May 9th, 2011
12:01 AM ET
Infants who are deficient in vitamin D at birth are at six times higher risk for getting RSV, or respiratory syncytial virus during their first year of life compared with infants with very high levels of vitamin D, says a new study in the journal Pediatrics.
"Vitamin D intake during pregnancy most likely prevents a highly frequent, severe disease during infancy," said Dr. Louis Bont, a pediatric infectious disease specialist at Wilhelmina Children's Hospital in Utrecht, Netherlands.
Most times, RSV results in cold-like symptoms for both adults and babies. The Centers for Disease Control and Prevention says almost all children get the virus by the time they reach age 2, but only some develop severe disease.
Approximately 75,000 to 125,000 children under the age of 1 are hospitalized each year in the United States because of infection from RSV. Some get bronchiolitis, while others develop pneumonia. Bronchiolitis involves inflammation of the small airways in the lung. Pneumonia also is inflammation in the lungs.
Bont said it could also affect a child's quality of life.
"Once the children are discharged, half of them go on to still have asthma-like symptoms," he said.
The study looked at 156 newborns in the Netherlands. They found a strong association between cord blood vitamin D levels and women taking vitamin D3 supplements during their pregnancy. About half of newborns had low vitamin D levels, and 18 developed RSV lower respiratory tract infections during their first year.
Only 46% of women taking part in the study said they used vitamin D supplements during their pregnancy.
"I assume that American pregnant women are not that different from the Dutch- not everybody adheres to all guidelines existing," Bont said. "We show that [vitamin D intake] is relevant for a severe and frequent respiratory tract infection during infancy and I think this is a very good reminder that people should take what has been advocated."
The Institute of Medicine says that pregnant women need at least 400 international units of vitamin D per day, but the recommended daily allowance is 600 IUs each day.
"RSV is just one of the infections of early childhood that may be impacted by in-utero vitamin D," said Dr. Jennifer Shu, a practicing pediatrician and CNNHealth's Living Well expert. "Because RSV can be serious and difficult to treat, being able to prevent severe infections with vitamin D may decrease RSV rates and complications (and may help with other immune functions) in the future."
Shu said someday pregnant women may be advised to get more vitamin D, but that the ideal amount is not yet known.
"Prenatal vitamins do contain vitamin D, but research may prove that the amount needs to be increased," she said.
Bont agrees that it is too early to up the recommended dose.
"We don't know whether it's more effective and we don't know whether unexpected side effects could occur," he said. "We have to wait for trials."
The study took into consideration the seasons in which the women were pregnant. Researchers also studied giving the babies vitamin D supplements after birth. Neither had any impact on the findings.
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