OBJECTIVE. Accidental suffocation and strangulation in bed, a subgroup of sudden, unexpected infant deaths, is a leading mechanism of injury-related infant deaths. We explored trends and characteristics of these potentially preventable deaths.
METHODS. In this descriptive study, we analyzed US infant mortality data from 1984 through 2004. To explore trends in accidental suffocation and strangulation in bed and other sudden, unexpected infant deaths, we calculated cause-specific infant mortality rates and estimated proportionate mortality. Sudden, unexpected infant death was defined as a combination of all deaths attributed to accidental suffocation and strangulation in bed, sudden infant death syndrome, and unknown causes. Finally, we examined factors that were reported as contributing to these accidental suffocation and strangulation in bed deaths.
RESULTS. Between 1984 and 2004, infant mortality rates attributed to accidental suffocation and strangulation in bed increased from 2.8 to 12.5 deaths per 100000 live births. These rates remained relatively stagnant between 1984 and 1992 and increased between 1992 and 2004; the most dramatic increase occurred between 1996 and 2004 (14% average annual increase). In contrast, total sudden, unexpected infant death rates remained stagnant between 1996 and 2004, whereas the proportion of deaths attributed to sudden infant death syndrome declined and to unknown cause increased. Black male infants <4 months of age were disproportionately affected by accidental suffocation and strangulation in bed. Beds, cribs, and couches were reported as places where deaths attributed to accidental suffocation and strangulation in bed occurred.
CONCLUSIONS. Infant mortality rates attributable to accidental suffocation and strangulation in bed have quadrupled since 1984. The reason for this increase is unknown. Prevention efforts should target those at highest risk and focus on helping parents and caregivers provide safer sleep environments.
January 28, 2009
From: Bradford D. Gessner, MD, MPH
Director, Maternal-Child Health Epidemiology Unit
Section of WOmens, Childrens, and Family Health
Alaska Division of Public Health
Suite 424
3601 C Street
Anchorage, Alaska 99524
Tel. 907-269-3446
Email. Brad.Gessner@alaska.gov
To: Editors
Pediatrics
Dear Editors,
Shapiro-Mendoza et al. report an increase in rates of infant mortality from accidental suffocation and strangulation (1) based on analysis of data from the National Center for Health Statistics. As the authors likely know, data from NCHS are provided by State Bureaus of Vital Statistics, which in turn must interpret causes of death recorded on death certificates. While NCHS data may be adequate for reporting overall infant mortality and for broad categories of causal mechanisms (congenital anomalies, infections, sudden unexpected infant death) they usually are inappropriate for looking at specific mechanisms such as accidental suffocation and strangulation. Data recorded on death certificates are affected by, among other things, the training of the recorder, diagnostic standards, funding for State Medical Examiners’ offices, existence of and adherence to requirements for autopsies, standardization of and use of death scene investigations by first responders, existence and composition of mortality review committees, and other issues. For example, we reported years ago an outbreak of infant viral myocarditis/pneumonitis mortality that resulted from misinterpretation of pathology specimens (2); at the time, the database used by the authors (CDC WONDER) indicated spuriously that Alaska had the highest infant myocarditis mortality rates in the nation by several-fold. Others, including the authors themselves (3), have demonstrated changes in classification of causes of infant deaths. The trends reported in the current study (1) most likely also derive from shifts in cause of death classification, the last few years notwithstanding.
While it is less work to analyze a pre-existing database, it may also provide uninterpretable results. In this case, if the US Centers for Disease Control and Prevention wants to evaluate the contribution to infant mortality of accidental suffocation and strangulation, they should consider actually reviewing medical records and autopsy reports. Furthermore, the Editors of Pediatrics should scrutinize carefully results and claims based on cause-specific analysis of vital records data. Readers unfamiliar with the nuances of such data may interpret the results Shapiro -Mendoza’s study as actually documenting an increase in suffocation and strangulation deaths. At best these results form the basis for generating a hypothesis that requires testing with a more robust study.
Sincerely,
Bradford D. Gessner, MD Alaska Division of Public Health
1. Shapiro-Mendoza CK, Kimball M, Tomashek KM, Anderson RN, Blanding S. US Infant mortality trends attributable to accidental suffocation and strangulation in bed from 1984 through 2004: are rates increasing? Pediatrics 2009;123:533-539. 2. Centers for Disease Control and Prevention. Misclassification of infant deaths—Alaska, 1990-1991. Morb Mort Wkly Rep 1992; 41:584-5,591. 3. Shapiro-Mendoza CK, Tomashek KM, Anderson RN, Wingo J. Recent national trends in sudden, unexpected infant deaths: more evidence supporting a change in classification or reporting. Am J Epidemiol. 2006;163:762–769.
Conflict of Interest:
None declared