A CASE-CONTROL STUDY OF SMOKING AND SUDDEN-INFANT-DEATH-SYNDROME IN THE SCANDINAVIAN COUNTRIES, 1992 TO 1995

Aim-To establish whether smoking is an independent risk factor for sud den infant death syndrome (SIDS), if the effect is mainly due to prena tal or postnatal smoking, and the effect of smoking cessation. Methods -The analyses were based on data from the Nordic epidemiological SIDS study, a case-control study with 244 cases and 869 controls. Odds rati os were computed by conditional logistic regression analysis. Results- Smoking emerged as an independent risk factor for SIDS, and the effect was mainly mediated through maternal smoking in pregnancy (crude odds ratio 4.0 (95% confidence interval 2.9 to 5.6)). Maternal smoking sho wed a marked dose-response relation. There was no effect of paternal s moking if the mother if the mother did not smoke. Stopping or even red ucing smoking was beneficial. SIDS cases exposed to tobacco smoke were breast fed for a shorter time than non-exposed cases, and feeding dif ficulties were also more common. Conclusions-Smoking is an independent risk factor for SIDS and is mainly mediated through maternal smoking during pregnancy. Stopping smoking or smoking less may be beneficial i n reducing the risk of SIDS.