Bacteria Are Linked to Asthma in Girls

A new study reports that there appears to be an association between Chlamydia pneumoniae infection and wheezing, particularly in girls.

Researchers from Uppsala University (Sweden) studied data from 1,581 children four years old, who had been followed since birth. The children had been tested for antibodies to C pneumoniae and to common allergens. In all, 159 (10.1%) had detectable levels of immunoglobulin G (IgG) antibodies to C pneumoniae. There was no significant difference in incidence between boys and girls. However, at one year old (in girls), C pneumoniae immunoglobulin C (IgC) was tied to an odds ratio of wheezing of 3.4. By the age of four years, the corresponding ratio was 2.01.

In those with the highest IgC levels, the association was even more pronounced. When further stratified by immunoglobulin E (IgE) sensitization to allergens, girls without sensitization were at significantly increased risk of wheezing compared to those who were IgE sensitized. The findings were reported in the December 2006 issue of Thorax.

"If the result of our study turns out to be true, that there is an association between infections with C pneumoniae and asthma,” said lead author Dr. Erik Normann of the department of women's and children's health at Uppsala University, "it is possible that a vaccine against C pneumoniae might reduce the prevalence of asthma.”

Recent attention has been directed at the role of infections with the atypical bacteria Mycoplasma pneumoniae and C pneumoniae as agents capable of triggering asthma exacerbations and potentially as inciting agents for asthma. There is abundant evidence that asthma is frequently exacerbated by infectious agents, and several respiratory syncytial viruses have been implicated in the inception and exacerbation of asthma.



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