The number of mentally retarded--a result of steps taken by society? Changes in the age structure among mentally retarded persons in Sweden 1973-1982.

The statistics for 1983, issued by the Swedish National Board of Health and Welfare, show among other things, that the age structure among mentally retarded persons has undergone a striking change since 1973, but that the number and proportion of mentally retarded persons in the total population has not changed; there are fewer children and young persons and more adults. The author of this article considers that the reasons for the changes which have taken place during one single decade may preliminarily and hypothetically be attributed to prenatal diagnosis, improved techniques in obstetrics, the introduction of antibiotics in 1948, as well as further noticeable improvements in the medical and social care provided for mentally retarded persons. Apart from prenatal diagnosis, the measures mentioned were not intended to have exactly this result in each specific case, but if the hypotheses--totally or partly--are true, knowledge of the underlying factors will have consequences, first and foremost for future public health and medical services planning. Steps cannot be taken for the restriction or increase of the number of Caesarean sections or prenatal diagnosis, for example, with no thought of the consequences for the increase, respectively decrease in the number of mentally retarded persons. This means that the number of mentally retarded persons in society can be controlled.