A prospective clinical study of allergy progression in identical and fraternal twin pairs of children.

Abstract

Background: Understanding the factors leading to the development of allergic disease is a critical area of research. We studied the development of allergic disease in identical and fraternal twins to identify potential differences in environment versus genetic factors.

Methods: Twins aged up to 4 years were selected for inclusion in this long-term follow-up study. Regular questionnaire results, allergen levels, and other indicators were examined.

Results: A total of 80 twins were included in this study. Over time, the incidence of atopic dermatitis (AD) decreased, and the incidence of rhinitis and wheezing increased. The incidence of AD, rhinitis, and food allergy was significantly higher in identical twins than fraternal twins. The consistency of positive inhaled allergens and positive food allergens was significantly higher in the identical twins than fraternal twins. The factors influencing allergic diseases were analyzed. In the identical twins, AD was more frequent in males, those with a birth weight <2,500 g, and having siblings; rhinitis was more frequent in those living in a bungalow style home, having pets, and carpeting; and wheezing was more frequent in males, having a birth weight <2,500 g, and having siblings. In the fraternal twins, AD was more frequent in those born <37 weeks gestation, and having flowers and plants in the house; rhinitis was more frequent in those born <37 weeks gestation, those with a history of neonatal asphyxia, and having a household smoking; and wheezing was more frequent in those born <37 weeks gestation, those with a history of neonatal asphyxia, with central heating, and household smoking. No factors were found to affect the occurrence of food allergy.

Conclusions: Allergic diseases in children have a strong genetic predisposition, but are also influenced by environmental factors. The environmental factors affecting the occurrence of allergic diseases in identical and fraternal twins differ.