Relationship between low serum vitamin D status and urinary tract infection in children: a case-control study.

Background A link between vitamin D deficiency and susceptibility to bacterial and viral infections has recently been suggested. Aim To investigate a possible association between vitamin D deficiency and urinary tract infection (UTI). Methods A case-control study was undertaken comprising 75 children aged 2-7 years with UTI (cases) compared with 75 healthy controls in terms of serum 25 hydroxyvitamin D [25(OH)D] levels. Serum 25(OH)D levels were measured using a chemiluminescence assay. For cases, dimercaptosuccinic acid (DMSA) renal scan was used as the gold standard to distinguish between acute lower UTI (cystitis) and acute pyelonephritis. Results Median (IQR) 25(OH)D levels were lower in the UTI group [14.5 ng/mL (9.4-18.8)] than in the controls [27 ng/mL (22.4-39.0)] (p< 0.001). In addition, the prevalence of 25(OH)D levels <20 ng/mL was higher in the children with UTI than in the controls (68%vs18%) (p< 0.001). There was a statistically significant difference between the cystitis and pyelonephritis groups in mean (SD) serum 25(OH)D levels-18.76 (9.35) ng/mLvs13.94 (6.97) ng/mL,p< 0.05, respectively. Conclusion Low serum vitamin D is associated with UTI and supports the hypothesis that children with low vitamin D levels could be at greater risk of UTI.