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Current Trends Sudden Infant Death Syndrome as a Cause of Premature Mortality United States, 1984 and 1985

Of the 10 leading causes of years of potential life lost before age 65 (YPLL), three occur primarily in the first year of life: congenital anomalies ranked fifth, prematurity ranked sixth, and sudden infant death syndrome (SIDS) ranked seventh (1). The previous report on SIDS included preliminary estimates of 1984-1986 YPLL associated with SIDS (2). This report, based on final mortality data, compares estimates of SIDS-associated YPLL by race and sex for 1984 and 1985 with those for 1980-1983.

To estimate YPLL for SIDS as reported in Table V (3), national death certificate data were compiled from the National Center for Health Statistics (NCHS), CDC, national mortality computer tapes. Deaths were attributed to SIDS if both the underlying cause of death was classified as category 798.0 (according to the International Classification of Diseases, Ninth Revision (ICD-9)) and the death occurred during infancy (less than 1 year of age). SIDS was divided into groups by race* and sex of infant. YPLL was calculated by averaging the age at death for each subgroup** for this study period. Because trends in YPLL from infant deaths are affected by the annual number of live births, the average annual SIDS-attributable YPLL per 1000 live births was also calculated.

In 1984, 5245 SIDS cases were reported, accounting for 339,517 YPLL (Table 1). Similarly, in 1985, 5315 SIDS deaths were reported, accounting for 344,114 YPLL. In both years, SIDS was the seventh leading cause of YPLL (1).

Males accounted for 61% of SIDS-attributable YPLL for 1984-1985 (Table 1), and white males had the highest proportion (44%) of SIDS-attributable YPLL for this period. Seventy percent of SIDS-attributable YPLL occurred among whites, 26% among blacks, and 3% among Native American and other races. The average annual YPLL rates per 1000 live births were highest for blacks and Native Americans (Table 2). However, rates for all racial/sex groups except white males and others (not including Native Americans) decreased slightly from those for 1980-1983. Reported by: Pregnancy Epidemiology Br and Research and Statistics Br, Div of Reproductive Health, Center for Health Promotion and Education, CDC.

Editorial Note

Editorial Note: To decrease or eliminate misdiagnoses, the term "SIDS" was defined by the Second International Conference on Causes of Sudden Death in Infants held in Seattle, Washington, in 1969 (4). Formerly called a "crib death" or "cot death," SIDS is now defined as "the sudden death of any infant or young child which is unexpected by history, and in which case a thorough postmortem examination fails to demonstrate an adequate cause of death" (4). Confirmation of SIDS requires a thorough history, a postmortem examination, and a death scene investigation (5,6). Although a postmortem examination is needed to diagnose SIDS, the percentage of autopsy- confirmed diagnoses varies by state. Data from the NCHS mortality tapes from 1980 to 1985 show that the autopsy rate has increased overall during this time. In 1980, the SIDS autopsy rate by state ranged from 10% to 100% (median: 82%). By 1984, it had increased to 25%-100% (median: 92%), and by 1985, to 47%-100% (median: 93%). Appropriate investigation and diagnosis of SIDS may assist in allocating health-care resources for prevention programs.

Although the continuing high male:female ratio of YPLL is consistent with findings of most epidemiologic studies of SIDS (7,8), the slight increases in YPLL rates among white males since 1980-1983 should be monitored to determine a possible emerging trend. These findings underscore the usefulness of evaluating trends in YPLL that are based on the annual number of live births in any given group.

Despite a decline in YPLL per 1000 live births for blacks, racial differences in SIDS-attributable YPLL remain a concern. The 1984-1985 rate of SIDS-attributable YPLL for blacks was 1.9 times, and for Native Americans, 1.7 times that for whites. This discrepancy was also demonstrated in a study of birthweight-specific infant mortality among Native Americans. Native Americans had a SIDS postneonatal mortality risk 3.5 times that of whites (9). These data suggest a need for further investigation of race and gender differences for SIDS.


  1. CDC. Changes in premature mortality--United States, 1979-1986. MMWR 1988;37:47-8.

  2. CDC. Premature mortality due to sudden infant death syndrome--United States, 1980-1986. MMWR 1987;36:236-8.

  3. CDC. Introduction to Table V: premature deaths, monthly mortality, and monthly physician contacts--United States. MMWR 1982;31:109-10,117.

  4. Beckwith JB. Discussion of terminology and definition of sudden infant death syndrome. In: Bergman AB, Beckwith JB, Ray CG, eds. Sudden infant death syndrome. Proceedings of the Second International Conference on Causes of Sudden Death in Infants. Seattle, Washington: University of Washington Press, 1970.

  5. Jones AM, Weston JT. The examination of the sudden infant death syndrome infant: investigative and autopsy protocols. J Forensic Sci 1976;21:833-41.

  6. Lewman LV. Oregon's model system: a statewide approach. Pediatr Ann 1974;Nov:44-54.

  7. Beckwith JB. The sudden infant death syndrome. Rockville, Maryland: US Department of Health, Education, and Welfare, Public Health Service, Health Services Administration, 1976; DHEW publication no. (HSA)76-5137.

  8. Peterson DR, van Belle G, Chinn NM. Epidemiologic comparisons of the sudden infant death syndrome with other major components of infant mortality. Am J Epidemiol 1979;110: 699-707.

  9. Vanlandingham MJ, Buehler JW, Hogue CJR, Strauss LT. Birthweight-specific infant mortality for Native Americans compared with whites, six states, 1980. Am J Public Health 1988; 78:499-503. *This is the first report that divides YPLL for persons of other races into Native Americans (American Indians, Aleuts, and Eskimos) and others (Chinese, Japanese, Hawaiian, Filipino, and others). **YPLL = T (65-(A/365.25)), where T = total number of infant deaths for subgroup (year, race, and sex) and A = average age at death in days for that subgroup.

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