Vitamin D Correlation with Testosterone Concentration in US Army Special Operations Personnel

Laurel Wentz,Cristóbal Berry-Cabán,Jerad Eldred,Qiang Wu

Abstract

Vitamin D has been positively correlated with testosterone in older men, but these hormonal relationships have not been examined in younger, active military personnel. Therefore, the purpose of this study was to identify significant correlations between vitamin D and testosterone concentrations in male Special Operations Soldiers. This retrospective analysis examined unique cases of serum vitamin D assessments ordered at Womack Army Medical Center, Fort Bragg, NC, from January 2012 – September 2013. Inclusion criteria were male Special Operations soldiers who had a total testosterone assessment within 21 days of vitamin D assessment, yielding 312 service member records. Mean serum vitamin D concentrations were 29.9±9.6 ng/ml (range 10-63), with 52% of subjects in the deficient range of <30 ng/ml according to the Army Medical Department guidelines. In vitamin D deficient subjects, serum vitamin D concentrations were a significant positive predictor of total testosterone when controlling for age and body mass index.

Independent Variable	Testosterone in Vitamin D Deficient Men (n=135)
	Β	Ρ
Vitamin D	8.429	0.008
Age	-2.604	0.183
Body Mass Index	-1.569	0.678
Model R2	0.062

These data indicate that deficient vitamin D concentrations may inhibit testosterone production and potentially limit human performance. Operational stress of military training has been shown to suppress testosterone concentrations in healthy men, causing muscle catabolism and fatigue, symptoms also characteristic of vitamin D deficiency. Given that more than half of male soldiers had insufficient vitamin D status in a southern latitude, measuring vitamin D concentrations in collaboration with testosterone assessments may be warranted.