Background Asphyxiation is the second leading cause of suicides in the United States (US). Asphyxiation can result from methods including smothering, choking, hanging, and chemicals. A better understanding of the distribution of asphyxia suicide decedent and incident characteristics may help identify strategies that can be used to reduce deaths from asphyxia-related suicides. The purpose of this study is to describe the distribution of asphyxiation suicides, which has not been previously investigated.

Methods This study used 2005–2014 National Violent Death Reporting System data. Asphyxiation types and means were identified through searching for key words in coroner/medical examiner narratives, law enforcement narratives, and causes of death. To calculate asphyxiation suicide rates, US population data were obtained from the Centres for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research.

Results From 2005–2014, there were 25 270 asphyxiation suicides. Most decedents were male (79.9%) and white, non-Hispanic (76.8%). Asphyxiation suicide rates increased by 46.6% from 2.9 per 1 00 000 in 2005 to 4.3 per 1 00 000 in 2014. Most asphyxiation suicides involved hanging (90.7%, n=22,931), 1691 involved smothering, 1228 involved strangulation, and 968 involved chemicals or gasses. The distribution of type of asphyxiation suicide varied by demographic subgroup. The five most common means of hanging suicides were power or extension cord (n=1,832), bedding (n=872), animal rope (e.g., n=578), clothing (n=455), and belt. Among the 968 suicides involving chemicals or gasses, the most frequently used gasses were helium (n=778), nitrogen (n=49), bromine (n=26), nitrous oxide (n=26), and propane (n=26).

Conclusions Asphyxiation suicides are completed using a variety of means. Means restriction is unlikely to be successful in reducing asphyxiation suicides, as commonly available objects are used in many of these suicides. Instead, efforts to reduce asphyxiation suicides should focus on mental health services, which potentially reduces deaths not only from asphyxiations suicides, but from all suicides.