title: Low vitamin D status and suicide: a case-control study of active duty military service members.
abstract: OBJECTIVE
  Considering that epidemiological studies show that suicide rates in many countries are highest in the spring when vitamin D status is lowest, and that low vitamin D status can affect brain function, we sought to evaluate if a low level of 25-hydroxyvitamin D [25(OH)D] could be a predisposing factor for suicide.
  
  
  METHODS
  We conducted a prospective, nested, case-control study using serum samples stored in the Department of Defense Serum Repository. Participants were previously deployed active duty US military personnel (2002-2008) who had a recent archived serum sample available for analysis. Vitamin D status was estimated by measuring 25(OH) D levels in serum samples drawn within 24 months of the suicide. Each verified suicide case (n = 495) was matched to a control (n = 495) by rank, age and sex. We calculated odds ratio of suicide associated with categorical levels (octiles) of 25(OH) D, adjusted by season of serum collection.
  
  
  RESULTS
  More than 30% of all subjects had 25(OH)D values below 20 ng/mL. Although mean serum 25(OH)D concentrations did not differ between suicide cases and controls, risk estimates indicated that subjects in the lowest octile of season-adjusted 25(OH)D (<15.5 ng/mL) had the highest risk of suicide, with subjects in the subsequent higher octiles showing approximately the same level of decreased risk (combined odds ratio compared to lowest octile = 0.49; 95% C.I.: 0.315-0.768).
  
  
  CONCLUSIONS
  Low vitamin D status is common in active duty service members. The lowest 25(OH)D levels are associated with an increased risk for suicide. Future studies could determine if additional sunlight exposure and vitamin D supplementation might reduce suicide by increasing 25(OH) D levels.
authors: National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA. umhau@jhu.edu
authors: John C
authors: JC
authors: Umhau
authors: David T
authors: DT
authors: George
authors: Robert P
authors: RP
authors: Heaney
authors: Michael D
authors: MD
authors: Lewis
authors: Robert J
authors: RJ
authors: Ursano
authors: Markus
authors: M
authors: Heilig
authors: Joseph R
authors: JR
authors: Hibbeln
authors: Melanie L
authors: ML
authors: Schwandt
mesh_terms: D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008889:Military Personnel; D016017:Odds Ratio; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D013405:Suicide; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014815:Vitamins / Q000097:blood*
chemical_list: D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D