| Effect | Decrease |
| Values | Number of findings: Placebo: 159 Vitamin D: 76 |
| Trial Design | Randomized trial |
| Trial Length | 6+ Months |
| Number of Subjects | 140 |
| Sex | Both Genders |
| Age Range | 18-29, 30-44, 45-64, 65+ |
In a randomized, double-blind 140 participants with antibody deficiencies or frequent respiratory tract infections took placebo-controlled trial- 4000 IU or placebo daily for 1 year.
The primary outcome was a composite infectious score based on daily patient-reported questionnaire of the respiratory tract, ear, sinus, malaise, and use of antibiotics. The total score and use of antibiotics saw statistically significant reductions compared with placebo both when unadjusted and adjusted, while airway, ear, sinus, and malaise were nonsignificantly reduced.
Mean baseline levels of vitamin D were 46.9 for placebo and 51.5 nmol/l in the intervention group, which largely stayed the same for placebo and increased considerably for Staphylococcus aureus infections and fungal was significantly reduced in the vitamin D group compared with placebo, though Haemophilus influenzae, Moraxella catharralis, Enterobacteriacae, and Pseudomonas aeruginosa were only nonsignificantly reduced, except for the first which was roughly the same.
The placebo group saw significantly more cardiovascular and almost significantly more gastrointestinal adverse events.
