Changes over time in means of suicide in Canada: an analysis of mortality data from 1981 to 2018

BACKGROUND:Ongoing surveillance of the means of suicide is necessary for effective prevention. We examined how mortality rates owing to different means of suicide changed in Canada from 1981 to 2018.METHODS:We obtained data from 1981 to 2018 on suicide deaths of individuals aged 10 years and older, from the Canadian Vital Statistics Death Database. We used joinpoint regression analysis to examine changes over time in the suicide mortality rate for the 3 most common means of suicide.RESULTS:The age-standardized suicide mortality rate declined in earlier decades for both sexes, but did not significantly change in recent decades for either sex. The age-standardized rate of suicide by suffocation increased from 1993 for females (2.1% per year) and from 1996 for males (0.4% per year). The age-standardized rate of suicide by poisoning decreased for females (2.2% per year) and males (2.1% per year) from 1981 to 2018. The age-standardized rate of suicide by firearm decreased from 1981 to 2008 (7.4% per year) but did not significantly change there-after for females; for males, it decreased 2.1% per year from 1981 to 1993 and 5.7% per year from 1993 to 2007, but did not significantly change thereafter.INTERPRETATION:For both sexes, the rate of suicide by poisoning is decreasing, the rate of suicide by suffocation is increasing, and the rate of suicide by firearm has not significantly changed in the last decade. Given the high proportion of suicide deaths by suffocation, its increasing rate and the difficulty of restricting the means of suffocation, other approaches to suicide prevention are needed.

The overall suicide mortality rate in Canada is lower than it was a few decades ago, but continued declines have been absent in recent years and the impact of suicide remains high.^1,2 Suicide was the ninth leading cause of death in 2018.³ More than three-quarters of suicide deaths in Canada are a result of suffocation, poisoning and firearms.^4–6 Suffocation is the predominant suicide method in most countries.⁴ However, the prevalence of different means of suicide can vary over time because of changes in the accessibility of certain means.⁷ Evidence suggests that the relative frequency of different means of suicide has changed in Canada, but those studies have not included data from more recent years.^8,9 Ongoing surveillance of the means of suicide and understanding changes over time are essential for designing and implementing prevention programs.¹⁰It is especially important to consider sex and age in suicide surveillance, because of differences across these sociodemographic characteristics. For instance, females are more likely to self-report thoughts of suicide and to be admitted to hospital owing to self-inflicted injuries,^5,11 while suicide mortality rates are about 3 times higher among males than females in Canada.^2,3,6 Higher suicide mortality rates for males have been observed in almost all countries,¹ and have been attributed, in part, to more lethal means of suicide (e.g., firearms).^5,6,12 Suicide-related behaviour also varies across the lifespan, with the suicide mortality rate tending to be high in middle-aged adults and males older than 80 years, but hospital admissions owing to self-inflicted injuries tending to occur during adolescence (particularly among females).^2,3,5,6,13Canadian data from 2000 to 2009 indicated that suicide by suffocation was more prevalent among individuals aged 15–39 years, while suicide by firearm was more prevalent among individuals aged 60 years and older.⁶ Canadian data for 2001 to 2011 suggested that rates of suicide by firearm and poisoning declined for males aged 15 years and older, but were unchanged among females during this period.⁹ Less is known about whether the means used by age and sex groups have fluctuated over longer periods and in more recent years. We sought to document the means of suicide deaths in Canada in 2018 (the most recent data available at the time of writing) and investigate how the use of different means has changed for males and females and across age groups since 1981.