Effects of Vitamin D Supplementation and Baseline Vitamin D Status on Acute Respiratory Infections and Cathelicidin: A Randomized Controlled Trial.

Background: Vitamin D supplementation may lower the risk of acute respiratory infection (ARI), and the effects may be mediated through the induction of cathelicidin production.

Objective: To study the effect of vitamin D supplementation on ARI and cathelicidin concentration in a randomized controlled trial (RCT) and to study the associations between baseline serum 25 hydroxyvitamin D (25(OH)D) and ARIs and cathelicidin concentrations in a 14-week follow-up study.

Methods: In the RCT study, the participants were randomized into 2 groups to receive either 20 µg of vitamin D or an identical placebo daily.

Associations of serum 25(OH)D levels with physical performance and anabolic hormones in young men.

The present study examined the association of vitamin D measured by serum 25(OH)D with physical performance outcomes and serum levels of anabolic hormones in young men. 412 young men (age 19 ± 1 year) entering their compulsory military service volunteered to participate in the study. The study consisted of two groups from two different military bases: Group A was studied in January and group B in July.