Low vitamin D status and suicide: a case-control study of active duty military service members

• Published in: PloS one Vol. 8; no. 1; p. e51543
• Main Authors: Umhau, John C, George, David T, Heaney, Robert P, Lewis, Michael D, Ursano, Robert J, Heilig, Markus, Hibbeln, Joseph R, Schwandt, Melanie L
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04-01-2013; Public Library of Science (PLoS)
• Subjects: 25-Hydroxyvitamin D; Active control; Adult; Age Factors; Alcoholism; Analysis; Armed forces; Astronomical Sciences; Biology; Brain; Brain research; Case-Control Studies; Epidemiology; Female; Health sciences; Humans; Low level; Male; Medicine; Mental depression; Mental health; Military; Military deployment; Military Personnel; Military psychology; Neurosciences; Odds Ratio; Population; Preventive medicine; Principal components analysis; Psychiatry; Risk Factors; Risk management; Seasons; Sex Factors; Sex ratio; Social and Behavioral Sciences; Suicide; Suicides & suicide attempts; Supplements; Surveillance; Vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin deficiency; Vitamins - blood; United States > US; Maryland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0051543

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.
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.
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).
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.