Could maternal obesity cause child-hood asthma?
Published Online: September 29, 2011
The rates of both asthma and obesity have increased in recent decades, raising the possibility that these two epidemics may be linked. One of the consequences of the rising rates of obesity is that a greater proportion of mothers are starting their pregnancies either overweight or obese. Maternal obesity may increase the risk that a child will develop asthma by a) increasing the child’s own risk of obesity; b) influencing the infant’s immune system towards allergies during pregnancy; c) changing the metabolic balance of the child. Maternal obesity also increases the risk of pregnancy complications, including need for delivery by caesarean section, which may increase the child’s risk of allergic disease.
In a Letter to the Editor in The Journal of Allergy & Clinical Immunology (JACI), Lowe et al examined the association between mothers’ body mass index (BMI) and asthma risk in the child. Information on mothers’ height and weight in early pregnancy was collected for all children born in Stockholm, Sweden, between 1998-2009, as was data on the child’s use of asthma medications and hospitalisation for asthma. A total of 189,783 children were included, making this the largest study of this association to date.
The authors found that there was a clear increase in risk of childhood asthma with increasing level of obesity in the mother. Children of very obese mothers (BMI of 35+kg/m2) had the highest rate of asthma medications use, but even children of mothers who were only slightly over weight (BMI of 25-30kg/m2) had an increased risk when compared to children born to mothers with normal weight.. This effect was not due to increased risk of pregnancy related complications in obese mothers, as adjustment for these complications did not materially alter the associations. Although the underlying mechanism to explain these results remains unclear, these results suggest that, if successful, public health campaigns to combat obesity may have a benificial effect on the rate of childhood asthma.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.