Supplementary Material for: Physical Inactivity Predicts Slow Gait Speed in an Elderly Multi-Ethnic Cohort Study: The Northern Manhattan Study

<p><b><i>Introduction:</i></b> Gait speed is associated with multiple adverse outcomes of aging. We hypothesized that physical inactivity would be prospectively inversely associated with gait speed independently of white matter hyperintensity volume and silent brain infarcts on MRI. <b><i>Methods:</i></b> Participants in the Northern Manhattan Study MRI sub-study had physical activity assessed when they were enrolled into the study. A mean of 5 years after the MRI, participants had gait speed measured via a timed 5-meter walk test. Physical inactivity was defined as reporting no leisure-time physical activity. Multi-variable logistic and quantile regression was performed to examine the associations between physical inactivity and future gait speed adjusted for confounders. <b><i>Results:</i></b> Among 711 participants with MRI and gait speed measures (62% women, 71% Hispanic, mean age 74.1 ± 8.4), the mean gait speed was 1.02 ± 0.26 m/s. Physical inactivity was associated with a greater odds of gait speed in the lowest quartile (<0.85 m/s, adjusted OR 1.90, 95% CI 1.17-3.08), and in quantile regression with 0.06 m/s slower gait speed at the lowest 20 percentile (<i>p</i> = 0.005). <b><i>Conclusions:</i></b> Physical inactivity is associated with slower gait speed independently of osteoarthritis, grip strength, and subclinical ischemic brain injury. Modifying sedentary behavior poses a target for interventions aimed at reducing decline in mobility.</p

Supplementary Material for: Regional Subclinical Cerebrovascular Disease Is Associated with Balance in an Elderly Multi-Ethnic Population

<b><i>Introduction:</i></b> White matter hyperintensity volume (WMHV) and subclinical brain infarcts (SBI) are associated with impaired mobility, but less is known about the association of WMHV in specific brain regions. We hypothesized that anterior WMHV would be associated with lower scores on the Short Physical Performance Battery (SPPB), a well-validated mobility scale. <b><i>Methods:</i></b> The SPPB was measured a median of 5 years after enrollment into the Northern Manhattan MRI sub study. Volumetric distributions for WMHV in 14 brain regions as a proportion of total cranial volume were determined. Multi-variable linear regression was performed to examine the association of SBI and regional log-WMHV with the SPPB score. <b><i>Results:</i></b> Among 668 participants with SPPB measurements (mean 74 ± 9 years, 37% male and 70% Hispanic), the mean SPPB score was 8.2 ± 2.9. Total (beta = –0.3 per SD, <i>p</i> = 0.001), anterior periventricular (beta = –0.4 per SD, <i>p</i> = 0.001), parietal (beta = –0.2 per SD, <i>p</i> = 0.02) and frontal (beta = –0.3 per SD, <i>p</i> = 0.002) WMHVs were associated with SPPB; other WMHV and SBI were not associated with the SPPB. <b><i>Conclusions:</i></b> WMHV, especially in the anterior ­cerebral regions, is associated with a lower SPPB. Prevention of subclinical cerebrovascular disease is a potential target to prevent physical decline in the elderly