title: Rest/activity rhythms and mortality rates in older men: MrOS Sleep Study.
abstract: An association between increased risk of mortality and disruptions in rest/activity circadian rhythms (RAR) has been shown among adults with dementia and with metastatic colorectal cancer. However, the association among a more general population of older adults has not been studied. Our study population consisted of 2964 men aged > or = 67 yrs of age enrolled in the Outcomes of Sleep Disorders in Older Men (MrOS Sleep) Study. Rest/activity patterns were measured with wrist actigraphy. RAR parameters were computed and expressed as quintiles, and included acrophase (time of peak activity level), amplitude (peak-to-nadir difference), mesor (middle of the peak), pseudo F-value (overall circadian rhythmicity), beta (steepness), and alpha (peak-to-trough width). After adjustment for multiple potential confounders, men in the lowest quintile of pseudo F-value had a 57% higher mortality rate (hazard ratio [HR] = 1.57, 95% CI, 1.03-2.39) than men in the highest quintile. This association was even stronger with increased risk of cardiovascular disease-related mortality (CVD) (HR = 2.32, 95% CI, 1.04-5.22). Additionally, men in the lowest quintile of acrophase had a 2.8-fold higher rate of CVD-related mortality (HR = 2.84, 95% CI, 1.29-6.24). There was no evidence of independent associations with amplitude, mesor, alpha, beta, and mortality risk. Older men with less robust RAR and earlier acrophase timing have modestly higher all-cause and CVD-related mortality rates. Further research should examine potential biological mechanisms underlying this association.
authors.affiliation: Division of Epidemiology & Community Health, University of Minnesota, Minneapolis, Minnesota, USA. ames0047@umn.edu
authors.forename: Misti L
authors.initials: ML
authors.lastname: Paudel
authors.forename: Brent C
authors.initials: BC
authors.lastname: Taylor
authors.forename: Sonia
authors.initials: S
authors.lastname: Ancoli-Israel
authors.forename: Terri
authors.initials: T
authors.lastname: Blackwell
authors.forename: Katie L
authors.initials: KL
authors.lastname: Stone
authors.forename: Greg
authors.initials: G
authors.lastname: Tranah
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
authors.forename: Steven R
authors.initials: SR
authors.lastname: Cummings
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Ensrud
mesh_terms: D056044:Actigraphy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D009026:Mortality; D009043:Motor Activity / Q000502:physiology*; D012146:Rest / Q000502:physiology*; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*