Predisposition to atopic symptoms to inhaled antigens may protect from childhood type 1 diabetes

OBJECTIVE - To assess the inverse association between type 1 diabetes and asthma to establish whether environmental and/or genetic factors predisposing to asthma or to atopic symptoms to inhaled antigens protect from diabetes. RESEACH DESIGN AND METHODS - Questionnaires were returned by 306 probands with childhood type 1 diabetes, their 506 nonaffected siblings, and 406 age- and sex-matched unaffected population control subjects. The main outcome measures were self-reported physician-diagnosed asthma and atopic symptoms to animal dust and pollen. RESULTS - Risk of diabetes was inversely associated with asthma (odds ratio 0.49 [95% CI 0.24-1.00]), allergy to animal dust (0.67 [0.45-0.99]), and to a lesser degree to pollen (0.74 [0.51-1.07]) when the probands were compared with the population control subjects. Among the children of the families of an affected proband, the risk of diabetes appeared to be inversely associated with asthma (0.54 [0.27-1.09]) but not With allergy to animal dust (0.99 [0.66-1.47]) nor allergy to pollen (0.88 [0.62-1.27]). CONCLUSIONS - The frequency of asthma and atopic symptoms to some inhaled antigens is decreased in individuals with childhood type 1 diabetes. Factors predisposing to atopic symptoms to inhaled antigens may protect from childhood type 1 diabetes.