Incidence na dprevalence of Down's syndrome in the city of Ribeirão Preto, São Paulo (Brazil, 1972.

An incidence rate of 1.66 was determined for Down's syndrome by a check of hospital birth records in the city of Ribeirão Preto for the year 1972, based on the premise that most births in the population residing in the urban area of Ribeirão Preto occur in hospitals. The prevalence rate was estimated as being 25.2. A search for affected individuals born before 1972 was carried out by physical examination of all persons receiving medical care or educational and social assistance from several city institutions. The prevalence value must be considered as an underestimate since the methods used allowed only for the detection of cases which were getting some kind of assistance.