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

Abstract

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 (M = 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 (N = 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.

Association of Physical Function With Driving Space and Crashes Among Older Adults

“…The LongROAD study is collecting objective data such as global positioning system (GPS) information, police reports, driving records, visual perception functioning assessments, and medical records, which can be used in further analysis to confirm this study's findings. Additionally, future analysis of the longitudinal data collected by the LongROAD study can establish the causal effects of lower SPPB on driving mobility and safety and examine potential time-varying associations (Phillips et al, 2016).…”

“…We selected covariates as potential confounders a priori, including gender, age, education, marital status, selfreported vision, driving importance, depression, anger, cognitive health, miles driven per week, and days driven per week. Based on previous study findings of gender differences in SPPB scores, driving mobility and driving exposure, we selected gender as a potential effect modifier of the association between physical functioning and both outcomes (Guralnik et al, 1994;Phillips et al, 2016;Ross et al, 2009).…”

“…A priori confounders known to affect driving outcomes (gender, age, depression, cognitive health, and miles driven per week) were kept in the models as confounders and the remaining covariates were evaluated for evidence of confounding using a change-in-estimate method (Anstey et al, 2005;Greenland, 1989;Hill et al, 2017;Owsley et al, 1999;Phillips et al, 2016;Rolison & Moutari, 2018;Turano et al, 2009). We deleted each variable individually from an initial model that included all covariates and included in the final model only covariates that changed the SPPB parameter estimate by at least 10%.…”

“…Previous research on older adults has investigated whether physical function is associated with driving space (a measure of driving mobility) and crashes, but findings so far have been inconsistent. For example, in a longitudinal study, self-reported driving space across 5 years was not associated with either the Turn 360 Test (a measure of lower limb strength and balance), or self-reported physical functioning, but was associated with grip strength (Phillips, Sprague, Freed, & Ross, 2016). However, Vance et al (2006) demonstrated that among individuals 55 years of age and older, lower extremity function, as measured by a composite of the Rapid Pace Walk (a measure of lower limb mobility through walking and turning) and the Foot Tap test did not predict a composite variable of driving space within the last year, number of days driven per driven, miles driven per week and miles driven per year.…”

Velocidade da Marcha e Força de Preensão Manual: Indicadores das Condições Físicas de Idosos Submetidos à Avaliação para Habilitação Veicular

“…Mudanças na força de preensão foram associadas positivamente com alterações no espaço de condução (estimativa=0,12, p<0,05), de modo que, para cada diminuição de quilograma na força de preensão, houve uma diminuição de 0,12 nas unidades de espaço de condução (Phillips et al, 2016).…”