Principal Investigator: Erica Twardzik
K99/R00 AG081563 
NIH Reporter listing 

11.2 million (23.5%) older adults report difficulty traveling outside their homes, making limited transportation access a structural barrier to health. With over 7 million non-driving older adults and 7-10 non-driving years at the end of life, alternative transportation options are needed. Lack of public transit accessibility can disproportionally harm older adults with disabilities and may impact health behaviors, such as physical activity and social participation. Physical activity and social participation are key components of healthy aging, associated with cognition, quality of life, and mortality. To this end, identification of modifiable public transit features, and their impact on physical activity and social participation among older adults with disabilities is critically needed. 

The proposed research will examine the role of public transit on physical activity and social participation among older adults with and without disabilities. This research will collect primary data on public transit accessibility features and link them to the National Health and Aging Trends Study. Specifically, this research will address the following aims: 

1. Examine if self-reported public transit use is associated with physical activity and social participation among older adults with and without disabilities,
2. Determine if the accessibility of public transit systems is associated with physical activity and social participation behaviors among older adults,
3. Test the hypotheses that public transit use partially mediates the link between public transit features and (a) physical activity and/or (b) social participation among older adults. 

The proposed use of NHATS, a rich, integrated data source, will allow for investigation into whether public transit use interacts with disability status to result in differential physical activity and social participation (Aim 1); if the density and accessibility of public transit systems interact with disability status to affect physical activity and social participation (Aim 2); and the mechanism through which disability, public transit features, and public transit use shape physical activity and social participation among older adults (Aim 3). This research will examine if public transit system access is associated with physical activity and social participation among older adults with disabilities, a potential intervention target to optimize older adults’ ability to age in place. Identification of modifiable, upstream factors could reduce health disparities among this population group. The findings from this work will inform transportation development and planning about public transit systems which are inclusive of older adults with disabilities.