摘要：We investigated the effect of maternal smoking during pregnancy on the relative risk of sudden infant death syndrome (SIDS) by linking data from Georgia birth and death certificates from 1997 to 2000. We estimated the effect of misclassifying smokers as non-smokers and the effect of being misclassified on SIDS rates, and we calculated the fraction of cases caused by exposure. Of all SIDS cases, 21% were attributable to maternal smoking; among smokers, 61% of SIDS cases were attributable to maternal smoking. Maternal smoking during pregnancy is associated with a significantly increased risk of SIDS. Sudden infant death syndrome (SIDS) is the sudden death of an infant aged younger than 1 year that remains unexplained after a thorough case investigation that includes an autopsy, a death scene investigation, and a review of the clinical history of the parents and the infant. 1 Known risk factors for SIDS include sleeping in the prone position, being exposed to smoke pre- and postnatally, sharing a bed with a mother who smokes, hyperthermia, lack of breastfeeding, and sleeping on soft surfaces. 2 Even though the rate of SIDS cases in the United States decreased by 40% from 1992 to 1999, the surgeon general reports that smoking rates during pregnancy may be as high as 22%. 3 As shown by Guntheroth in low-income women, 4 prenatal exposure to smoking likely means exposure to smoking during pregnancy and after pregnancy as well. According to that study, of the low-income women who smoked, most continued to smoke throughout their pregnancy; of those who quit, most returned to smoking during the pregnancy or shortly after delivery. Studies have also shown that, on birth certificates, mother’s smoking status has been found to be substantially misclassified. 5 Dietz et al. 5 used a 2-sample capture–recapture method to estimate the completeness of recorded prenatal smoking on birth certificates in Georgia and found that whereas the reported maternal smoking from 1993 to 1995 was 13.3%, their estimate by the capture–recapture method was 20.8%. Because underreporting and misclassification of smoking status leads to a biased estimate of the smoking–SIDS relationship, we linked birth and infant mortality records from the state of Georgia to examine the effect of maternal smoking during pregnancy on the frequency of SIDS cases in Georgia.
