Vitamin D May Lower Suicide Risk in Veterans by Nearly 50%

Vitamin D supplementation cuts the risk of suicide attempts or self harm in veterans by nearly fifty percent, and almost seventy percent in Black veterans, a new PLoS One study suggested.

In the US, low levels of vitamin D are common, particularly in the military, where over 30 percent of members are considered vitamin D deficient, the researchers wrote. Although some clinical trials have not shown any benefit to supplementation – or even demonstrated harm in some cases – a growing body of evidence has has drawn a direct line between suicidal behavior and levels of serum 25-hydroxyvitamin D below 20 ng/mL.  Adjuvant treatment with vitamin D supplementation might help reduce suicidal urges by reaching the receptors in parts of the brain associated with depression. 

In this retrospective cohort study, researchers reviewed the electronic medical records of 495 service members who were taking a Vitamin D2 or D3 prescription over an eight year period and compared them to a group of veterans who didn’t take the supplements. They wanted to see if taking either form of the vitamin had any protective effect against suicide attempts or self-harm after accounting for a number of other factors including race, gender, dosage, and blood levels.

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Supplementation with either form of the vitamin was associated with a reduction in suicide ideation in men and women, with vitamin D2 related to a 48.8 percent reduction in attempts and vitamin D3 related to a 44.8 percent reduction in attempts. Black veterans and vets with low vitamin D levels saw even better results – up to a 64 percent greater risk reduction for suicidal behavior compared to those who didn’t take supplements.

Only vitamin D3, called cholecalciferol, demonstrated a dose-response effect in D-deficient veterans, with more significant reductions in suicide attempt and self-harm risk at higher doses, the data showed. This finding is consistent with the pharmacology of the two D vitamins, the researchers wrote. When supplements are composed of plant-based ingredients, as with D2 (ergocalciferol) rather than from animal-based ingredients as with cholecalciferol, the inactive vitamin D storage form has a shorter half-life. Thus, cholecalciferol was shown to increase blood serum levels more efficiently than ergocalciferol, they wrote.

The study did have a few limitations worth considering. Some vets in the control group might have been supplementing with over-the- counter options, which are relatively accessible and inexpensive, and this may have confounded the results. Vets in the supplementation group might also have practiced other behaviors not captured in the data that helped them maintain a more positive mental outlook. And, things like traumatic brain injuries that are common in the military community and have an influence on suicidality, went unaccounted for in the study.

“Our findings should therefore be interpreted as associations rather than causal effects,” study authors Jill E. Lavigne, and Jason B. Gibbons wrote. “Concerning generalizability, the VA is primarily male and middle-aged, so our associations may not be generalizable to other populations.”

Any promising suicide prevention strategy is worth considering for the military population. As a recent The Primary Care Companion for CNS Disorders investigation noted, veteran suicides continue to be a national health crisis. In 2014, a mean of 20 veterans died of suicide each day, making their risk for suicide 21 percent higher than average. During that same year, veterans accounted for 18 percent of all deaths from suicide among US adults, despite making up just 8.5 percent of the total population.

“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,” the PLoS One researchers wrote.