ETHNIC-DIFFERENCES IN THE INCIDENCE OF THE SUDDEN-INFANT-DEATH-SYNDROME (SIDS) IN VICTORIA, AUSTRALIA 1985-1989

In order to describe ethnic differences in the incidence of the sudden infant death syndrome (SIDS) records of all livebirths in the State o f Victoria, Australia, 1985-1989, excluding those who died in the firs t month of life, were linked to death certificates. Cases were defined as infants dying with a diagnosis of SIDS between 1 month and 1 year of age (n = 601) from the cohort of 308052 neonatal survivors. Ethnici ty was defined by the mother's country of birth. The SIDS incidence wa s 2.04/1000 in infants of Australian-born mothers. The relative risk o f SIDS was 0.28 (95% confidence interval (CI) 0.15,0.55) in infants wh ose mothers had been born in Southern Europe and 0.48 (95% CI 0.29,0.7 8) in infants whose mothers had been born in Asia. SIDS in infants of Australian-born mothers was associated with low maternal age, high par ity, marital status other than married, male sex, multiple birth, low birthweight and preterm birth. After adjustment for those factors in a case-control analysis using a logistic regression model the adjusted odds ratio for SIDS was 0.34 (95% CI 0.17, 0.69) comparing infants who se mothers were born in Southern Europe with infants of Australian-bor n mothers, and 0.60 (95% CI 0.35, 1.04) for infants whose mothers were born in Asia, compared with infants of the Australian-born. Thus ther e are substantial ethnic differences in SIDS which are not explained b y,the classic social and perinatal risk factors.