[Children and adolescents with Down syndrome in Sør-Trøndelag 1978-97].

Ultrasound examination offered to nearly all pregnant women in Norway may lead to the identification of fetuses with Down's syndrome. This may lead to termination of pregnancies and to a reduction in the prevalence of live-borns with Down's syndrome. In a retrospective study of hospital records we have examined the prevalence of Down's syndrome, associated malformations and diseases during the last 20 years. 68 children and adolescents with Down's syndrome were identified. 43 were born 1988-97 (1.16 per 1,000 births) and 25 1978-87 (0.8 per 1,000 births; p = 0.13). Congenital heart defects were diagnosed in 33 children (49%). Five children (7.4%) had died by the end of 1997, four with a cardiovascular defect. Four children had moved out of the region. Among 59 persons alive at the time of study, 11 (19%) were treated for hypothyroidism, 26 (44%) had been hospitalised because of infections, and 14 (20%) suffered from problems with sleep obstruction. 23 (39%) had impairments in hearing and 30 (51%) in vision. Ten children (18%) had a weight-for-height above the 97.5 percentile of standard growth charts for Norwegian children. Serum concentration of zink was below reference values in 15 children. We conclude that the prevalence of livebirths with Down's syndrome was not reduced in 1988-97 compared to 1978-87. Children with Down's syndrome have a wide range of somatic disorders and need close and systematic medical follow-up.