Sudden infant death syndrome: risk factor profiles for distinct subgroups.
The authors investigated risk profiles of sudden infant death syndrome (SIDS) as a function of age at death. A case-control study carried out in the Tyrol region of Austria enrolled 99 infants who died of SIDS between 1984 and 1994 and 136 randomly selected controls. Early and late SIDS (< 120 days of age vs. > or = 120 days) were defined according to the clear-cut bimodal age-at-death distribution. Inadequate antenatal care, low parental social and educational level, and the prone sleeping position were risk conditions that applied to both early and late SIDS. A marked seasonal variation (winter preponderance) was the most outstanding feature of late SIDS. A gestational age of < 37 weeks (odds ratio (OR) = 8.4, 95% confidence interval (CI) 2.6-26.0), repeated episodes of apnea (OR = 5.7, 95% CI 1.2-27.0), low birth weight (< 2,500 g) (OR = 3.4, 95% CI 1.1-11.0), a family history of sudden infant death (OR = 2.9, 95% CI 1.1-7.5), and maternal smoking during pregnancy (OR = 2.2, 95% CI 1.0-4.5) were associated with early SIDS. This study identified two distinct subgroups of SIDS infants characterized by different risk conditions and ages at death. These results underline a multiple-cause hypothesis for SIDS etiology which involves a genetic predisposition, immaturity in the first months of life, and environmental factors acting at various ages.
Kohlendorfer
U
U
Department of Pediatrics, University Hospital of Innsbruck, Austria.
Kiechl
S
S
Sperl
W
W
D000328:Adult; D001317:Austria / Q000453:epidemiology; D001344:Autopsy / Q000706:statistics & numerical data; D001719:Birth Certificates; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D008423:Maternal Age; D015999:Multivariate Analysis; D015995:Prevalence; D016684:Prone Position; D011897:Random Allocation; D012307:Risk Factors; D012621:Seasons; D017678:Sex Distribution; D012890:Sleep; D013398:Sudden Infant Death / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D015996:Survival Rate