An investigation of the seasonality of sudden infant death syndrome in the United States

Mark Courtenay Hereward, University of Pennsylvania


Sudden Infant Death Syndrome (SIDS) is both the most common cause of post-neonatal mortality in developed countries, and of unknown cause. There is a marked winter peak in SIDS, and I investigate the correlates of that peak, to try and elucidate the causes of SIDS. I use vital statistics data sets, which are much larger than most data used in previous studies, allowing more statistical rigour in my analysis. Two sets of data are used: one (which only has death certificate information) has 26,690 SIDS deaths, and the other (which also has information from birth certificates) has 5,279 SIDS deaths. I test previous findings about SIDS before investigating seasonality of SIDS. I confirm that there are strong relationships between measures of disadvantage at the county level and the SIDS rate: poverty, non-white race, the proportion of births that were to teenagers, and the proportion of homes with bad plumbing are all associated with higher levels of SIDS. The effect on SIDS of being a member of a non-white race, however, all but disappeared in later analysis that could control for birth characteristics. Being a young mother is, nevertheless, still significant in the later analysis. I find seasonality in both month of birth and month of exposure patterns of SIDS, though the former may be an interaction of age at observation and month of exposure. I found no strong relationship between general climate of a county and the relative level of winter versus summer SIDS, although I find SIDS is higher in weeks when the temperature is colder. I find SIDS may be associated with viral pneumonia and "other respiratory" causes of death, judging from the seasonal and age at death patterns of those causes and SIDS. Low birth-weight is a strong predictor of SIDS, but seasonal variation in SIDS is not primarily due to seasonal variation in birth-weight, nor to variation in proportions of births which are premature.

Subject Area

Demographics|Public health

Recommended Citation

Hereward, Mark Courtenay, "An investigation of the seasonality of sudden infant death syndrome in the United States" (1990). Dissertations available from ProQuest. AAI9026573.