Infants who are born with deficient levels of vitamin D appear to have an increased risk of developing a severe lower respiratory tract infection, a new study has found. The findings, by researchers from the Netherlands, appear today in Pediatrics.
Previous studies have suggested that vitamin D might have a protective effect against illness caused by respiratory syncytial virus (RSV), the most common cause of severe lower respiratory tract infections in infants. While more than 90% of infants become infected with RSV before age 2 years, only 10% develop a severe lower respiratory tract infection, such as bronchiolitis (inflammation of the small airways in the lung) or pneumonia. Every year, up to 125 000 US children are hospitalized due to an RSV infection, according to the US Centers for Disease Control and Prevention.
In the Pediatrics study, the researchers determined vitamin D concentrations in the cord blood of 156 newborns, 18 of whom went on to develop an RSV lower respiratory tract infection during their first year of life. These 18 infants had lower concentrations of vitamin D at birth than the infants who did not develop an RSV lower respiratory tract infection. The 23% of infants born with the lowest vitamin D concentrations had a 6-fold increased risk of such an infection compared with the 46% of infants born with the highest vitamin D concentrations.
Offering vitamin D supplementation to pregnant women might decrease the risk of RSV-associated diseases in their children, the researchers said, noting that only 46% of the mothers in their study said that they were taking a vitamin D supplement during pregnancy. The American Association for Pediatrics and the World Health Organization recommend daily supplementation of 400 IU of vitamin D to all women who are pregnancy or breastfeeding, but the researchers noted that the optimal dose is still under debate and speculated that substantially higher doses might be needed for the optimal health of both mothers and infants.