[Sudden infant death syndrome: clinical aspects of an underdiagnosed disease]

OBJECTIVES: To investigate the socio-epidemiologic characteristics of the victims of sudden infant death syndrome and to calculate its prevalence during the 1st year of life. METHODS: This is an observational, retrospective, and descriptive study based on the review of autopsy protocols and questionnaires applied to families that had cases of infants death during 1997 and 1998 in the city of Porto Alegre. RESULTS: From 335 infants who died, 21 were fulfilled SIDS criteria, although SIDS was not recorded as a cause of death on the death certificate. The infants had no previous apnea or acute disease that could justify the death. Death occurred predominantly in cold months (winter and autumn). None of the infants who died slept in supine position. Families had a low monthly income (3 minimum wages). Seventy one per cent the mothers were smokers and 42% used alcohol during the pregnancy. SIDS prevalence was estimated as 6.3% from the total number of deaths, and the specific mortality coefficient for SIDS was 4.5:10,000 live births. CONCLUSIONS: The profile identified for infants at risk is similar to that reported in the literature. However, since SIDS is often misdiagnosed in our community, it does not appear in the statistics about infant mortality. As a consequence, there have never been campaigns to reduce the risk of death due to this syndrome.