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Suicide among young Australians, 1964-1993: an interstate comparison of metropolitan and rural trends

Michael J Dudley, Norman J Kelk, Tony M Florio and John P Howard
Med J Aust 1998; 169 (2): 77-80.
Published online: 20 July 1998

Suicide among young Australians, 1964-1993: an interstate comparison of metropolitan and rural trends

Michael J Dudley, Norman J Kelk, Tony M Florio, John P Howard and Brent G H Waters

MJA 1998; 169: 77-80
See also Rosenman

 

Abstract - Introduction - Methods - Results - Discussion - Acknowledgements - References - Authors' details
- - ©MJA1998


 

Abstract

Objectives: (i) To compare suicide rates in 15-24 year old men and women; and (ii) for 15-24 year old men, to investigate differences in suicide rates between metropolitan and rural areas, and changes in method-specific suicide rates and, in particular, firearm and hanging suicide rates in rural and metropolitan areas.
Design:
Retrospective analysis of Australian Bureau of Statistics (ABS) suicide data (1964-1993).
Setting:
All Australian States.
Subjects:
Young women and men aged 15-24 years who died by suicide.
Results: Male youth suicide rates rose substantially over the 30 years in all Australian States, whereas female rates did not increase. Increases in suicide rates in young men in small rural towns consistently exceeded those in metropolitan areas in all Australian States. Metropolitan rates in 1964 were higher than those in small rural towns, but by 1993 the position was reversed. Medium-sized cities were the only areas where there was no consistent interstate trend. Differences were noted in suicide base rates in different States. High car exhaust suicide rates were noted in Western Australia, and high firearm suicide rates in Tasmania and Queensland. The ratio of firearm suicide rates in small rural areas to those in metropolitan areas rose in all mainland States, but the same ratio for hanging suicide rates changed little.
Conclusions:
All Australian States reflect national suicide trends in relation to sex and residential area. In some States, particular suicide methods predominate. A decreasing trend in overall firearm suicide rates in young men in all States from 1984 to 1993 conceals substantial increases in firearm suicide rates in small rural areas in all mainland States over the 30-year period. This, together with the marked rate ratio difference in firearm suicides between metropolitan and small rural areas, suggests that particular risk factors for suicide are operating in small rural areas. The fact that hanging rate ratios changed little suggests that more general factors in male youth suicide are also operating in all areas. A better understanding of similarities and differences in health risks faced by metropolitan and rural youth is required.  

Introduction

Suicide rates for 15-24 year old Australian men have trebled since the early 1960s. However, these rate increases have not been uniform. In metropolitan areas they have doubled, but they have increased as much as 12-fold in towns with fewer than 4000 people. The rates for suicide with a firearm in 15-24 year old men have declined overall, and in metropolitan areas since the late 1980s, but they have continued to rise in rural areas. Rates of suicide by hanging have risen in all locations.1

We aimed to answer questions about whether these national suicide trends are replicated at the State level. We wanted to know whether the trends for the larger States dominate the national picture, or whether the same fundamental trends are occurring in all States. Interstate analysis is also important, because health, education and welfare services are often organised and funded at a State level. Differences among the States have long been part of the Australian culture, and firearms legislation, in particular, is at present a State prerogative.

In this article, we report suicide rates in young men and women (aged 15-24 years) in all Australian States and Territories, as well as suicide rates in young men by method of suicide, and by residential area, in all States, for 1964 to 1993.  

Methods

Our methods are described in more detail elsewhere.1 Data on suicides and corresponding population data for subjects aged 15-24 years were sought from the Australian Bureau of Statistics (ABS) for the years 1964-1993. These data were de-identified, and an undertaking was given not to attempt to identify the subjects or to contact their families. Data concerning usual area of residence were available for all but 219 of 8537 people who had died by suicide. Subjects' usual place of residence was classified as:
  • metropolitan areas of capital cities of each State;
  • cities with populations >100 000;
  • cities with populations >25 000;
  • towns with populations >4000; or
  • towns with populations <400.

These cut-offs, chosen after consulting social geographical sources,2,3 approximate Australian urban groupings in order of size. Definitions of "metropolitan" and "rural" also follow guidelines given in these sources. Rates throughout are expressed as numbers of suicides per 100 000 of the at-risk population. Data were aggregated in 5-year epochs to enable longer-term trends to be discerned.  

Results

 

Sex-specific suicide rates

Suicide rates in 15-24 year old men rose substantially over the past 30 years in all Australian States and Territories, but rates in women of the same age did not (Figure 1).

We will consider suicide rates in 15-24 year old men only in the remainder of the article.  

Method-specific suicide rates

Considering the whole 30-year period, for 15-24 year old men, a clear trend exists, both nationally and for individual States, of a reduction in firearm suicide rates in the past 10-15 years, and of an increase in hanging suicide rates over the whole period at a substantially greater rate than the increase by all other methods. Car exhaust suicide rates also increased at a greater rate than the overall increase, especially in Western Australia, but to a lesser extent than suicide by hanging. Suicides by poisoning did not increase proportionally in any States or nationally. Hanging is now the most common method of youth suicide in most States, exceeding firearms as a means of suicide in all States except Queensland and Tasmania. In the most recent epoch, firearm suicide rates were highest in Tasmania and Queensland (Figure 2).  

Residence-specific suicide rates

In all States, suicide rates in 15-24 year old men have increased substantially in metropolitan areas, but the greatest increases have been recorded for towns with a population under 4000. In 1964 in four States (New South Wales, Victoria, Queensland, Western Australia), metropolitan suicide rates exceeded those of small rural areas, but by 1993 the position was reversed (Figure 3).

New South Wales
Suicide rates in 15-24 year old men rose consistently in all residential categories except cities with over 25 000 people. Sydney's rates rose least (1.6-fold), smaller towns (population, <4000) rose the most (9.9-fold), and Newcastle- Wollongong (2.7-fold) and towns with populations over 4000 (3.8-fold) were intermediate.

Victoria
Suicide rates in 15-24 year old men rose in all residential areas. Melbourne's rates began from a low baseline, and in 1964 rate differences between Melbourne and smaller towns (population, <4000) were less marked than in NSW. Melbourne's rates rose least (4.2-fold), smaller towns with fewer than 4000 people the most (34.5-fold), and Geelong (5.7-fold) and larger towns (population, >4000) (5.5-fold) were intermediate.

Queensland
Suicide rates in 15-24 year old men in Brisbane trebled, and rates for the Gold Coast and Sunshine Coast, areas with a high population growth, which both now exceed 100 000 people, peaked in the mid 1970s, but then fell. Rates in cities (population, >25 000 and larger towns (population >4000) increased 1.7- and 1.9-fold, respectively, but in smaller towns (population, <4000) the increase was 31.6-fold.

South Australia
Differences in suicide rates in 15-24 year old men between metropolitan and small rural areas were less marked in States with lower populations. Adelaide's suicide rate for young men rose 2.7-fold, and in towns with populations under 4000 it rose 5.5-fold. Rates in larger towns (population, >4000) increased 1.8-fold. High rates in cities with populations >25 000 were based on small numbers.

Western Australia
Suicide rates in 15-24 year old men in Perth rose 2.5-fold and rates in smaller towns (population, <4000) rose 7.0-fold. Rates in larger towns (population, >4000) fluctuated, rising 3.2-fold overall.

Tasmania
Tasmania's suicide rates in 15-24 year old men have been consistently high. While Hobart's rates have more than doubled, rates in smaller towns (population, <4000) have risen 3.6-fold. Trends elsewhere were inconsistent, although high rates have been recorded.  

Firearm and hanging suicide rates for metropolitan and small rural areas

Suicide with firearms or by hanging, the most common methods, account for between a half and two-thirds of suicides in 15-24 year old men in each State, so these have been analysed by place of residence. In all States the ratio of the firearms suicide rate in small rural areas to the firearms suicide rate in metropolitan areas rose substantially over the 30-year period. In contrast, this ratio for suicide rates by hanging remained much the same or rose minimally over the same period. Thus, the national trend for a reduction in firearm suicide rates conceals a continuing rise in firearm suicide rates in rural areas in all States. These increases were especially pronounced in Victoria and Queensland (41.5- and 36.7-fold respectively), while Tasmania's rates remained high throughout the period (Figure 4).  

Discussion

National youth suicide trends according to sex of the subject are reflected in the rates of all the individual States: suicides in 15-24 year old men rose substantially, whereas those in 15-24 year old women did not change in the past 30 years. The disproportionate increase in suicide rates in young men in small rural areas nationally is also occurring consistently in all Australian States.

Certain data limitations should be noted.

  • Coroners often must exercise subjective judgements in determining verdicts, which may lead to possible systematic differences in rates between different States and over time;

  • Errors may also arise from unstandardised methods of recording suicides, especially earlier in the study period;1

  • Population data may fluctuate in minor ways with changing residential area boundaries, notably with some towns being absorbed into larger cities; and

  • The data do not allow inferences about particular local geographical areas (see for comparison National Injury Surveillance Unit data4).

However, it is unlikely that changing coronial verdicts account for the magnitude or generality of the changes we noted.

Cantor and Coory5 found that Queensland's provincial cities and rural towns of modest size had negligible rate increases compared with metropolitan and major urban areas from 1986 to 1991. They questioned whether there was a rural suicide problem in Queensland. Our study confirms their observations for Queensland cities with populations over 25 000, but notes a massive rate increase in towns with fewer than 4000 people, with substantial numbers supporting this finding. Further, the Queensland picture does not appear to be atypical.

There are differences in suicide base rates in the various States. Whether Melbourne's low base rate in 1964 is coincidental, or a result of Victorian coroners showing less willingness to reach a verdict of suicide, requires further investigation. Tasmania's relative isolation, demographically stable population, and easy firearm access may explain its consistently high suicide rates.

Suicide methods differ somewhat between States. The high rates for car exhaust suicides in Western Australia may reflect its relative isolation and this method's cultural acceptability. Carbon monoxide sensors, exhaust modifications and changes to catalytic converters may be effective prevention measures.6

High firearm suicide rates among 15-24 year old men in Tasmania and Queensland,7 rising metropolitan firearm suicide rates in those States, and rising rates in small towns (population, <4000) in all States, but especially Victoria and Queensland, probably relate to falling populations in small rural areas with stable or rising suicide numbers, the easy availability of firearms, and the more liberal firearm legislation in Tasmania and Queensland.

Applying methods to prevent car exhaust suicide and reducing the availability of guns may reduce suicide rates by these two methods, and possibly total suicide rates.8

While rates for suicide by various methods may differ in different States, residential area trends for firearm and hanging suicides were pronounced in all States. A trend for overall firearm suicide rates to decrease in all States from 1984-1993 conceals substantial firearm rate increases in small rural areas in all mainland States over the 30-year period. Differences in rates between metropolitan and small rural areas, and the fact that the ratio of firearms suicide rates in small rural areas to those in metropolitan areas rose substantially in all mainland States, suggest that particular risk factors (directly and indirectly related to firearms) are operating in small rural areas. Restrictive legislation may differentially affect firearm suicides in metropolitan areas, where availability is lower.9 The rural economic downturn, the strain on small rural communities, and a major population exodus in all States from towns with fewer than 4000 people have meant added health burdens for those communities, with possibly specific risk factors.1 The fact that the equivalent ratio for hanging rates changed little suggests that more general factors are also operating across all areas in relation to suicide in young men.

Particular States have local issues which require specific attention, but the fact that all Australian States reflect the national trends in youth suicide in relation to sex and residential area supports a national approach to youth suicide prevention. Effective national approaches will depend in part on acquiring a better understanding of the similarities and differences in health risks faced by metropolitan and rural youth.1 

Acknowledgements

Thanks are due to Caroline Haski and Margaret Alcock for their painstaking work as research assistants, and to the NSW Institute of Psychiatry, which partly funded this study.  

References

  1. Dudley M, Kelk N, Waters B, et al. Suicide among young rural Australians 1964-1993: a comparison with metropolitan trends. Soc Psychiatry Psychiatr Epidemiol 1997; 32: 251-260.
  2. Department of Primary Industries and Energy and Department of Human Services and Health. Rural, remote and metropolitan areas classification, 1991 Census edition. Canberra: AGPS, 1994.
  3. Holmes J. In: Jeans D, editor. Space and society. Chapters 2 and 3. Sydney: Sydney University Press, 1988: 24-74.
  4. Moller J. An atlas of injury death in Australia 1990-1992. Adelaide: National Injury Surveillance Unit, 1995. Also available online: <www.nisu.flinders.edu.au/data/atlas/atlas.html>
  5. Cantor C, Coory M. Is there a rural suicide problem? Aust J Public Health 1993; 17: 382-384.
  6. Australian Institute for Suicide Research and Prevention. Access to means of suicide by young Australians; a background report to the Commonwealth Department of Health and Family Services Youth Suicide Prevention Advisory Group. Brisbane: Australian Institute for Suicide Research and Prevention, 1996.
  7. Cantor C, Lewin T. Firearms and suicide in Australia. Aust N Z J Psychiatry 1990; 24: 500-509.
  8. Cantor C, Baume P. Access to methods of suicide: what impact? Aust N Z J Psychiatry 1998; 32: 8-14.
  9. Cantor C, Slater P. The impact of firearm control legislation on suicide in Queensland: preliminary findings. Med J Aust 1995; 162: 583-585.

(Received 12 May 1997, accepted 17 Apr 1998)  


Authors' details

University of New South Wales, Sydney, NSW.
Michael J Dudley, MB BS, FRANZCP, Lecturer, School of Psychiatry.
Norman J Kelk, PhD, Social Worker, School of Community Medicine.

Prince of Wales Hospital, Sydney, NSW.
Tony M Florio, MPsych, Clinical Psychologist.

Macquarie University, Sydney, NSW.
John P Howard, PhD, Clinical Psychologist.

PO Box 474, Edgecliff, NSW.
Brent G H Waters, MD, FRANZCP, Psychiatrist.

Reprints will not be available from the authors.
Correspondence: Dr M J Dudley, Department of Child and Adolescent Psychiatry, Sydney Children's Hospital, Randwick, NSW 2031.
E-mail: m.dudleyATunsw.edu.au


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Received 16 November 2018, accepted 16 November 2018

  • Michael J Dudley
  • Norman J Kelk
  • Tony M Florio
  • John P Howard


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