Physical activity and risk of cognitive impairment among oldest-old women.

OBJECTIVES: Physical activity may reduce the risk of cognitive decline in the elderly, but its effects among the oldest-old (i.e., those aged 85 years and older) are not well known. Our study assessed the association between very late-life physical activity and 5-year risk of mild cognitive impairment (MCI) or dementia and neuropsychological test performance among oldest-old women.
METHODS: This prospective study was conducted at three sites. Participants included 1,249 women (mean [standard deviation] age: 83.3 [2.8] years). Baseline physical activity was measured by self-reported blocks walked per week and analyzed according to tertile. Five years later, surviving participants who were 85 years and older (oldest-old) completed neuropsychological testing and underwent adjudication of clinical cognitive status (normal, MCI, or dementia). All analyses were adjusted for baseline age, education, cognition, depression, body mass index, hypertension, smoking, and coronary artery disease.
RESULTS: Compared with women in the lowest tertile, women in the highest tertile were less likely to develop dementia (13.0% versus 23.2%; multivariate adjusted odds ratio: 0.54 [95% confidence interval: 0.36-0.82]). However, risk of MCI was not associated with physical activity. Physical activity was also associated with higher performance 5 years later on tests of global cognition, category fluency, and executive function but not phonemic fluency, memory, or attention.
CONCLUSIONS: Higher level of very late-life physical activity was associated with a lower risk of subsequent dementia in oldest-old women. These findings support future studies for late-life physical activity interventions for the prevention of dementia among oldest-old women.