Poor Physical Performance and Dementia in the Oldest Old The 90+ Study

Objective: To examine the cross-sectional relationship between physical performance and dementia in the oldest old (those >= 90 years of age). Design: Cross-sectional study. Setting: The 90+ Study is a population-based, longitudinal, epidemiologic study of aging and dementia performed at the University of California, Irvine, from January 1, 2003, through November 30, 2009. Participants: A total of 629 participants from The 90+ Study were included in the study. The mean age was 94 years, and most (72.5%) were women. Main Outcome Measures: All-cause dementia, based on Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria, was the main outcome measure. The independent variables were physical performance measures, including 4-m walk, 5 chair stands, standing balance, and grip strength, each scored from 0 to 4 (0, unable to perform; 4, best performance). Odds of dementia in relation to the physical performance measures were estimated by logistic regression after adjustment for age and sex. Results: Poor physical performance in all measures was significantly associated with increased odds of dementia (P < .001). Odds ratios for every unit decrease in physical performance score were 2.1 for 4-m walk, 2.1 for chair stands, 1.9 for standing balance, and 1.7 for grip strength. Conclusions: We found a strong cross-sectional relationship between poor physical performance and dementia in people 90 years and older. Our findings suggest that dementia is a complex neurodegenerative process that may affect physical performance and cognition. Additional research is necessary to determine the temporal relationship between poor physical performance and cognitive dysfunction. JAMA Neurol. 2013;70(1):107-113. Published online October 22, 2012. doi:10.1001/jamaneurol.2013.583