Mothers’ fatty acid levels linked to children’s risk of asthma

A specific fatty acid molecule in the blood of pregnant women may be linked to the risk of their children developing early childhood asthma and respiratory infections.

This is shown in a new study by researchers at the University of Copenhagen and Copenhagen Prospective Studies on Asthma in Childhood, COPSAC, at the Danish Pediatric Asthma Center at Herlev and Gentofte Hospital.

The study examined the fatty acid molecule 12-HETE in the blood of pregnant women. According to the researchers, the occurrence of early childhood asthma during the child’s first ten years of life was 62 percent higher if the mother had no measurable amounts of 12-HETE in her blood during pregnancy, compared with mothers in whom the substance could be measured.

However, the researchers emphasize that the study shows a statistical association. It therefore cannot be concluded that a lack of 12-HETE directly causes asthma.

Early childhood asthma, also known as asthmatic bronchitis, affects 10 to 20 percent of all children, according to the researchers, and is one of the most common reasons for hospital admissions among children aged 0 to 3.

Asthma researcher and clinical professor Bo Chawes from the Department of Clinical Medicine and COPSAC says that the researchers show, for the first time, a link between a specific fatty acid molecule in pregnant women and the child’s risk of developing asthmatic bronchitis.

The study also shows that children of mothers without measurable 12-HETE in their blood during pregnancy more often have multiple respiratory infections and an altered bacterial composition in their airways. As early as when the child is one month old, the researchers could see differences in bacterial composition and immune response in the airways.

According to Bo Chawes, the results suggest that 12-HETE may play a role in the early maturation of the child’s immune system. If the level of certain fatty acids is too low very early in life, it may possibly affect the immune system and the microbiome in the lungs, thereby increasing susceptibility to respiratory infections and asthma.

The researchers followed several hundred mothers and children over a ten-year period. The study is based, among other things, on data from the Danish COPSAC2010 cohort with 738 mothers and 700 children, as well as the American VDAART cohort with 881 women and 810 children.

In the Danish part of the study, the researchers measured the level of 12-HETE in blood samples from pregnant women in the 24th week of pregnancy and then followed the children’s health with a focus on asthma and respiratory infections. The results were subsequently tested in the American cohort.

The study also examined the link between 12-HETE and the effect of omega-3 supplements during pregnancy. Previous studies have shown that omega-3 may in some cases have a protective effect against childhood asthma.

In the new study, the researchers found that omega-3 supplements apparently only reduced the occurrence of asthma in children of mothers in whom 12-HETE could be measured. In this group, the occurrence of early childhood asthma was 58 percent lower compared with the group that received a placebo. The researchers found no difference when the fatty acid could not be measured in the mothers.

Bo Chawes points out that the results may add nuance to the understanding of who benefits from omega-3 supplements during pregnancy. However, it is still too early to use the results clinically, for example to advise pregnant women about dietary supplements.

The researchers emphasize that, among other things, more specific measurement values for 12-HETE are needed before the results can be used in practice.

According to Bo Chawes, the study may be a first step toward more personalized and precise prevention of childhood asthma, because 12-HETE could potentially serve as a biomarker.

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