of these declines can result in substantial personal limitations and financial costs. Importantly, these consequences of aging vary among people, ranging in severity from minor functional limitations with minimal interference in typical activities to dementia and more extensive physical disability that impair self-care activities and independent living. Although there is substantial interest in preventing or postponing cognitive and mobility impairments and the associated health care costs, prevention efforts have been frustratingly slow. The central hypothesis of this project is that air pollution is a likely, but largely unexplored, modifiable risk factor for poor cognition and mobility as well as greater health care spending in older ages. This hypothesis is based on evidence that air pollutants enter the blood stream, translocate into the brain, and initiate systemic cellular changes that often lead to subclinical, preclinical, and then, chronic disease. The accumulation of subclinical and clinical disease across all organ systems ultimately increases the risk of cognitive and mobility impairments as well as the more serious clinical manifestations of dementia and physical disability. Collectively, the likely result is greater health burdens and health care spending at older ages. To test our hypothesis, we will newly predict individual-level air pollution concentrations for each Health and Retirement Study (HRS) respondent using a state-of-the-art national exposure model. The HRS is a nationally-representative cohort of over 37,500 older adults followed for more than 20 years with detailed biennial data on cognitive function, dementia, mobility, disability, and health care expenditures. Thus, this project will create an unparalleled data source to comprehensively assess the longitudinal associations of long-term air pollution exposures with cognition, mobility, and health care spending. Specifically, our aims are to: 1) Prospectively determine the associations of individual-level, long-term concentrations of fine (PM2.5) and coarse particulate matter (PM10-2.5) and ozone (O3) with cognition and mobility in older ages; 2) Directly estimate associations of individual-level, long-term concentrations of PM2.5,PM10-2.5, and O3 with public and personal health care spending in older ages; and 3) Quantify the excess dementia and disability cases and economic costs from health care spending attributable to long-term exposures to PM2.5, PM10-2.5, and O3 among older adults in the United States. This proposed research is highly innovative because it newly examines associations between air pollution and two key consequential outcomes of aging as well as public and personal health care costs in older ages. Given that the HRS is a large, prospective, and nationally-representative survey with respondents experiencing the full range of air pollution concentrations in the United States, this research is expected to have a large public health impact by informing policy makers on a modifiable exposure to improve health and limit health care spending in older ages.
National Institute of Environmental Health Sciences
Funding Period: 9/1/2018 to 8/31/2022