Being obese during pregnancy dramatically increases the risk of
your child having asthma before their tenth birthday, a new study
has found.
In collaboration with Swedish researchers, Dr Adrian Lowe from
Murdoch Childrens Research Institute and University of Melbourne,
found there was a clear increase in the risk of childhood asthma
with increasing level of obesity in the mother, with the children
of very obese mothers having a 57% increase in the odds of using
asthma medications between eight and 10 years of age.
Researchers examined the association between mothers' body mass
index (BMI) in early pregnancy and the risk that her child would
either need asthma medications or be hospitalised for asthma up to
10 years of age.
In the largest study on the association between maternal obesity
during pregnancy and the risk of childhood asthma, researchers drew
on data collected by the Swedish National Board of Health and
Welfare. This research, which was initiated when Dr Lowe was a
visiting researcher at Umea University in Sweden, studied over
189,000 children born to 129,239 mothers in Stockholm, Sweden.
In a letter to the editor in the Journal of Allergy and Clinical
Immunology, researchers stated children of very obese mothers had
the highest rate of asthma medications use (10.3%), but even
children of mothers who were only slightly overweight had an
increased risk (7.8%) when compared to children born to mothers
with normal weight.
Lead author, Dr Adrian Lowe, said the link could potentially
explain some of the increase in incidences of childhood asthma
during recent decades.
"The prevalence of both asthma and obesity has increased over
the past five decades in westernized countries, as has the
proportion of mothers who are obese or overweight. If the
association between maternal BMI and asthma risk in children is
casual, it might explain between 11 and 13 per cent of childhood
asthma," Dr Lowe said.
The study hypothesized that maternal obesity may increase the
risk that a child will develop asthma by increasing the child's own
risk of obesity, influencing the infant's immune system towards
allergies during pregnancy or by changing the metabolic balance of
the child.
"Although the underlying mechanism to explain these results
remains unclear, these results suggests that, if successful, public
health campaigns to combat obesity may have a beneficial effect on
the rate of childhood asthma."