Mednotes

L4 Public Health Epidemiology of suicide

Properties2
tagspublichealth, lecture
aliasesL4 Public Health Epidemiology of suicide

17 min read

Overview

This lecture covers the epidemiology of suicide using a public health framework: definitions and classification of suicide-related terms, descriptive epidemiology by person, place and time (both globally and in Aotearoa New Zealand), risk and protective factors (including specific factors relevant to Māori), population and individual approaches to prevention (particularly means restriction and responsible media reporting), and local advice and support services. The material follows the Public Health Model cycle: defining and measuring the problem, describing causes and consequences, developing and evaluating interventions, and disseminating effective policy and practice, fed by ongoing monitoring and evaluation.

Definitions and Classification

  • External Cause of Injury is classified primarily by underlying intent and mechanism, splitting into:
    • Unintentional: falls; road traffic (motor vehicle, pedestrian, motorcycle); drowning
    • Intentional: self-harm (e.g. via handgun); assault (e.g. via sharp object); collective violence (e.g. via bodily force)
  • Suicide: when someone has intentionally taken their own life.
  • Suicidal behaviour: behaviours that may occur as a result of suicidal distress, e.g. suspected self-injury (self-harm), suicidal distress, attempted suicide, and suicide.
  • Suicidal ideation: thoughts about taking action to end one’s life, including identifying a method, having a plan, or having an intent to act.
  • Deliberate self-harm: any type of self-injurious behaviour, including suicide attempts and non-suicidal self-injury.
  • Source: Ministry of Health. 2019. Every Life Matters. He Tapu te Oranga o ia tangata: Suicide Prevention Strategy 2019-2029; Turecki & Brent, Lancet 2016.

Global Epidemiology

WHO fact sheet (17 June 2021) key facts:

  • More than 700,000 (703,000) people die by suicide every year.
  • A prior suicide attempt is the single most important risk factor for suicide in the general population.
  • Suicide is the fourth leading cause of death among 15-29 year olds.
  • 77% of global suicides occur in low- and middle-income countries.
  • Ingestion of pesticide, hanging and firearms are among the most common methods globally.

Other global data:

  • National prevalence pattern across 20 countries (Turecki & Brent 2016): in every country, suicidal ideation was the most prevalent, suicide attempts next, and suicide deaths the least prevalent. USA and New Zealand had the highest ideation prevalence; Nigeria and Israel among the lowest. [slide values not precisely legible at this resolution, pattern read qualitatively]
  • Age-standardised suicide mortality map, 2016 (Global Burden of Disease Self-Harm Collaborators, BMJ 2019): highest rates (>=40/100,000) in Greenland; high rates in Russia and parts of Eastern Europe/Central Asia; lower rates across North and South America, Western Europe and Australia. [read at band level only, not precise country values]
  • Leading global causes of death by age group, 2012 (Injuries and Violence: The Facts 2014): suicide is the second leading cause of death for ages 15-29 (242,903 deaths, behind road traffic injuries) and the fifth leading cause for ages 30-49 (243,971 deaths), illustrating that injuries are a leading killer of youth. [slide title partly obscured by an inset image]
  • Two main sources of NZ suicide statistics:
    • Chief Coroner: publishes provisional annual statistics around August each year; figures are provisional because they cover suspected (not yet legally confirmed) self-inflicted deaths, since a coroner must rule a death self-inflicted before it can be legally described as suicide.
    • Ministry of Health: publishes the most current confirmed figures, always several years after the death because the coronial investigation for each death can take time.
  • Financial year to 30 June 2022: 538 people died by suspected suicide, rate 10.2 per 100,000; this was statistically significantly lower than the average rate over the preceding 13 financial years, and the third consecutive year of year-on-year reduction.
  • Long-term NZ trend, 1948-2018 (NZ Mortality Collection, confirmed suicides, age-standardised): rate around 10/100,000 in the late 1940s, dipping to about 8-9 in the 1950s-60s, fluctuating around 9-11 through the 1970s, rising through the 1980s to a peak of roughly 15 in the mid-to-late 1990s, then declining gradually with fluctuation to around 11-12 by 2018.

Several of the New Zealand trend graphs below (age, sex, ethnicity, deprivation, 2009-2021) are read from the slides as approximate visual trends only; the transcript does not give exact yearly values.

Suicide in Aotearoa New Zealand: Person (Age, Sex, Ethnicity, Deprivation)

Rates 2009-2021, age-standardised to the WHO standard population (confirmed + suspected suicides):

  • Age: the 15-24 band is consistently the highest, fluctuating roughly 15-23 with peaks around 2012 and 2019. The 25-44 and 45-64 bands sit in a similar mid-range (roughly 13-20). The 65+ band is lower and flatter (roughly 8-11). The 0-14 band stays near 0-1 throughout.
  • Sex: male rates are consistently much higher than female rates, fluctuating roughly 16-19 (dipping to about 16 around 2013) versus roughly 5-7 for females, consistent with the risk-factor finding that men are 3-4 times more likely to die by suicide.
  • Ethnicity: Māori have the highest rate throughout, rising from about 13 in 2009 to a peak of roughly 21 around 2019. Pacific and Other groups sit in the middle (roughly 10-14), tracking close to each other. Asian is the lowest throughout (roughly 4-6).
  • Deprivation (quintile 1 = least deprived to quintile 5 = most deprived): quintiles 4 and 5 tend to sit highest overall (roughly 12-16). Quintile 1 is generally lowest and most variable (dipping to about 6 around 2012, rising to about 9-10 later). The quintiles overlap and cross considerably rather than forming a strict gradient at every time point.

Cause-of-death context in young people, 2013-17 combined (Child and Youth Mortality Review Committee, 14th data report):

  • Ages 15-19 (n=661 deaths): suicide 36.2% (largest single cause), unintentional injury 35.7% (transport 26.0%, drowning 3.8%, poisoning 1.8%, other 4.1%), other medical 9.7%, neoplasms 9.7%, assault 1.4%.
  • Ages 20-24 (n=886 deaths): suicide 34.1%, unintentional injury 35.8% (transport 24.6%, drowning 4.3%, poisoning 1.9%, other 5.0%), other medical 10.6%, neoplasms 7.4%, assault 2.8%.

Risk and Protective Factors

General risk factors for suicide:

  • Previous suicide attempt; having experienced suicidal distress, thoughts or behaviours
  • Bereavement: losing a loved one or peer to suicide
  • Age: young people have the highest suicide rate in New Zealand
  • Gender: men are 3-4 times more likely to die by suicide (New Zealand and globally)
  • Sexuality: non-heterosexual people are at higher risk
  • Gender identity: people who do not identify with the sex they were assigned at birth are at higher risk
  • Ethnicity: Māori are more likely to die by suicide than non-Māori in New Zealand
  • Family and childhood experiences: poverty, deprivation, physical and/or sexual abuse, alcohol abuse, loss of significant family members
  • Mental illness (including depression, anxiety) and substance abuse
  • Hopelessness; exposure to media reporting/depictions of suicide
  • Relationship breakdown; loss of status or influence; loneliness; unemployment

Ministry of Health (2019) risk and protective factors:

  • Risk: bereavement by suicide; access to means of suicide; sense of isolation; history of mental illness, addiction or problematic substance abuse; previous suicide attempts; experience of trauma; exposure to bullying
  • Protective: good whānau and family relationships; access to secure housing; stable employment; community support and connectedness; secure cultural identity; ability to deal with life’s difficulties; access to support and help

Risk factors particularly relevant to Māori (Gluckman 2017, Youth Suicide in New Zealand): being colonised; being marginalised; being alienated from whānau and culture; being abused; being unwell; being deprived.

Indigenous and marginalised-group context: the lecture illustrates this pattern with examples including an Indigenous suicide crisis among Inuit communities in Canada’s Arctic (linked to a historical epidemic of abuse) and the elevated risk faced by transgender people. Honouring Te Tiriti o Waitangi: Māori suicide prevention research is moving away from a purely clinical approach toward approaches that build on cultural strengths and privilege indigenous values, worldviews, traditional knowledge and self-determination, with research increasingly led by and for Māori communities (Lawson-Te Aho 2017).

Suicide Prevention: Population Approaches

WHO population approaches to suicide prevention:

  1. Limit access to the means of suicide
  2. Interact with the media for responsible reporting of suicide
  3. Foster socio-emotional life skills in adolescents
  4. Early identify, assess, manage and follow up anyone affected by suicidal behaviours

Individual approaches: access to healthcare and support (mental health, chronic debilitating illness, caregivers). On the slide, individual approaches are visually de-emphasised relative to population approaches, with an arrow suggesting individual approaches feed into or are secondary to them. [the exact intended relationship is not stated on the slide]

Evidence for limiting access to means:

  • Grafton Bridge, Auckland: became a well-known suicide site after opening in 1910; steel barriers installed in 1937 reduced this; barriers were removed in 1996 and suicides resumed; new perspex canopies installed in 2003 were followed by zero deaths at the site over the next six years. [a further caption line is cut off in the source image]
  • Lawyers Head, Dunedin: after John Wilson Drive (the only access road) was closed in August 2006 for pipe construction, there were fewer suicide attempts at the site and no fatalities up to the time of the 2008 report, though attempts still occurred.
  • Sri Lanka pesticide bans (Knipe, Gunnell & Eddleston 2017): suicide incidence was low and flat (under 10/100,000) from 1880 to about 1950, rose steeply from the 1950s to a peak of roughly 80/100,000 around 1980-1995, then declined with fluctuation to roughly 15-20/100,000 by 2015, coinciding with a sequence of hazardous pesticide bans (1984: parathion, methylparathion; 1995: all remaining WHO Class I pesticides including methamidophos and monocrotophos; 1998: endosulfan; 2008: dimethoate, fenthion, paraquat). This was achieved through transparent, open, consistent, predictable and inclusive stakeholder engagement with industry from 1983 onward.
  • Other examples: gun control; limits on medication package size (e.g. paracetamol limited to 100 tablets); limits on prescription dispensing (which can be made daily); limits on sales of hazardous pesticides (e.g. Sri Lanka, Republic of South Korea).

Contagion and Media Reporting

  • Suicide contagion and clusters are well documented, especially among young people, and may spread through family, geographic or online communities, and through media messaging (news media and film).
  • Systematic review/meta-analysis evidence (BMJ 2020): suicide rates increased by 13% on average following media reports of a celebrity’s death by suicide, with a larger effect for subsequent suicides using the same method as the celebrity. General (non-celebrity) reporting was not clearly associated with increased suicide, though associations for certain types of reporting could not be excluded. The best available population-level intervention is guidelines for responsible reporting, more widely implemented and promoted, especially for celebrity deaths.
  • Coroners Act 2006, section 71 (Media guidelines for Reporting Suicide, Ministry of Health, 2021): when publishing information about a death that is, or is reasonably suspected to be, self-inflicted in New Zealand (or on a NZ-registered plane or ship):
    • The method or suspected method causing death cannot be published.
    • No detail suggesting the method or suspected method can be published (e.g. the place of death).
    • The death cannot be described as a suicide unless a coroner has certified suicide as the cause; it can be described as a “suspected suicide”.
  • CDC guidance (“avoid misinformation and offer hope”), instead of / do:
    • Instead of a big or sensationalistic headline or prominent placement, inform the audience without sensationalising and minimise prominence.
    • Instead of photos/videos of the location or method, grieving family, or funerals, use a school/work/family photo and include hotline or crisis line information.
    • Instead of “epidemic” or “skyrocketing”, use CDC data and neutral words like “rise” or “higher”.
    • Instead of describing a suicide as “inexplicable” or “without warning”, note that most (not all) people who die by suicide show warning signs, and include warning-signs guidance.
    • Instead of quoting a suicide note directly, describe it as being reviewed by the medical examiner.
    • Instead of investigating and reporting like a crime, report suicide as a public health issue.
    • Instead of quoting police or first responders on causes, seek advice from suicide prevention experts.
    • Instead of “successful”, “unsuccessful” or “failed attempt”, use “died by suicide” or “completed”.

Advice and Support

  • Healthline: 0800 611 116
  • Student Health and Counselling Services: 0800 479 821
  • General Practitioner
  • Emergency Psychiatric Services: 0800 467 846 (ask for EPS)

Self-test

  1. Define suicide, suicidal behaviour, suicidal ideation, and deliberate self-harm as used in this lecture.
  2. Using the External Cause of Injury classification, distinguish intentional from unintentional injury, giving two examples of each.
  3. What are the stages of the public health model cycle for suicide research and action?
  4. List the WHO’s five key global facts on suicide (2021 fact sheet).
  5. What pattern is seen across countries in the relative prevalence of suicidal ideation, suicide attempts and suicide deaths?
  6. Why are Chief Coroner suicide statistics described as provisional, and why are Ministry of Health figures published several years after each death?
  7. Describe the trend in New Zealand’s age-standardised suicide rate from 1948 to 2018.
  8. Distinguish how suicide mortality in Aotearoa New Zealand varies by age band, sex, ethnicity, and deprivation quintile (2009-2021).
  9. List at least eight general risk factors for suicide described in the lecture.
  10. Distinguish risk factors from protective factors for suicide, giving three examples of each from the Ministry of Health list.
  11. What six risk factors are identified as particularly relevant to Māori suicide risk, and what shift in research approach is described as needed to address them?
  12. List the WHO’s four population-level approaches to suicide prevention.
  13. Describe the evidence from Grafton Bridge and Sri Lanka’s pesticide bans that means restriction reduces suicide.
  14. Give two other examples of population-level means restriction mentioned in the lecture, besides Grafton Bridge and pesticide bans.
  15. Explain the evidence for suicide contagion via media reporting of celebrity deaths, and what is recommended as the best population-level response.
  16. Under Coroners Act 2006 s.71, what three restrictions apply to publishing information about a death that is or may be self-inflicted?
  17. A student journalist wants to report on a recent death that may be a suicide. Using the CDC guidance, what should they avoid and what should they do instead regarding headline language and description of the death?
  18. List the four advice and support services and their contact details given at the end of the lecture.
  19. Explain how the public health model cycle is reflected in the progression of content across this lecture, from definitions through to advice and support.

Answers

Graph View

Backlinks