Vitamin D deficiency was infrequent among infants hospitalized with respiratory syncytial virus bronchiolitis, and when present, occurred among young infants and infants who breast-fed, according to study findings in The Journal of the Pediatric Infectious Diseases Society.

Researchers assessed 145 infants, with a mean age of 4.3 months, who were enrolled in the RSV Bronchiolitis in Early Life II (RBEL II) cohort from 2009 to 2012. All infants tested positive for RSV and had physician-documented wheezing. Researchers evaluated the relationship between vitamin D status at enrollment and the duration of hospitalization, lowest oxygen saturation measured during hospitalization, and bronchiolitis severity score.

Regarding baseline vitamin D levels, median serum level was 36.8 ng/mL. Fourteen infants (9.7%) had vitamin D levels below 20 ng/mL, indicating vitamin D deficiency. Twenty-three infants (15.8%) had serum levels between 20 and 29.9 ng/mL.