Is Vitamin D the Missing Link in Recurrent Urinary Tract Infections in Children? A Prospective Study

Purpose Vitamin D's key role in immunity may help prevent urinary tract infections (UTIs). This study aimed to explore the impact of vitamin D supplementation on preventing recurrent UTIs in children. Methods This prospective case-control study included 18 school-aged children with recurrent UTIs and 19 healthy children. Serum vitamin D levels were compared between the groups. Vitamin D supplementation was administered to children with recurrent UTIs. Vitamin D concentrations before and after supplementation, and recurrence frequency during the study period, were evaluated. Results The mean serum vitamin D levels in the patient group were lower than those in the healthy control group (15.89 ± 6.76 vs. 19.96 ± 10.08 ng/mL), but this difference was not statistically significant (p = 0.16). However, vitamin D deficiency was significantly more prevalent in the patient group (88.9% vs 36.8%, p = 0.002). Vitamin D serum levels increased significantly after supplementation (15.89 ± 6.76 vs 19.96 ± 8.77 ng/mL, p = 0.04) and the proportion of patients with vitamin D deficiency decreased significantly (%88.9 vs %38.9, p = 0.004). The median number of UTI episodes decreased significantly (2.0 vs. 1.5 episodes, p = 0.014). Conclusion Vitamin D deficiency is more common in children with recurrent UTIs. Vitamin D supplementation significantly increased vitamin D levels and is associated with a lower recurrence rate of UTIs. Correcting vitamin D deficiency and maintaining adequate levels may be a simple and effective method for preventing recurrent UTIs in school-aged children. Trial registration number and date of registration: 2021/605, 09.09.2021