Subclinical Cardiovascular Disease and Changes in Self-Reported Mobility: Multi-Ethnic Study of Atherosclerosis.

Background: We examined associations of three markers of subclinical cardiovascular disease (intimal-medial thickening, coronary artery calcification , and ankle-brachial index) with changes in self-reported walking over time.

Methods: Data were from 6,490 Multi-Ethnic Study of Atherosclerosis participants (aged 45-84 years), free of clinical cardiovascular disease at baseline. Outcomes, assessed four times over 11 years, included self-reported walking pace (none to striding pace; score, 0-4) and total walking time (minutes/week). Linear generalized estimating equation models estimated associations of baseline intimal-medial thickening (z-scored), coronary artery calcification (Agatston units), and ankle-brachial index (ratio of ankle-to-arm systolic blood pressure) with walking pace and walking time modeled continuously in separate analyses.

Results: Median follow-up was 9.2 years (maximum, 11.4). Walking pace (estimate, -0.042 points [95% CI; -0.048, -0.036], p < 0.0001) and walking time (estimate, -4.71 minutes [95% CI: -8.54, -0.88], p = 0.016) decreased yearly. Greater baseline intimal-medial thickening related to faster decline in walking pace in multivariable analyses: walking pace score decreased 0.004 points (95% CI: -0.008, -0.001) more per year for each 1-SD higher intimal-medial thickening z-score, equivalent to an additional 10% slower yearly walking. Greater coronary artery calcification was associated with slower walking but inconsistently related to decline in walking pace. Higher ankle-brachial index was associated with faster baseline walking pace (estimate, 0.043 points [95% CI: 0.027, 0.059] per 1-SD) but unrelated to changes in walking pace. Cardiovascular disease measures were unrelated to total walking time.

Conclusions: Greater subclinical cardiovascular disease is associated with prevalent slower self-reported walking pace in middle-aged and older adults but has limited impact on changes in walking over time.