ATOPIC-DERMATITIS AND BIRTH FACTORS - HISTORICAL FOLLOW-UP BY RECORD LINKAGE

Objective: To study if factors at birth are associated with later deve lopment of atopic dermatitis. Design: Historical follow up by record l inkage from Danish medical birth register. Children were followed up f or 5.5 to 8.5 years. Second historical follow up study comprising ques tionnaire to mothers of singleborn children 6.5 to 9.5 years after bir th. Setting: Private dermatology clinics and dermatology and paediatri c departments in the municipality of Aarhus, Denmark, Subjects: 7862 s ingletons born in hospital between 1 January 1984 and 31 December 1986 to mothers living in the municipality of Aarhus. Questionnaires sent to 985 mothers. Main outcome measures: Gestational age, birth weight, parity, and age of mother at the time of birth. Atopy in children diag nosed by specialists in dermatology and physicians. Family size; diagn osis of atopic dermatitis, allergic rhinitis, and asthma; family predi sposition; and mothers' smoking habits during pregnancy determined fro m questionnaires. Results: Of 7862 children, 403 were diagnosed as hav ing atopic dermatitis by a specialist; the cumulative incidence at age 7 was 5.6%. High gestational age and low parity were associated with an increased risk of atopic dermatitis, Among 985 children atopic derm atitis had been diagnosed by any physician in 184; the cumulative inci dence at age 7 was 18.7%. High birth weight high gestational age, and family history of atopy were associated with increased risk of atopic dermatitis. Conclusion: In both studies the incidence of atopic dermat itis was associated with high gestational age and in one with high bir th weight also. The causes for these associations are at present unkno wn but may indicate that even during gestation factors associated with atopic dermatitis influence maturation.