Relationship between type 1 diabetes and atopic diseases in a twin population.
OBJECTIVE
To study the association between type 1 diabetes and atopic diseases in a twin population.


METHODS
We performed record linkage between questionnaire-defined atopic dermatitis, asthma and hay fever, and hospital discharge diagnoses of type 1 diabetes in 54,530 Danish twins, 3-71 years of age.


RESULTS
The age- and sex-adjusted risk of atopic dermatitis was decreased in subjects with type 1 diabetes compared with nondiabetic subjects, (2.1%vs 9.9%), odds ratio (OR)= 0.23 (0.07-0.71), P = 0.011, whereas asthma and hay fever were not significantly associated with type 1 diabetes. Within twin pairs discordant for type 1 diabetes, the diabetic twin had a lower risk of atopic dermatitis relative to the nondiabetic co-twin. Genetic factors for atopic dermatitis and type 1 diabetes were negatively correlated (r = -0.30), P = 0.0009.


CONCLUSIONS
These findings substantiate the Th1 vs Th2 cell dichotomy for type 1 diabetes and atopic dermatitis, and indicate an inverse association between genetic factors for these disorders.
Department of Respiratory Medicine, Bispebjerg Hospital, Copenhagen, Denmark. sft@city.dk
S F
SF
Thomsen
D L
DL
Duffy
K O
KO
Kyvik
A
A
Skytthe
V
V
Backer
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000209:etiology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D006255:Rhinitis, Allergic, Seasonal; D018417:Th1 Cells; D018418:Th2 Cells; D014427:Twins; D055815:Young Adult