Impact of specific medical interventions on reducing the prevalence of mental retardation.
OBJECTIVE
To explore the impact of medical interventions on reducing the prevalence of mental retardation (MR) in the United States over the last 50 years.


METHODS
We reviewed the medical literature and other data from 1950 to 2000 to construct estimates of the general and condition-specific prevalence of MR in the United States over time. We further explored the existing literature to document historically important influences on condition-specific prevalence, including the year that an effective intervention was introduced, the likelihood of success of the intervention, and the availability of such interventions nationwide. Specific conditions included congenital syphilis, Rh hemolytic disease of the newborn, measles, Haemophilus influenzae type B meningitis, congenital hypothyroidism, phenylketonuria, and congenital rubella syndrome.


METHODS
Twentieth-century North America.


METHODS
Children with MR or 1 of the 7 specific conditions listed earlier.


METHODS
Case-specific and general prevalence of MR from 1950 to 2000.


RESULTS
The prevalence of MR caused by a number of specific medical conditions has decreased sharply over the last 50 years. However, the incidence of each of these conditions is relatively low, and cases of MR due to these conditions represent, at most, 16.5% of the total number of cases of MR in 1950.


CONCLUSIONS
Although specific medical interventions have prevented thousands of cases of MR, their contribution to the overall prevalence of MR is relatively small.
Brosco
Jeffrey P
JP
Department of Pediatrics, Miller School of Medicine, University of Miami, Miami, Fla 33101, USA. jbrosco@miami.edu
Mattingly
Michael
M
Sanders
Lee M
LM
D003409:Congenital Hypothyroidism / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D004899:Erythroblastosis, Fetal / Q000188:drug therapy / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D008403:Mass Screening / Q000379:methods; D008457:Measles / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D008583:Meningitis, Haemophilus / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D015995:Prevalence; D012410:Rubella Syndrome, Congenital / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D013590:Syphilis, Congenital / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D014481:United States / Q000453:epidemiology