SleepMay 8, 2021

Using daily activity patterns to predict new cases of dementia and mild memory problems in older women

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Apr 4, 2026

Abstract

Women with earlier sleep/wake times had a 66% higher risk of developing dementia compared to those with average sleep/wake times.

Earlier sleep/wake times are linked to an increased risk of dementia but not mild cognitive impairment (MCI).
A smaller difference between day and night activity levels is associated with a higher risk of dementia.
No associations were found between intradaily variability, interdaily stability, or the most active 10-hour period and the risk of MCI or dementia.
The timing of sleep and the amplitude of day/night activity may serve as potential predictors for dementia.

Simplified

STUDY OBJECTIVES: Disrupted daily rhythms are associated with mild cognitive impairment (MCI) and dementia. The specific nature of how rhythms and cognition are related, however, is unknown. We hypothesized characteristics from a nonparametric estimate of circadian rest-activity rhythm patterns would be associated to the development of MCI or dementia.

METHODS: Wrist actigraphy from 1232 cognitively healthy, community-dwelling women (mean age 82.6 years) from the Study of Osteoporotic Fractures was used to estimate rest-activity patterns, including intradaily variability (IV), interdaily stability (IS), most active 10-hour period (M10), least active 5-hour period (L5), and relative amplitude (RA). Logistic regression examined associations of these predictors with 5-year incidence of MCI or dementia. Models were adjusted for potential confounders.

RESULTS: Women with earlier sleep/wake times had higher risk of dementia, but not MCI, (early vs. average L5 midpoint: OR, 1.66; 95% CI, 1.08-2.55) as did women with smaller day/night activity differentials (low vs. high RA: OR, 1.96; 95% CI, 1.14-3.35). IV, IS, and M10 were not associated with MCI or dementia.

CONCLUSION: The timing and difference in day/night amplitude, but not variability of activity, may be useful as predictors of dementia.

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Using daily activity patterns to predict new cases of dementia and mild memory problems in older women

Abstract

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