Enhancing fall risk assessment in the oldest old: The interplay of cognition and gait speed.

Individuals 90 + years have a high prevalence of falls, often with devastating consequences. Fall risk assessment and early intervention can prevent falls, yet factors associated with fall risk are understudied in this high-risk group. We aimed to evaluate whether slow gait, impaired cognition, or a combination of the two are associated with elevated fall risk in the oldest old. Participants were from The 90 + Study, a longitudinal study with evaluations every six months. We tested the association of 'slow gait' (Four-Meter Walk Test, below sex-specific median), 'impaired cognition' (cognitive impairment no dementia or dementia), and 'both' (slow gait and impaired cognition) with fall rate over time. We used generalized linear mixed regression models to estimate incidence rate ratios (IRRs) using 'none' (neither slow gait nor impaired cognition) as the reference. We analyzed 1099 participants (749 women, 350 men, mean age 93.2 years). Prevalence of slow gait, impaired cognition, and falls was similar in men and women. In women, 'slow gait' (IRR = 1.33, 95% CI = 1.03-1.72) and 'both' (IRR = 1.35, 95% CI = 1.06-1.73) were significantly associated with an elevated risk of future falls, whereas 'impaired cognition' was not (IRR = 1.06, 95% CI = 0.83-1.36). In contrast, in men, 'slow gait' (IRR = 1.70, 95% CI = 1.15-2.50), 'impaired cognition' (IRR = 1.75, 95% CI = 1.21-2.53), and 'both' (IRR = 2.34, 95% CI = 1.66-3.30) were all significantly associated with an elevated risk of future falls. Gait and cognition both play an important role in fall risk assessment in the oldest and fastest-growing segment of the U.S. population.