Lung Deficits Caused by Smoking Plus Early Asthma

A study has shown that early onset of asthma plus exposure in the womb to maternal smoking were associated with large deficits in the lung function of children. The study appeared in the March 15, 2003, issue of the American Journal of Respiratory and Critical Care Medicine.

Investigators examined the medical history, tobacco smoke exposure, and lung function in almost 6,000 participants in the Children's Health Study. They found that children exposed in utero to smoke who had late onset of asthma (after age five) showed lung deficits in lung function that were smaller at age 10 and decreased by age 15, compared to children with early onset (before age five). They say this supports the hypothesis that in utero exposure and early asthma onset are synergistically associated with persistent deficits in lung function. Thus, children with early onset asthma may be a high-risk group for subsequent adverse respiratory outcomes during their lives.

The researchers, from the Keck School of Medicine at the University of California, Los Angeles (UCLA, USA), did not observe any independent effect of environmental tobacco smoke (ETS) alone on children's lung function. Almost 19% were exposed in utero to maternal smoking and 32% had received lifetime ETS exposure.