Pediatric Medicine

Asthma comes into play by ear

Children with recurrent ear infections are more prone to asthma

By Graham Furness

At first glance it may not seem like ear infections and asthma have much in common. Strangely enough there seems to be a connection. Children with recurrent ear infections may have an increased risk of developing asthma, says a study published in the May issue of CHEST. In fact, the baffling relationship between infection, allergy and autoimmune disease has been the subject of much research lately. While some studies suggest getting dirty is the best way to keep a healthy immune system, others indicate that specific infections increase the risk of immune disorders. This study is one of several to find a link between infection and later asthma or dermatitis.

"The prevalence of ear infections has increased significantly over the years, paralleling the rise in asthma rates. Our study confirms the association between the two conditions, showing that ear infections in early childhood may lead to asthma later in life," said lead researcher Kamal Eldeirawi, of the University of Illinois in Chicago. "It's possible that specific viruses or bacteria that cause recurrent ear infections may play a major role in the development of asthma. It also is possible that antibiotics that are commonly used to treat ear infections increase the risk of asthma, but more research is needed in this area."

In a cross-sectional study, researchers used data from the Third National Health and Nutrition Examination Survey, conducted from 1988 to 1994, to examine the association of ear infections with asthma or wheezing. The study population included 7,538 children aged two to 11 with complete medical histories of asthma, wheezing, and ear infections, as well as parental education and tobacco use history.

Children with three or more ear infections during their lifetime were twice as likely to have asthma compared to those without ear infections. Wheezing also was 1.55 times more likely in children without asthma but with a history of ear infections.

More boys had asthma than girls, and the disease's prevalence also varied by age group, with the highest rate reported for children aged six to eight and the lowest for children aged two to three. Participants whose parents had a history of asthma or hay fever were also more prone to asthma.

Finally, the rate of ear infections increased with parental education level. "Well-educated parents may have better access to healthcare and, therefore, may be more knowledgeable about ear infections and, thus, more likely to report ear infections," said Mr Eldeirawi.

These results don't rule out an antibiotic effect on asthma rates. The only way to tease apart the confounding factors would be a prospective double-blind study in which some children with ear infections are left untreated. Considering this could leave the kids open to serious complications like meningitis, the ethics of such a study would be questionable.