The retrospective cohort study also showed that higher daily vitamin D supplement dosages appeared to offer greater protection against suicide and self-harm risk than lower doses, that the effect was greater among those with baseline vitamin D deficiency or insufficiency, and that both vitamin D2 (ergocalciferol) and D3 (cholecalciferol) supplements were effective.
“As a relatively safe, easily accessible, and affordable medication, supplementation with vitamin D in the [Veterans Administration] may hold promise if confirmed in clinical trials to prevent suicide attempts and suicide,” write Jill E. Lavigne, PhD, and Jason B. Gibbons, PhD, in their study, published online February 1 in PLoS One.
Pending those confirmatory trials, they advise: “Providers may wish to initiate low-dose vitamin D supplementation, for example, at the US [recommended dietary allowance] level of 600 IU per day, without screening in patients with a history of suicidal behavior or ideation or who exhibit warning signs of suicidal behavior.”
The US Preventive Services Task Force advises against routine vitamin D screening, and in a review of 11 trials found no differences in mortality with vitamin D supplementation, nor in incident depression in different populations.
However, “the subjects in those studies had adequate levels of vitamin D, so they didn’t have insufficiency. That was a big limitation and why there’s been this call for further research. Our paper uses real-world data,” Lavigne of the VA Center of Excellence for Suicide Prevention, Canandaigua, New York, told Medscape Medical News.
A Third of Military Members Are Vitamin D Deficient
Approximately a third of US military members have been shown to have 25-hydroxyvitamin D [25(OH)D] levels below 20 ng/mL, considered deficient.
Vitamin D deficiency is particularly common among males and among darker-skinned people. At the same time, servicemembers and veterans also have elevated suicide attempts and suicide rates, Lavigne and Gibbons note in their article.
Gibbons, a postdoctoral student in the Department of Health Policy & Management, Johns Hopkins University, Baltimore, Maryland, told Medscape Medical News: “There has been at least some indication around vitamin D as a potential supplement for depression and that those who are more severely depressed had greater benefits. So, it’s possible that some of what we’re seeing with these large effects is somewhat conditional on this being a more severely depressed population at baseline.”
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