Susanne Halken

Specific immunotherapy has long-term preventive effect of seasonal and perennial asthma: 10-year follow-up on the PAT study.

Background:u2002 3‐year subcutaneous specific immunotherapy (SIT) in children with seasonal allergic rhinoconjunctivitis reduced the risk of developing asthma during treatment and 2u2003years after discontinuation of SIT (5‐year follow‐up) indicating long‐term preventive effect of SIT.

Five-year follow-up on the PAT study : specific immunotherapy and long-term prevention of asthma in children

Background:u2002 A 3‐year course of specific immunotherapy (SIT) in children with hay fever to grass and/or birch pollen significantly reduced the risk of developing asthma. To investigate the long‐term preventive effect, we performed a follow up – 2u2003years after termination of immunotherapy.

European birth cohort studies on asthma and atopic diseases: I. Comparison of study designs – a GA2LEN initiative

Background:u2002 The reasons for the rise in asthma and allergies remain unclear. To identify risk or protective factors, it is essential to carry out longitudinal epidemiological studies, preferably birth cohort studies. In Europe, several birth cohort studies on asthma and atopic diseases have been initiated over the last two decades.

European birth cohort studies on asthma and atopic diseases: II. Comparison of outcomes and exposures – a GA2LEN initiative

Background:u2002 The Global Allergy and Asthma European Network (GA2LEN) is a consortium of 26 leading European research centres committed to establish a European research area of excellence in the field of allergy and asthma.

Reply: Predictive value of family history of allergy and cord blood IgE level for allergic diseases up to adulthood Reply

The authors are happy to respond to this letter to the editor (1). We agree on most of the comments by the author of this letter. However, we do not agree that the criteria for diagnosis of eczema in our study (2) were not precise enough. That has been shown in another study from the municipality of Odense comparing different diagnostic criteria for atopic eczema in infants (3) including both the diagnostic criteria used in our study and Hanifin & Rajka criteria. Although there was a slight overrepresentation of eczema in our study among those who have completed the follow-up, we do not suspect any significant bias because there were no differences regarding other background data and environmental factors between those seen at follow-ups and those with incomplete follow-up. In the letter, it is mentioned that higher birth order and household size have been shown to be associated with lower cord blood IgE (CB IgE). This is interpreted by the author as a proof of the opinion that the effect of siblings on allergic outcome starts in utero. However, it has been shown in previous studies that several genetic and environmental factors may influence CB IgE level (4, 5). In a sample of our sample size, it is not possible to adjust for several confounding factors in performing the regression analysis. In our study, CB IgE was only predictive of eczema and food allergy that usually starts and is predominant in infancy and early childhood, and the predictive power of respiratory allergies was lost at later follow-up. The explanation for this may be that CB IgE particularly predicts IgE-mediated disease (reflecting the importance of genetic factors) and not non-IgEmediated allergic diseases, where environmental factors may play a major role (6). Aside from genetic inheritance, family history (FH) may due to a common environment also reflect the influence of relevant environmental factors on the development of allergic disease.