Dr. Petri S. Mattila, of Helsinki University Central Hospital, Finland, and colleagues assessed the frequency of asthma and atopy among 306 patients with childhood diabetes, their 506 non-affected siblings, and 406 matched controls.

When the diabetic children were compared with the controls, the researchers observed an inverse association between the risk of diabetes and asthma (odds ratio = 0.49) and allergy to animal dust (odds ratio = 0.67). The risk was also inversely associated, though to a lesser degree, with allergy to pollen (odds ratio = 0.74).

When the diabetic children were compared with their non-affected siblings, the risk of diabetes was inversely associated with asthma (odds ratio = 0.54), but not with allergy to animal dust (odds ratio = 0.99) or pollen (odds ratio = 0.88).

"This suggests that the probands and their unaffected siblings apparently share a genetic and/or environmental background that reduces the risk of developing animal dust allergy," Dr. Mattila and colleagues note.

Diabetes Care 2002;25:865-868.