Vitamin D deficiency is associated with urinary tract infection in children.

Introduction: In humans, vitamin D has been shown to play a role in infectious diseases, but its association with acquisition and a complicated course of febrile urinary tract infections (UTIs) has not been investigated. We aimed to investigate the association between 25-hydroxyvitamin D (25(OH)D3 ) levels and the risk of first time febrile UTI in children.

Material and methods: This prospective case-control study included 50 children with first febrile UTI, with no risk factors for UTI, and 50 age- and sex-matched healthy siblings as controls. White blood cell count, serum C-reactive protein, calcium, phosphorus, alkaline phosphatase and parathormone were measured in all studied children. Vitamin D status was determined by measuring plasma 25(OH)D3 level. Deficiency was defined as a plasma 25(OH)D3 level ≤ 25 nmol/l.

Results: Children with UTI had significantly lower mean serum levels of 25(OH)D3 (10.5 ±2.7 nmol/l) than those of controls (25.9 ±5.6 nmol/l) ( p < 0.05). Patients with lower UTI had significantly higher serum levels of 25(OH)D3 compared to those with acute pyelonephritis (12.4 ±2.59 vs. 8.2 ±3.2 nmol/l; p < 0.001). Mean serum levels of 25(OH)D3 were significantly lower ( p = 0.001) in the female patients compared with males, and this difference was not found within the control group. Multivariate analysis showed that a serum 25(OH)D3 level of ≤ 25 nmol/l is associated with UTI (OR = 1.94, 95% CI: 1.61-2.82; p = 0.04).

Conclusions: Vitamin D deficiency (≤ 25 nmol/l) was an independent risk factor for UTI in children.