Reduced Lower Extremity Functioning Is Associated With an Increased Rate of Being a Nondriver: The National Health and Aging Trends Study

BACKGROUND: Driving a motor vehicle is an important aspect of mobility for older adults. Limited lower extremity functioning performance, as measured by the Short Physical Performance Battery (SPPB), has been associated with various negative health outcomes, but little is known about the association of SPPB scores with driving status. OBJECTIVE: The purpose of this study was to evaluate whether lower (poorer) SPPB scores are associated with an increased rate for being a current nondriver among a nationally representative sample of community-dwelling older adults. DESIGN: The National Health and Aging Trends Study is a longitudinal cohort study. METHODS: A population of 5935 participants, surveyed annually from 2011 to 2014 for the National Health and Aging Trends Study, was used to examine the relationship between SPPB and driving status. Using weighted data, multivariable Poisson regression with generalized estimating equations was used to calculate the rate ratios, adjusting for covariates and clustering due to the complex survey design. RESULTS: Participants with a low (poor) SPPB score (0-5) had a rate for being a current nondriver 2.01 times the rate (or 101% increase) of those with a high (good) SPPB score (10-12) (adjusted 95% confidence interval = 1.78-2.26). LIMITATIONS: Current nondrivers were not asked whether they planned to resume driving if they had not driven in the previous year. CONCLUSIONS: Unlike other factors, such as cognitive decline, lower SPPB scores (poorer lower extremity functioning) are significantly associated with an increased rate of being a current nondriver and are a modifiable risk factor. Further research is needed to examine whether optimum exercises and other physical therapist interventions focused on improving lower extremity strength and balance ultimately improve driving outcomes.