NEW YORK (Reuters Health) – The risk of asthma is higher in children who have coeliac disease or rheumatoid arthritis than among children without either of these autoimmune diseases, according to analysis of Finnish population data. This finding implies that T-helper 1 and T-helper 2 diseases often coexist.
Dr. Jukka Kero, of the Ruprecht-Karls-Universitat Heidelberg in Germany, and colleagues note that "asthma is generally regarded as a disease with strong Th2-type cytokine expression, whereas in autoimmune disorders…Th1-type expression is seen." It would seem logical that the two types of disease would not coexist, if Th1 and Th2 cells are cross-regulatory.
To investigate, the researchers linked data from the Finnish Medical Birth Register for 1987 with data from national and regional health registers between 1987 and 1994. Among the more than 60,000 individuals born in 1987, the cumulative incidence per 1000 individuals was 34.2 for asthma, 1.9 for coeliac disease, 3.0 for insulin dependent diabetes mellitus, and 1.3 for rheumatoid arthritis.
As the investigators report in the Journal of Allergy and Clinical immunology for November, the cumulative incidence of asthma was 24.6% among children with coeliac disease, 5.0% for those with diabetes, and 10.0% for those with arthritis. The differences in asthma incidence were significant for rheumatoid arthritis (p = 0.016) and coeliac disease (p = 0.001), and could not be explained by social class.
"Taken together, these data demonstrate that the existence of T-helper 1-type disease does not reduce the incidence of asthma," Dr. Kero's group writes. The coexistence of the two disease types may be related to common environmental factors, they add.
J Allergy Clin Immunol 2001;108:781-783.