Vitamin D status is not associated with the risk of hospitalization for acute bronchiolitis in early childhood

The association between vitamin D status and susceptibility to acute lower respiratory tract infection (ALRI) was studied in young Canadian children. Serum 25-hydroxyvitamin D (25(OH) D) concentrations were measured in patients aged 1-25 months admitted to hospital with uncomplicated ALRI (primarily viral bronchiolitis) as well as in healthy, similarly aged patients without a history of hospitalization for ALRI (controls). Serum 25(OH) D concentrations were similar among cases and controls (77.0 versus 77.2 nmol l(-1); P=0.960), and there was no case-control difference in the prevalence of vitamin D insufficiency using two thresholds (< 40 nmol l(-1): 4.7 versus 1.5%, P=0.365; < 80 nmol l(-1): 51.6 versus 56.9%, P=0.598). Vitamin D status was not associated with the risk of hospitalization for ALRI in this population.