This study investigated the prevalence of overweight [body mass index (BMI) > or = 25 kg m-2] in young adulthood among international adoptees. The prevalence of overweight among adoptees from various countries of origin was compared with that in a large group of non-adopted individuals. All 275,026 young men born in 1973-1977 and living in Sweden at 17 y of age were included. A record linkage was made between the Military Service Conscription Register and several population registers. Data on BMI at 18 y of age were obtained from military conscription examinations conducted in 1991-1995. BMI was missing for 12.7% of 2400 adoptees and 10.8% of 263,173 non-adoptees. Among 623 adoptees from Latin America 21.5% (95% confidence interval 18.3-24.7) were overweight, with a particularly high prevalence of overweight among the 266 adoptees from Chile (28.6%, 23.1-34.0). Among 502 adoptees from the Indian subcontinent 8.4% (5.9-10.8) were overweight and the prevalence of overweight was 8.8% (5.7-12.0) among 317 adoptees from India. Among 817 adoptees from the Far East 12.0% (9.8-14.2) were overweight and the prevalence of overweight was 10.9% (7.9-13.9) among 404 from South Korea. The corresponding figure was 14.1% (14.0-14.2) among the non-adopted individuals.
Conclusion: These differences in prevalence of overweight between various groups of adoptees and between adopted and non-adopted subjects are remarkable and are probably due to diversity in genetic susceptibility to overweight.