Association of Dual Decline in Memory and Gait Speed With Risk for Dementia Among Adults Older Than 60 Years
Publisher's version (útgefin grein) ; Importance: Dual decline in both memory and gait speed may characterize a group of older individuals at high risk for future dementia. Objective: To assess the risk of dementia in older persons who experience parallel declines in memory and gait speed compared with those who experience no decline or decline in either memory or gait speed only. Design, Setting, and Participants: A multicohort meta-analysis was performed of 6 prospective cohort studies conducted between 1997 and 2018 in the United States and Europe. Participants were 60 years or older, had an initial gait speed of more than 0.6 m/s (ie, free of overt dismobility), with repeated measures of memory and gait speed before dementia diagnosis during a mean follow-up of 6.6 to 14.5 years. Within each study, participants were divided into 4 groups: memory decline only, gait speed decline only, dual decline, or no decline (hereafter referred to as usual agers). Gait decline was defined as a loss of 0.05 m/s or more per year; memory decline was defined as being in the cohort-specific lowest tertile of annualized change. Main Outcomes and Measures: Risk of incident dementia according to group membership was examined by Cox proportional hazards regression with usual agers as the reference, adjusted for baseline age, sex, race/ethnicity, educational level, study site, and baseline gait speed and memory. Results: Across the 6 studies of 8699 participants, mean age ranged between 70 and 74 years and mean gait speed ranged between 1.05 and 1.26 m/s. Incident dementia ranged from 5 to 21 per 1000 person-years. Compared with usual agers, participants with only memory decline had 2.2 to 4.6 times higher risk for developing dementia (pooled hazard ratio, 3.45 [95% CI, 2.45-4.86]). Those with only gait decline had 2.1 to 3.6 times higher risk (pooled hazard ratio, 2.24 [95% CI, 1.62-3.09]). Those with dual decline had 5.2 to 11.7 times the risk (pooled hazard ratio, 6.28 [95% CI, 4.56-8.64]). Conclusions and Relevance: In this study, dual decline of memory and gait speed was associated with increased risk of developing dementia among older individuals, which might be a potentially valuable group for preventive or therapeutic interventions. Why dual decline is associated with an elevated risk of dementia and whether these individuals progress to dementia through specific mechanisms should be investigated by future studies. ; This research work was supported by the Intramural Research Program of the National Institutes of Health, National Institute on Aging (Drs Tian, Resnick, Launer, Simonsick, Studenski, and Ferrucci). The BLSA was supported by the Intramural Research Program of the National Institutes of Health, National Institute on Aging. The AGES-Reykjavik Study was funded by contract N01-AG-12100 from the National Institutes of Health; by the Intramural Research Program of the National Institute on Aging; and by the Icelandic Heart Association and the Icelandic Parliament. The Health ABC study was supported by National Institute on Aging contracts N01-AG-6-2101, N01-AG-6-2103, and N01-AG-6-2106; National Institute on Aging grant R01-AG028050; and National Institute of Nursing Research grant R01-NR012459, and was funded in part by the Intramural Research Program of the National Institutes of Health, National Institute on Aging. The MCSA was supported by funding from the National Institutes of Health, National Institute on Aging (U01 AG006786), the Gerald and Henrietta Rauenhorst Foundation, and the Mayo Foundation for Medical Education and Research; and was made possible by the Rochester Epidemiology Project (R01 AG034676). The SNAC-K was supported by the funders of the Swedish National Study on Aging and Care; the Ministry of Health and Social Affairs, Sweden; the participating County Councils and Municipalities; and the Swedish Research Council. The InCHIANTI study was supported by National Institute on Aging contracts 263MD9164 (Dr Ferrucci) and 263 MD 821336, N01-AG-1-1, N01-AG-10211, and N01-AG-5-0002 (Dr Bandinelli), and partially supported by grant n PE 2011 02350413 of the Italian Ministry of Health (Dr Cherubini). ; Peer Reviewed