Age at adoption, ethnicity and atopic disorder: A study of internationallyadopted young men in Sweden

Epidemiological and laboratory studies have implied that the environment du ring early childhood is important for the risk of developing atopic disorde rs. In this study we analyzed the prevalence of asthma, hayfever and eczema among 1901 internationally adopted young men at the military-induction med ical examination in relation to indicators of their early childhood environ ment. The adopted young men who came to Sweden before 2 years of age suffer ed from asthma, hayfever and eczema significantly more often than those who came to Sweden between 2 and 6 years of age; the risk ratios (RR) were 1.6 , 2.5 and 2.1, respectively. The young men who were born in the Far East we re identified as being particularly susceptible to the development of hayfe ver and eczema, with RRs of 1.3 and 1.7. This study demonstrates that the e nvironment during the first 6 years of life has a profound influence on the risk of suffering from atopic disorders as young adults.