title: Low 25-hydroxyvitamin D concentrations predict incident depression in well-functioning older adults: the health, aging, and body composition study.
abstract: BACKGROUND
  Cross-sectional studies suggest that low 25-hydroxyvitamin D (25[OH]D) may be a risk factor for depression; however, there are few prospective studies. We examined the association between 25(OH)D and depressive symptoms in community-dwelling persons aged 70-79 years in the Health, Aging, and Body Composition (Health ABC) Study (n = 2598).
  
  
  METHODS
  Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression Scale (CES-D) at baseline and 2-, 3- and 4-year follow-up. Serum 25(OH)D was measured at 1-year follow-up and categorized as <20, 20-<30, and ≥30 ng/mL. Mixed models were used to examine change in CES-D scores according to 25(OH)D categories. The association between 25(OH)D categories and incident depression (CES-D short score ≥10 or antidepressant medication use) were assessed using Cox proportional hazards models. Analyses were adjusted for socio-demographic and behavioral characteristics, season, and chronic conditions.
  
  
  RESULTS
  Thirty-three percent of participants had 25(OH)D <20ng/mL. Serum 25(OH)D was not associated with CES-D scores at baseline (p = .51); however, CES-D scores increased over time and were significantly associated with 25(OH)D at 2-year (p = .003) and 4-year follow-up (p < .001). Among 2,156 participants free of depression at the 1-year follow-up, the cumulative incidence of depression was 26.9%. Participants with 25(OH)D <20ng/mL were at greater risk of developing depression (HR [95% CI]: 1.65 [1.23-2.22]) over 4 years of follow-up compared with those with 25(OH)D ≥30ng/mL.
  
  
  CONCLUSIONS
  Low 25(OH)D was independently associated with a greater increase in depressive symptom scores and incident depression in community-dwelling older adults.
authors.affiliation: Department of Internal Medicine-Gerontology and Geriatric Medicine and juwillia@wakehealth.edu.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Williams
authors.affiliation: Department of Internal Medicine-Gerontology and Geriatric Medicine and.
authors.forename: Kaycee M
authors.initials: KM
authors.lastname: Sink
authors.affiliation: Department of Internal Medicine-Gerontology and Geriatric Medicine and.
authors.forename: Janet A
authors.initials: JA
authors.lastname: Tooze
authors.affiliation: Department of Internal Medicine-Gerontology and Geriatric Medicine and.
authors.forename: Hal H
authors.initials: HH
authors.lastname: Atkinson
authors.affiliation: Department of Epidemiology, University of Pittsburgh, Pennsylvania.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.affiliation: Department of Psychiatry, University of California, San Francisco.
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.affiliation: Department of Biostatistics and Epidemiology, University of Tennessee Health Sciences, Memphis.
authors.forename: Frances A
authors.initials: FA
authors.lastname: Tylavsky
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Rubin
authors.affiliation: National Institute of Aging, Baltimore, Maryland.
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.affiliation: Department of Internal Medicine-Gerontology and Geriatric Medicine and.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.affiliation: Department of Internal Medicine-Gerontology and Geriatric Medicine and.
authors.forename: Denise K
authors.initials: DK
authors.lastname: Houston
mesh_terms: D000368:Aged; D000375:Aging; D000928:Antidepressive Agents / Q000627:therapeutic use; D044383:Black People; D003863:Depression / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D010414:Pennsylvania / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D013714:Tennessee / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D044465:White People; D001741:Black or African American
chemical_list: D000928:Antidepressive Agents; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Depression; Epidemiology; Nutrition.; Risk factors