A double-blind, placebo-controlled study in Mongolian school children ( n = 120) examining the effect of vitamin D supplementation (800 IU/day) on tuberculin skin test conversion to positive showed a trend towards fewer conversions in the vitamin D group ( p = 0.06), suggesting a potential role of vitamin D in reducing the rate of acquisition of latent tuberculosis infection [ 210 ].
The prospective Intermountain Heart Collaborative Study with more than 40,000 participants revealed that 25(OH)D <15 ng/mL compared to 25(OH)D >30 ng/mL was associated with highly significant increases in the prevalence of type 2 diabetes mellitus, hypertension, hyperlipidemia, and peripheral vascular disease, coronary artery disease, myocardial infarction, heart failure, and stroke ( p < 0.0001), as well as with incident death (all-cause mortality was used as primary survival measure), heart failure, coronary artery disease/myocardial infarction ( p < 0.0001), stroke ( p = 0.003), and their composite ( p < 0.0001) [ 164 ].