title: Sleep variability, health-related practices, and inflammatory markers in a community dwelling sample of older adults.
abstract: OBJECTIVE
  To explore relationships between wake- and sleep-related health behaviors and circulating concentrations of inflammatory markers (interleukin [IL]-6 and tumor necrosis factor [TNF]-α) in a cohort of community dwelling older adults. Low-grade chronic inflammation is an important risk factor for age-related morbidity. Health behaviors, including average aggregate measures of sleep, have been linked to increased inflammation in older adults. Variability in sleep timing may also be associated with increased inflammation.
  
  
  METHODS
  Participants were community dwelling older adults ≥ 60 years (n = 222: 39 bereaved, 55 caregivers, 52 with insomnia, and 76 good sleepers). Mean values and intraindividual variability in sleep, as well as caffeine and alcohol use, exercise, and daytime napping, were assessed by sleep diaries. Blood samples were obtained in the morning.
  
  
  RESULTS
  Several interactions were noted between sleep behaviors, inflammatory markers, and participant group. Greater variability in wake time and time in bed was associated with higher IL-6 among good sleepers relative to caregivers and older adults with insomnia. Good sleepers who consumed moderate amounts of alcohol had the lowest concentrations of IL-6 compared with the other three groups who consumed alcohol. Insomnia subjects, but not good sleepers, showed increased concentrations of IL-6 associated with caffeine use. Caregivers showed increased concentrations of TNF-α with alcohol use relative to good sleepers. Greater variability in bedtime, later wake times, and longer time in bed was associated with higher TNF-α regardless of group.
  
  
  CONCLUSIONS
  Moderation and regularity in the practice of certain health behaviors, including sleep practices, were associated with lower plasma levels of inflammatory markers in older adults. Life circumstances and specific sleep disorders may modify these associations.
authors.affiliation: Sleep Medicine Institute and Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, Pittsburgh, PA 15213, USA. okunml@upmc.edu
authors.forename: Michele L
authors.initials: ML
authors.lastname: Okun
authors.forename: Charles F
authors.initials: CF
authors.lastname: Reynolds
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Buysse
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Monk
authors.forename: Sati
authors.initials: S
authors.lastname: Mazumdar
authors.forename: Amy
authors.initials: A
authors.lastname: Begley
authors.forename: Martica
authors.initials: M
authors.lastname: Hall
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking; D001601:Bereavement; D015415:Biomarkers / Q000097:blood*; D017028:Caregivers; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D015577:Geriatric Assessment; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D007249:Inflammation / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000097:blood; D012893:Sleep Wake Disorders / Q000097:blood; D011795:Surveys and Questionnaires; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha