Generalized joint hypermobility and black admixture in school children of Bahia, Brazil.

Joint hypermobility was investigated in a sample of 3,000 school children, ages 6--7 years, in Bahia, Brazil. A sampling method was designed to assure an equal number of 50 children in the smallest size classes, when age, race, and sex were held constant. Race was classified in five subgroups to assess the proportion of black admixture. The overall frequency of generalized joint hypermobility was 2.3%. The darker the children the lower the frequency of affected children. However, this racial effect was also associated with age: The highest frequency of generalized joint hypermobility was among the youngest and less black mixed children, whereas among the oldest and darker children there was no case of joint hypermobility.