Objective: To examine rest–activity circadian rhythm (RAR) and cognitive decline in older men. Design: Longitudinal. Setting: Osteoporotic Fractures in Men (MrOS) and ancillary Outcomes of Sleep Disorders in Men (MrOS Sleep) studies. Participants: MrOS and MrOS Sleep participants (N=2,754; mean age 76.0 ± 5.3). Measurements: The Modified Mini-Mental State examination (3MS) was used to assess cognition at baseline (2003–05) and follow-up examinations (2005–06 and 2007–09). Wrist actigraphy was used to measure 24-hour activity counts at baseline. RAR variables included amplitude (strength of activity rhythm), mesor (mean activity level), pseudo F-statistic (overall circadian rhythm robustness), and acrophase (time of daily peak activity). Results: After an average of 3.4 ± 0.5 years, men with lower amplitudes, mesors, and pseudo F-statistics had greater decline in 3MS performance (amplitude: –0.7 points Q1 vs –0.5 points Q4, p<.001; mesor: –0.5 points Q1 vs –0.2 points Q4, p=.01; pseudo F-statistic: –0.5 points Q1 vs –0.3 points Q4, p<.001). Lower amplitudes and pseudo-F statistics were associated with greater odds of clinically significant cognitive decline (≥5-point decrease) (amplitude Q1 vs. Q4: odds ratio (OR)=1.4, 95% confidence interval (CI)=1.0–1.9; pseudo-F statistic Q1 vs Q4: OR=1.4, 95% CI=1.0–1.9). Men with phase-advanced acrophase had greater odds of clinically significant cognitive decline (OR=1.8, 95% CI=1.2–2.8). Results were adjusted for multiple confounders. Conclusion: Several parameters of disrupted RAR (lower amplitude, pseudo F-statistic, mesor, phase-advanced acrophase) were associated with greater cognitive decline in older community-dwelling men. These findings contribute to a growing body of evidence suggesting that altered RARs are associated with cognitive decline in older adults. J Am Geriatr Soc 66:2136–2143, 2018.
Bibliographical noteFunding Information:
Financial Disclosure: The MrOS is supported by National Institutes of Health (NIH) funding. The following institutes provide support: National Institute on Aging (NIA), National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Center for Advancing Translational Sciences (NCATS), and NIH Roadmap for Medical Research under Grants U01 AG027810, U01 AG042124, U01 AG042139, U01 AG042140, U01 AG042143, U01 AG042145, U01 AG042168, U01 AR066160, and UL1 TR000128. The National Heart, Lung, and Blood Institute (NHLBI) provides funding for the MrOS Sleep ancillary study "Outcomes of Sleep Disorders in Older Men" under the following grant numbers: R01 HL071194, R01 HL070848, R01 HL070847, R01 HL070842, R01 HL070841, R01 HL070837, R01 HL070838, R01 HL070839 and R21 AG051380.
- cognitive decline
- rest-activity rhythm