title: Twenty-year birth prevalence of Down syndrome in Cape Town, South Africa.
abstract: The 20-year birth prevalence of Down syndrome in Cape Town, South Africa, was determined. All cases delivered to mothers in Cape Town, plus terminations following prenatal diagnosis, between 1 January 1974 and 31 December 1993 were ascertained. There were 784 Down syndrome pregnancies, of which 95% were trisomies. The 32 terminations comprised 18.3% of the white, 5.8% of the coloured (mixed race) and 1.4% of the black cases. The overall prevalence rate was 1.49 per 1000 (white 1.88, coloured 1.54 and black 1.29 per 1000). Analysis for linear trends showed a significant decline in rates for the total population and for whites, a downward trend for coloureds, but no decline for blacks. Over the last 5-year period the prevalence rates in all three population groups were 1.3 per 1000. An increasing risk with advancing maternal age was confirmed, but no maternal age-specific differences in rates by race were demonstrated.
authors.affiliation: Department of Psychiatry, Groote Schuur Hospital, Cape Town, South Africa.
authors.forename: C
authors.initials: C
authors.lastname: Molteno
authors.forename: R
authors.initials: R
authors.lastname: Smart
authors.forename: D
authors.initials: D
authors.lastname: Viljoen
authors.forename: R
authors.initials: R
authors.lastname: Sayed
authors.forename: A
authors.initials: A
authors.lastname: Roux
mesh_terms: D000028:Abortion, Induced; D000293:Adolescent; D000328:Adult; D001741:Black or African American; D044383:Black People; D003430:Cross-Sectional Studies; D004314:Down Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D008875:Middle Aged; D011296:Prenatal Diagnosis; D044469:Racial Groups; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D044465:White People