Prenatal smoke exposure increases the risk for low birth
weight in children and may contribute to asthma and airway inflammation in
these children after birth, according to a study published online.
Anders Bjerg, MD, PhD, of Sunderby Central
Hospital in Sweden, and colleagues reported on results of the International
Study of Asthma and Allergy in Childhood survey conducted in 1996. Their
research focused on 3,389 children who were available 4 years after the initial
The researchers said babies who had been exposed to
prenatal smoking had an average birth weight of 3,360 g vs. a weight of 3,571 g
for those babies who had not been exposed to prenatal smoking. Asthma rates
were increased by four to six times in children who had low birth weights and
were exposed to prenatal smoking.
Bjerg and colleagues said this is the first study to
identify a strong interaction between prenatal smoke exposure and low
birth weight on physician-diagnosed asthma in school children. The significant
augmentation of low birth weight on the association between prenatal smoking
and physician-diagnosed asthma could not be explained by confounding.
They said their findings also indicate that low birth
weight itself may contribute to decreased lung function, but the smoking
additives may increase asthma risk.
Disclosure: The researchers report no relevant financial