Birth cohort analysis of deaths by suicide

Analysing deaths by suicide according to the period in which people were born can provide additional insights to that obtained by examining suicide rates by period of death (see Deaths by suicide over time).

A ‘birth cohort’ is a group of people born within the same defined period. People in a birth cohort age together over time and experience the same events and changes in technology or cultural norms at the same age.

This birth cohort analysis relates deaths by suicide to period of birth (birth cohort) and age at death. It examines how suicide rates change within birth cohorts as they age and how they vary between birth cohorts when compared at the same age.

Data sources and methods

This analysis is based on data from the AIHW National Mortality Database, which holds records for deaths in Australia from 1964.

Suicide rates by age at death (5-year age groups; ages 10–14 years and older) were calculated for each birth cohort. Birth cohorts can be defined in terms of any range of birth dates for which data are available; the cohorts presented here are those born in each 5-year period from 1954–58 through to 2004–08. The earliest birth cohort, those born in 1954–58, can be followed for over 60 years. For more information on data sources and methods, see Suicide in Australia: Trends and analysis 1964 to 2018.

How do suicide rates change among birth cohorts?

The interactive data visualisation shows how suicide rates have changed as people in each birth cohort have aged—with each line representing a birth cohort. By comparing the earlier birth cohorts with those born more recently, see how the age groups most at risk change.

Trends in suicide rates for birth cohorts from 1954–1958 to 2004–2008, by age at death, sex and mechanism, Australia.

The line graph shows age-specific rates of suicide for 5-year birth cohorts from 1954–1958 to 2004–2008 by age at death from 15–19 to 60–64 for males by all mechanisms. Users can also choose to view suicide rates by sex, mechanism and age at death. The highest suicide rate was in males born 1969–1973 who died aged 25–29, followed by males in this cohort who died aged 20–24.

In the earlier male birth cohorts (born 1954–58 to 1974–78) peaks in suicide rates for each subsequent birth cohort tended to be higher and occur at successively younger ages of death—with peaks tending to coincide with deaths occurring in the 1990s (period of death). For more information, see Suicide deaths over time. Suicide rates in these cohorts then tended to decline as they aged.

For example, peak suicide rates in males born in:

  • 1954–58 occurred at age 40–44 (29.4 deaths per 100,000 cohort members)
  • 1959–63 occurred at age 35–39 (31.0)
  • 1964–68 occurred at age 30–34 (34.0)
  • 1969–73 occurred at age 25–29 (36.9)
  • 1974–78 occurred at age 20–24 (33.4).

For the majority of the male cohorts born in the later years, from1974–78 onwards, suicide rates were still rising at the end of the available data; the oldest people in these cohorts were aged 42–46 years in 2018.

Suicide rates in female cohorts were much lower than those of male cohorts and for the earlier born cohorts tended to increase as they aged.

  • For example, the highest suicide rates in female cohorts were in those born in 1964–68 and 1969–73—the same cohorts that had the highest rates in males. However, peaks in suicide rates for these female cohorts tended to occur at older ages (9.7 and 9.5 at age 50–54 and 45–49, respectively) than in male cohorts (which peaked in early adulthood and then declined).

How do suicide rates vary between birth cohorts when compared at the same age?

The interactive data visualisation shows how suicide rates have changed for people of the same age, but born at different times—each line representing the same age group. By following the suicide rate of a specific age group, see how suicide rates have changed for people born between 1954 and 2008.

Trends in suicide rates at age of death across birth cohorts from 1954–1958 to 2004–2008, by sex and mechanism, Australia.

The line graph shows age-specific suicide rates for ages of death from 10–14 to 60–64, by 5-year birth cohorts from 1954–1958 to 2004–2008 by all mechanisms for females. Users can also choose to view suicide rates by sex, mechanism and for selected age-ranges at death. The rates of suicide among young females aged 15–19 at death showed the greatest change between the earliest and latest born cohorts for which data are available, almost doubling from 3.6 per 100,000 population in the 1954–1958 cohort to 6.4 in the 1999–2003 cohort, with some fluctuation in between these cohorts.

In females, the suicide rate at age 15–19 for those born most recently (1999–2003) was 1.8 times higher than the earliest cohort born in 1954–58. This pattern was not observed in males of the same age.

  • For females born in 1999–2003, the suicide rate reached 6.4 deaths per 100,000 cohort members at age 15–19—considerably higher than females born in 1954–58 (3.6 deaths per 100,000 cohort members).

Suicide rates at age 45–49 have increased with each successive birth cohort in both males (from 24.1 in those born in 1954–58 to 29.5 deaths per 100,000 cohort members in those born in 1969–73) and females (from 6.7 to 9.5 deaths per 100,000 cohort members in the same cohorts).

Suicide rates across male cohorts compared at the same age show no clear pattern. Rates at younger ages of death (15–19 and 20–24) tended to be higher for those born prior to 1979–83 than in those born in more recent cohorts (1984–1988 onwards).

  • For males born in 1984–88 the suicide rate at age 20–24 was almost half that of the cohort born in 1969–73 (18.0 deaths per 100,000 cohort members compared with 35.1).
  • Rates of suicide at age 15–19 for males born in 1974–78 were 1.8 times higher than those with the lowest rate born in 1954–58 (18.0 deaths per 100,000 cohort members and 10.0, respectively). Rates at age 15–19 were 12.3 deaths per 100,000 cohort members in the most recent male birth cohort for which data are available (1999–2003).

Trends in methods of suicide by birth cohort and age at death

Understanding the methods used for suicide can play an important role in suicide prevention. These data are provided to inform discussion around restriction of access to means as a policy intervention for the prevention of suicide.

Please consider your need to read the following information. If this material raises concerns for you or if you need immediate assistance, please contact a crisis support service, available free of charge, 24 hours a day, 7 days a week.

Please consider the Mindframe guidelines if reporting on these statistics.

The classification system used to code causes of deaths data, ICD-10, uses the term ‘mechanism’ to refer to the external cause of death. Throughout Suicide & self-harm monitoring ‘mechanism’ has been used in data visualisations, while the term ‘method’ has been used in the accompanying text.

The interactive data visualisations show which methods underlie changes in suicide rates as people in each birth cohort have aged (top visualisation)—and underlie changes in suicide rates for people of the same age, but born at different times (second visualisation).

Rates of suicide by hanging (ICD-10 X70):

  • tended to increase for both male and female birth cohorts as the cohort aged (top visualisation).
  • tended to increase in most age groups with each successive birth cohort in females; the pattern in males was less consistent (second visualisation). For example:
    • rates of suicide by hanging at ages 15–19 increased for each successive female birth cohort from a low of 0.1 per 100,000 cohort members in those born in the earliest cohort (1954–58) to a high of 4.9 in those born in the most recent cohort (1999–2003).
    • in the 2 most recently born female cohorts for which there are data available at ages 15–19 (born in 1994–98 and 1999–2003), rates of suicide by hanging were as high or higher than, rates at almost any other age in all other female cohorts.
    • for males, rates of suicide by hanging at ages 15–19 do not show the same pattern as females; rates in male cohorts increased up until those born in 1979–1983 and have since remained at about the same level (9.5 deaths per 100,000 cohort members for the latest birth cohort, born 1999–2003).

Rates of suicide by use of firearms (ICD-10 X72–X75) for both males and females peaked at younger ages (15–19 or 20–24) in all birth cohorts and then declined as cohorts aged (top visualisation). Suicide rates by this method tended to be lower for each successive birth cohort at all ages for which there are data available.

  • Each more recently born male cohort (born 1969–73 to 1989–93) had successively lower suicide rates by use of firearms at age 20–24 (7.3, 3.6, 1.5, 1.0 and 0.8 deaths per 100,000 cohort members).
  • A similar pattern was seen for female cohorts; however, rates were low.

Rates of suicide due to exposure to poisons excluding gas (ICD-10 X60–X66, X68–X69) in female cohorts were similar to that of male cohorts throughout the period 1964 to 2018 (0–3.6 deaths per 100,000 cohort members compared with 0–4.3, respectively)—unlike that of other suicide methods (top visualisation). Rates of suicide by this method were still rising for most male and female cohorts at the end of the available data.

Reference

Australian Institute of Health and Welfare. Henley G & Harrison JE 2020. Suicide in Australia: Trends and analysis–1964 to 2018. Injury research and statistics series no. 132. Cat. no. INJCAT 212. Canberra: AIHW.