Fish oil, vitamin D supplementation during pregnancy may reduce croup risk in children

Supplementation with fish oil and high-dose vitamin D during pregnancy reduced the risk for croup in early childhood, researchers reported at the European Respiratory Society International Congress.

“There is currently no vaccine against the pathogen that causes [croup]. Therefore, other preventive strategies are needed, and measures initiated during pregnancy might be important since croup occurs in babies and young children,” Nicklas Brustad, MD, PhD, clinician and postdoctoral researcher from the Copenhagen Prospective Studies on Asthma in Childhood at Herlev and Gentofte Hospital at the University of Copenhagen, Denmark, said in a related press release. “For such purpose, there is evidence that both vitamin D and fish oil could have an influence on the immune system.”

The factorial, double-blind, randomized controlled trial evaluated the supplementation impact of fish oil containing omega-3 long-chain polyunsaturated fatty acids compared with olive oil, and high-dose vitamin D 2,800 IU per day compared with a standard dose of 400 IU per day in pregnant women from week 24 until 1 week after birth on the risk for croup in offspring until age 3 years.

Researchers investigated 736 pregnant women from the Danish population-based single-center Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort. Participants were randomly assigned a high-dose vitamin D supplement and fish oil 2.4 g, high-dose vitamin D and olive oil, standard-dose vitamin D and fish oil or standard-dose vitamin D and olive oil.

Croup diagnosis in offspring was diagnosed by physicians during clinical examinations and medical record checks.

Fourteen percent of the 695 children born during the study period had croup before age 3 years.

Children of mothers who received fish oil had a 38% reduced risk for croup compared with those who received olive oil (11% vs. 17%; HR = 0.62; 95% CI, 0.41-0.93; P = .02). In addition, children of mothers who received high-dose vitamin D had a 40% reduced risk for croup compared with those who received standard-dose vitamin D (11% vs. 18%; HR = 0.6; 95% CI, 0.38-0.93; P = .02).

These results remained after the researchers adjusted for each supplement, persistent wheeze and lower respiratory tract infection.

“Our findings suggest that vitamin D and fish oil could be beneficial against childhood croup in sufficiently high doses. These are relatively cheap supplements, meaning that this could be a very cost-effective approach to improving young children’s health,” Brustad said. “We are not sure of the exact mechanisms behind the beneficial effects of vitamin D and fish oil, but it could be that they can stimulate the immune system to help babies and young children clear infections more effectively.”

Reference:

• Fish oil and vitamin D supplements in pregnancy lower the risk of croup in babies and young children. Published Sept. 4, 2022. Accessed Sept. 7, 2022.