SECULAR TRENDS OF SUDDEN-INFANT-DEATH-SYNDROME IN NORWAY 1967-1988 - APPLICATION OF A METHOD OF CASE IDENTIFICATION TO NORWEGIAN REGISTRY DATA

In Norway, towards the end of the 1980s, sudden infant death syndrome (SIDS) was the most frequent cause of infant death. Both SIDS and the total post-perinataI mortality rates had increased. This paper present s a procedure for identifying SIDS from death certificates. Supplement ed with additional information, a database was established to evaluate secular trends of SIDS and for further analytical research. The Medic al Birth Registry of Norway comprises 1.3 million births from 1967 to 1988. Of these, 5447 infants died in the post-perinatal period. The ca use of death was reviewed by an expert panel and 1984 cases of SIDS we re retrieved. Low maternal age, higher birth order, male gender, and l ower birthweight were confirmed as risk factors for SIDS. In 1988, the rate for SIDS and for total post-perinatal deaths reached 2.69 and 5. 02 per 1000 infants at risk. The incidence of SIDS increased 2.2 times from the period 1967-1971 to the period 1987-1988. Adjusted for mater nal age, birth order, and birthweight, the odds ratio was 3.1. The inc rease is due to factors not yet accounted for. Adjusted mortality rate s for the other post-perinatal deaths were not different from the crud e rates.