Aim To test whether alcohol is a risk factor for sudden infant death syndrome (SIDS).
Design and setting US epidemiological study using computerized death certificates, linked birth and infant death dataset, and Fatality Analysis Reporting System.
Participants All SIDS cases (n = 129 090) and other infant deaths (n = 295 151) from 1973–2006; all persons involved in late-night alcohol-related crashes (n = 135 946) from 1994–2008.
Measurements Three measures were used: the expected number of deaths on New Year versus the observed number (expected values were determined using a locally weighted scatterplot smoothing polynomial), the average number of weekend deaths versus the average number of weekday deaths, and the SIDS death rate for children of alcohol-consuming versus non-alcohol-consuming mothers.
Findings These measures indicate that the largest spikes in alcohol consumption and in SIDS (33%) occur on New Year, alcohol consumption and SIDS increase significantly on weekends, and children of alcohol-consuming mothers are much more likely to die from SIDS than are children of non-alcohol-consuming mothers.
Conclusions Alcohol consumption appears to be a risk factor for sudden infant death syndrome, although it is unclear whether alcohol is an independent risk factor, a risk factor only in conjunction with other known risk factors (like co-sleeping), or a proxy for other risk factors associated with occasions when alcohol consumption increases (like smoking). Our findings suggest that caretakers and authorities should be informed that alcohol impairs parental capacity and might be a risk factor for sudden infant death syndrome; in addition, future research should further explore possible connections between sudden infant death syndrome and alcohol.