Studying sudden and unexpected infant deaths in a time of changing death certification and investigation practices: evaluating sleep-related risk factors for infant death in New York City.

We describe an approach for quantifying and characterizing the extent to which sudden and unexpected infant deaths (SUIDs) result from unsafe sleep environments (e.g., prone position, bedsharing, soft bedding); and present data on sleep-related infant deaths in NYC. Using a combination of vital statistics and medical examiner data, including autopsy and death scene investigation findings, we analyzed any death due to accidental threat to breathing (ATB) (ICD-10 W75 & W84), and deaths of undetermined intent (UND) (Y10-Y34) between 2000 and 2003 in NYC for the presence of sleep-related factors (SRF). Homicide deaths were excluded as were SIDS, since in NYC SIDS is not a certification option if environmental factors were possibly contributors to the death. All 19 ATB and 69 (75%) UND had SRFs as per the OCME investigation. Black infants and infants born to teen mothers had higher SRF death rates for both ATB and UND deaths. Bedsharing was the most common SRF (53%-ATB; 72%-UND deaths); the majority of non-bedsharing infants were found in the prone position (60%-ATB; 78%-UND deaths). We found a high prevalence of SRFs among ATB and UND deaths. This is the first local study to illustrate the importance of knowing how SUIDs are certified in order to ascertain the prevalence of infant deaths with SRFs. Advancing the research requires clarity on the criteria used by local medical examiners to categorize SUIDs. This will help jurisdictions interpret their infant mortality statistics, which in turn will improve education and prevention efforts.