Quantitative gait markers and incident fall risk in older adults.

BACKGROUND: Identifying quantitative gait markers of falls in older adults may improve diagnostic assessments and suggest novel intervention targets.
METHODS: We studied 597 adults aged 70 and older (mean age 80.5 years, 62% women) enrolled in an aging study who received quantitative gait assessments at baseline. Association of speed and six other gait markers (cadence, stride length, swing, double support, stride length variability, and swing time variability) with incident fall rate was studied using generalized estimation equation procedures adjusted for age, sex, education, falls, chronic illnesses, medications, cognition, disability as well as traditional clinical tests of gait and balance.
RESULTS: Over a mean follow-up period of 20 months, 226 (38%) of the 597 participants fell. Mean fall rate was 0.44 per person-year. Slower gait speed (risk ratio [RR] per 10 cm/s decrease 1.069, 95% confidence interval [CI] 1.001-1.142) was associated with higher risk of falls in the fully adjusted models. Among six other markers, worse performance on swing (RR 1.406, 95% CI 1.027-1.926), double-support phase (RR 1.165, 95% CI 1.026-1.321), swing time variability (RR 1.007, 95% CI 1.004-1.010), and stride length variability (RR 1.076, 95% CI 1.030-1.111) predicted fall risk. The associations remained significant even after accounting for cognitive impairment and disability.
CONCLUSIONS: Quantitative gait markers are independent predictors of falls in older adults. Gait speed and other markers, especially variability, should be further studied to improve current fall risk assessments and to develop new interventions.