Expectant Moms Need Fresh Air

Air pollution exposure during pregnancy linked to lower vitamin D levels in newborns

(RxWiki News) If taking a breath of "fresh air" outside your door means inhaling exhaust, you might want to head to outlying parks more often during your pregnancy.

A recent study has found a link between city air pollution and lower levels of vitamin D in newborns. Low vitamin D levels have been linked to autoimmune conditions like asthma in some children.

"Get some fresh air often."

The study, led by Nour Baïz, MASc, of the National Institute of Health and Medical Research in Paris, France, aimed to find out whether urban air pollution could be one factor related to women's vitamin D levels.

The researchers studied 375 mothers and their children. They used a mathematical model called the Atmospheric Dispersion Modelling System to estimate the pollution at the mother's homes during pregnancy.

The model uses information on traffic conditions, the topography of the area, weather and background pollution.

The researchers used this to specifically estimate how much nitrogen dioxide the women were exposed to and how much air pollution made up of tiny particles the women were exposed to.

The tiny particles investigated were any pollution matter that was smaller that 10 micrometers in diameter.

This information was compared to the amount of vitamin D analyzed in the cord blood samples of the babies when they were born.

The researchers found that women who were exposed to high levels of nitrogen dioxide — levels commonly found in urban areas — were more likely to have babies with a vitamin D deficiency at birth.

The lower vitamin D levels also occurred in the newborns of women exposed to more of those tiny particles throughout their pregnancy.

For every increase of 10 micrograms per cubic meter of nitrogen oxide the women were exposed to, their newborns had 0.15 IU less vitamin D in their blood. IU is "international unit" and is one standard way to measure vitamins.

For every similar increase of the tiny particles, the women's babies had 0.41 IU less vitamin D in their blood.

The link between these two types of air pollution and low vitamin D levels was strongest for women exposed to the pollution in her third trimester.

According to background information in the study, recent research has found links between insufficient prenatal vitamin D and the development of asthma, allergies and other auto-immune conditions in children.

"Gestational exposure to ambient urban air pollution, especially during late pregnancy, may contribute to lower vitamin D levels in offspring," the authors wrote. "This could affect the child’s risk of developing diseases later in life."

The study was published August 17 in the Journal of Clinical Endocrinology and Metabolism. The authors declared no conflicts of interest. The research was funded by a long list of sources, starting with grant from the French Agency for Environment Security.

Other funders include the Foundation for Medical Research, the French Ministry of Research IFR program, the National Institute of Health and Medical Research Nutrition Research Program, the French Ministry of Health Perinatality Program, the French National Institute for Population Health Surveillance, the Paris-Sud University, the French National Institute for Health Education, Nestlé, Mutuelle Générale de l’Education Nationale, the French-Speaking Association for the Study of Diabetes and Metabolism (Alfediam), and the National Agency for Research.

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Review Date: 
September 12, 2012