Longitudinal Associations Between Changes in Physical Function and Driving Mobility Behaviors of Older Adults.

Objectives: To examine time-varying correlations between multiple indices of physical function and driving mobility in older adults across five years.

Design: Longitudinal.

Participants: Older drivers aged 65-91 = 73.6 ± 5.78) who were randomly assigned to the no-contact control arm of the Advanced Cognitive Training for Independent and Vital Elderly study ( = 598).

Measurements: The driving mobility outcomes were self-reported driving space, driving exposure, driving frequency, and weekly mileage assessed at baseline, and first, second, third, and fifth follow-up visits. Physical functioning measures included grip strength, the Turn360 test, and self-reported physical function. Multilevel models examined relationships between changes in physical functioning and driving mobility outcomes over five years.

Results: Driving space and driving frequency decreased over time, especially for older individuals. Changes in physical function were positively related to changes in driving mobility after controlling for demographics, attrition, baseline cognitive function and visual acuity, and changes in general health. Patterns of associations varied depending on the specific physical function measure and mobility outcome.

Conclusions: The findings highlight the time-varying nature of the relationships between physical functioning and driving mobility. Further research is needed to fully understand dynamic associations between driving mobility and key components of mobility that vary over time.