eMJA - Under review: Australian suicide trends 1964-1997

Objective: To examine Australian suicide rates across the age span, contrasting these with those of other western nations and thereby comment on the appropriateness of prioritising youth for suicide prevention.

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Design and participants: ABS data was used to examine Australian suicide trends, 1964-1997, by age and sex. Australian age/sex suicide rates were then compared with those of 22 other western nations.

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Results: Australian suicide rates for 15-24 and 24-35 year old males rose from 1964-1997. Comparable rates for females showed no significant change. Suicide rates for a number of older age/sex groups declined and were continuing to decline at the end of the period. International comparisons found that whereas Australian youth suicide rates are relatively high this is not so for older ages. Australian suicide rates are higher than the nations of origin of the major European migrant groups, but similar to those of other new western nations - i.e. Canada, USA and New Zealand.

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Conclusions: Youth is the correct priority group but the priority age range should be extended to include 25-34 year olds. Also a comprehensive policy should not neglect the needs of other ages. Further epidemiological study of national and international data may reveal opportunities for suicide prevention from the perspectives of both service delivery and cultural change.

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It is well known that Australia has a high rate of suicide in males aged 15-24. The last Federal Labor Government, the former and current Federal Coalition Governments have instituted committees to address youth suicide rates. Beyond youth there have been only sporadic reports of suicide rates in other age groups ¹ including suggestions of high rates in the extreme elderly. ^{2, 1}

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This report presents suicide rates and trends across the lifespan placing them in context by comparison with comparable figures from the Western world. The national focus on youth to the relative exclusion of older ages is examined in the light of the data.

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Method

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Suicide and population data for Australia from 1964 to 1997 was obtained from the Australian Bureau of Statistics (ABS) and annual suicide rates were calculated. These were plotted by 10 year age groups and gender over time. The changes in rate over time was calculated and the significance of the changes determined by confidence intervals. Autocorrelation was applied to determine the significance in the overall trends.

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Annual potential years of life lost were calculated for ten year age sex groups for the most recent year 1997. The formula used to calculate this was adapted from ABS ³ in order to incorporate age groups. This formula is as follows:

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YPLL=D_x(75-A_x)C_x

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D_x = Total number of suicides for that particular age group.

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A_x = Average age of age group (i.e. the middle age was taken, so for the age group 15-24 the age was taken as 19.5)

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C_x = (N_xs x N)
N _s x N _x

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N_xs = number of persons in the particular age group in the standard population.

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N = number of persons aged 1-74 years in the 1997 population.

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N_s = number of persons aged 1-74 in the standard population.

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N_x = number of persons in the particular age group in the 1997 population.

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The Australian population at 30 June 1991 was chosen as the standard population, as suggested by ABS.

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International data were obtained from the World Health Organization (WHO) ^4-7 and Lester and Yang. ⁸ Mean suicide rates were calculated for 23 western countries (including Australia) averaged between 1990-1994, for 10 year age/sex groups. These 10 year age/sex rates were ranked in order for comparison of Australia with Western nations.

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Results

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Figures 1 through 8 show the suicide rates over time by gender and 10 year age groups, including all ages combined.

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1 Rates of suicide, combined ages by gender, Australia 1964-1997

2 Rates of suicide, aged 15-24 by gender, Australia 1964-1997

3 Rates of suicide, aged 25-34 by gender, Australia 1964-1997

4 Rates of suicide, aged 35-44 by gender, Australia 1964-1997

5 Rates of suicide, aged 45-54 by gender, Australia 1964-1997

6 Rates of suicide, aged 55-64 by gender, Australia 1964-1997

7 Rates of suicide, aged 65-74 by gender, Australia 1964-1997

8 Rates of suicide, aged 75+ by gender, Australia 1964-1997

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Change over time was examined by comparing the suicide rate in 1964-1966 with the suicide rate in 1995-1997. Confidence intervals ( P<0.05) were calculated to determine if the change was significant. Suicide rates for males of combined ages and those aged 15-24 and 25-34 increased significantly over time. The rise in the 25-34 year group from 1973-1997 was of similar magnitude to 15-24 year old males as illustrated in figures 2 and 3. Suicide rates for females for all ages combined and for each age group from 25-75+ and males in each age group 35-75+ showed declines, although, for males aged 35-44 and 75+ these declines were not statistically significant. There was no change in suicide rates for females aged 15-24.

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Significant autocorrelations ( P<0.01) were found for all male age groups and all ages combined. For females the trends for the 15-24 and 75+ age groups were non-significant, with trends for all other females age groups and all ages combined being significant.

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Years of potential life lost is shown in Table 1.

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When comparing Australia's age/sex suicide rates to those of 22 other Western countries, rankings for Australian males were: ages 15-24 years ranked 4th; 25-34 8th; 35-44 13th; 45-54 13th; 55-64 15th; 65-74 13th; and 75+ 15th. For Australian females rankings were: ages 15-24 ranked 8th; 25-34 14th; 35-44 16th; 45-54 17th; 55-64 14th; 65-74 16th; and 75+ 15th.

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[NB. This paragraph can be replaced by the sentence "The rank ordering of Australian suicide rates with 22 other western countries by 10 year age groups are shown in tables 2 and 3" with an insertion of the optional tables 2 and 3 as found in the appendix.]

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Discussion

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The priority accorded to youth suicide by successive governments is supported by the data. In the three decades when overall suicide rates were falling, the suicide rate of males 15-24 years more than doubled. Suggestions of a plateauing of this rate since 1989 is not supported by the latest 1997 figure, although it is premature to be conclusive. From a policy perspective the most important finding is that suicide rate increases since 1973 for 25-34 year males paralleled those of 15-24, with even less evidence of a recent plateau. Despite the shorter life expectancy remaining, the toll in potential years of life lost was greater for 25-34 year olds. These years are also the peak years for early parenthood and the impact on bereaved offspring would exceed that of the younger group. These findings suggest that youth suicide prevention priority initiatives should be extended to 15-34 years, if not further as the potential years of life lost is great up to 44 years.

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Females aged 15-24 showed no convincing rise. It has previously been noted that female 15-19 suicide rates 1960-1989 rose modestly while rates for 20-24 showed no overall change over that period. ⁹ However, much of the rise in 15-19 year females was in the early 1960s predating the male15-19 rise but coinciding with a general rise in females of all ages. Perhaps the most important observation regarding young females in the present study is that their suicide rates remained relatively static at a time when rates of most other female ages declined. This suggests that an unfavourable youth influence may have been offset by a favourable female gender influence - the implication being that young females may be vulnerable to similar youth suicide influences despite their suicide rates appearing static.

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Suicide rates in children under 15 years of age have not significantly altered over time although the small numbers involved do not lend confidence to rates. The recording of suicide in children under the age of 10 years is affected by different ABS criteria for determining suicide, whereby it is considered that children have a limited ability to form intent to suicide. Hence more explicit evidence of suicidal intent is required by ABS. ¹⁰ This usually requires a coroner to have explicitly stated that suicide was the cause of death. As most State and Territory Coroners’ Acts discourage if not prohibit such findings (in all ages) such explicit statements are unlikely. ¹⁰

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Beyond 35 in females and 45 years of age in males up to late life (75+ years) Australian suicide trends are striking. In both genders there have been major declines for most ages between 35 and 74 years and for much of the period the declining rates have been parallel for both genders, quite unlike the trends for 15-24 year olds. Mostly these rates continued downwards at the 1997 endpoint. It is inevitable that shortly these declining rates will level out and increase again - inevitable as by current trends a number of these age rates would reach zero in the early decades of the next century. In the early 1960s suicide rates, particularly in females, and those of older ages, rose in association with an epidemic of poisoning by barbiturates, subsequently to fall in the late 1960s, reaching rates in the early 1970s similar to prior to this epidemic. ^11-12 The causal factors determining the subsequent decline in rates of those between the ages of 35 to 74 are yet to be determined. It is possible that such determination might yield valuable clues as to the causes and potential prevention of suicide in youth.

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Compared with Western nations, Australian suicide rates for 15-24 year males ranked fourth of 23 western nations and eighth for young females. Australian rates for both genders between the ages of 35-74 years are not only declining but compared favourably (ranking in the middle of or below other Western nations). Although Australian suicide rates for those over 75 years were not declining they nevertheless again compare favourably from an international perspective. Whereas the Australian 15-24 male rate was just over half that of the highest placed nation, the corresponding ratio for males 75+ years was one sixth. For females these comparisons were even more marked. Ironically service provision to the Australian elderly is less developed than for many nations with higher suicide rates. Nevertheless, a comprehensive policy should not overlook the needs of those over 75 years, especially as in Australian males their suicide rates surpass all other age groups.

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The nations experiencing lower suicide rates include the western nations that have dominated early migration to Australia: i.e. Greece, Italy (except in the elderly), the United Kingdom and Ireland. The highest suicide rates occurred in mainland Western Europe (especially Hungary) and Scandanavia (especially Finland). Some of these nations, for example Denmark, have profiles radically different to Australia, with lower youth suicide rates but much higher rates in those over 35 years of age.

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Canada and to a lesser extent the USA and New Zealand are the nations with the most similar profiles to Australia. All four of these nations have common characteristics of European migration, short history outside their indigenous populations, geographical isolation, climatic extremes and more, ⁹ serving as potentially valuable nations to study shared characteristics that may fuel suicide.

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Studies have yet to provide explanations for these similarities and differences which have often been overlooked, largely as a consequence of the worldwide lack of epidemiological mental health data. While differences in prevalence of psychiatric disorders are potentially relevant, the magnitude of the different international rates suggest other factors operate. Hungary and Finland share common cultural origins and high suicide rates. It has been suggested that Finland’s high young male rates relate to the cultural expectation that men should be tough and resilient ¹³ - a suggestion that might equally be levelled at Australia, New Zealand, the USA and Canada. This suggests that cultural change, in addition to service provision, should also be considered as potentially relevant to suicide prevention.

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Acknowledgments

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The study was funded by Griffith University and The Department of Public Health through their co-funding of the Australian Institute for Suicide Research and Prevention.

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We thank the Australian Bureau of Statistics for providing information on suicide and population numbers.

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References

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1. Snowdon J. Suicide rates and methods in different age groups: Australian data and perceptions. Int J Geriatric Psychiatry 1997; 12: 253-258.

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2. Hassan R, Carr J. Changing patterns of suicide in Australia. Aust N Z J Psychiatry 1989; 23: 226-234.

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3. Australian Bureau of Statistics. Causes of Death, Australia, 1996.

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4. WHO. World Health Statistics Annual 1992. Geneva: WHO, 1993.

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5. WHO. World Health Statistics Annual 1993. Geneva: WHO, 1994.

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6. WHO. World Health Statistics Annual 1994. Geneva: WHO, 1995.

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7. WHO. World Health Statistics Annual 1995. Geneva: WHO, 1996.

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8. Lester D, Yang B. Suicide and Homicide in the Twentieth century: Changes Over Time. Commack, NY: Nova Science, 1998.

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9. Cantor CH, Leenaars AA, Lester D, et al. Suicide trends in eight predominantly English-speaking countries 1960-1989. Soc Psychiatry Psychiatric Epidem 1996; 31: 364-373.

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10. Cantor CH, Neulinger K, Roth J, Spinks D. The Epidemiology of Suicide and Attempted Suicide Among Young Australians: A Report to the National Health and Medical Research Council: Australian Institute for Suicide Research and Prevention, in press.

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11. Oliver G, Hetzel BS. An analysis of recent trends in suicide rates in Australia. Int J Epidem 1973; 2: 91-101.

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12. Whitlock FA. Suicide in Brisbane, 1956-1973: The drug-death epidemic. Med J Aust 1975; 1: 737-743.

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13. Retterstol N. Suicide in the Nordic countries. Psychopathology 1992; 25: 254-265.

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1: Annual potential years of life lost for 1997, by age group and gender

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Age	Number of suicides		Rate of suicide (per 100 000)		Years of potential life lost
Group	Male	Female	Male	Female	Male	Female
10-14	8	7	1.2	1.1	509	443
15-24	417	93	30.6	7.1	25407	5710
25-34	540	115	37.5	8.0	25707	5456
35-44	431	122	30.2	8.5	15045	4197
45-54	294	96	24.3	8.2	6339	2031
55-64	179	56	22.6	7.2	2732	862
65-74	146	47	23.7	6.9	760	257
75+	131	41	36.0	7.0	n.a.	n.a.

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OPTIONAL TABLES

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2: Rank ordering of mean male suicide rates for 23 Western countries by 10 year age groups, 1990-1994.

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(for latest available years)

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Rank	15-24	25-34	35-44	45-54	55-64	65-74	75+
1^st	Finland 41.4	Finland 60.7	Hungary 82.0	Hungary 95.1	Hungary 84.6	Hungary 92.5	Hungary 183.0
2nd	New Zealand 39.0	Hungary 54.4	Finland 67.8	Finland 64.1	Finland 57.3	Austria 61.1	Austria 118.0
3rd	Switzerland 25.8	Switzerland 32.7	France 40.1	Denmark 47.5	Austria 46.7	Belgium 50.4	France 103.0
4th	Australia 25.7	New Zealand 32.0	Denmark 38.1	Austria 41.5	Denmark 42.6	Switzerland 47.4	Belgium 98.6
5th	Canada 25.2	France 32.0	Austria 37.2	France 40.1	Switzerland 41.9	France 47.1	Switzerland 89.8
6th	Norway 24.9	Belgium 30.5	Belgium 35.6	Switzerland 39.8	Belgium 38.9	Denmark 46.4	Germany 86.1
7th	Austria 24.3	Austria 30.3	Switzerland 33.0	Belgium 36.2	France 38.1	Finland 45.9	Denmark 74.9
8th	USA 21.9	Australia 29.0	Sweden 29.3	Sweden 31.9	Germany 32.2	Germany 35.9	Finland 71.9
9th	Hungary 20.1	Canada 29.0	Canada 27.3	Germany 31.1	Sweden 30.7	Sweden 33.7	Portugal 59.1
10th	Scotland 19.0	Ireland 27.1	Norway 26.9	Norway 28.8	Norway 28.8	USA 30.9	USA 55.4
11th	Ireland 18.3	Denmark 26.4	Scotland 26.2	Canada 25.6	Ireland 25.9	Norway 30.7	Sweden 51.9
12th	Northern Ireland 17.6	Norway 26.1	Germany 26.0	Scotland 24.2	USA 25.0	Portugal 30.1	Spain 47.8
13th	Belgium 15.7	Scotland 26.1	Australia 25.2	Australia 24.2	Canada 24.2	Australia 24.4	Italy 44.3
14th	France 15.3	USA 24.6	New Zealand 23.9	New Zealand 24.2	New Zealand 23.2	Spain 23.2	Netherlands 35.4
15th	Germany14.0	Sweden 23.9	USA 23.5	USA 23.1	Australia 22.9	Italy 22.9	Australia 32.8
16th	Sweden 13.4	Northern Ireland 22.4	Ireland 22.9	Ireland 19.6	Portugal 21.5	Canada 22.1	Norway 31.8
17th	Denmark13.0	Germany 21.3	Netherlands 17.7	Netherlands 16.7	Netherlands 18.6	New Zealand 21.2	New Zealand 29.8
18th	England & Wales 11.1	England & Wales 16.3	England & Wales 17.4	England & Wales 16.2	Scotland 18.1	Netherlands 19.7	Canada 28.9
19th	Netherlands 9.3	Netherlands 15.9	Northern Ireland 15.5	Northern Ireland 15.1	Northern Ireland 17.4	Ireland 18.3	England & Wales 17.1
20th	Spain 7.0	Portugal 13.2	Portugal 11.8	Portugal 14.6	Spain 17.4	Scotland 14.3	Scotland 16.0
21st	Italy 6.1	Spain 10.6	Italy 10.6	Italy 12.6	Italy 17.1	Northern Ireland 12.8	Greece 15.8
22nd	Portugal 5.8	Italy 10.3	Spain 9.4	Spain 11.9	England & Wales 12.8	England & Wales 11.9	Ireland 13.8
23rd	Greece 4.0	Greece 5.6	Greece 5.9	Greece 6.7	Greece 7.8	Greece 10.1	Northern Ireland 13.3

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3: Rank ordering of mean female suicide rates for 23 Western countries by 10 year age groups, 1990-1994

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(for latest available years)

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	15-24	25-34	35-44	45-54	55-64	65-74	75+
1st	Finland 7.5	Finland 12.0	Hungary 20.3	Hungary 26.5	Denmark 28.5	Hungary 37.6	Hungary 67.3
2nd	Austria 6.2	Belgium 11.8	Finland 17.4	Denmark 25.5	Hungary 28.0	Denmark 31.5	Denmark 30.2
3rd	Hungary 6.2	Hungary 11.6	Denmark 15.7	Finland 20.4	Belgium 17.9	Belgium 23.5	Austria 28.5
4th	New Zealand 6.2	Sweden 10.1	Belgium 14.5	Belgium 18.2	France 17.6	Switzerland 19.8	Germany 26.4
5th	Sweden 5.9	Switzerland 9.0	Switzerland 13.5	Austria 17.1	Finland 17.5	Austria 18.5	France 25.3
6th	Switzerland 5.8	France 9.0	France 13.0	Switzerland 16.7	Austria 17.4	France 17.9	Belgium 24.2
7th	Norway 5.5	Scotland 8.3	Austria 12.1	France 16.5	Switzerland 17.0	Germany 16.7	Switzerland 23.0
8th	Australia 5.1	Austria 8.0	Sweden 11.8	Sweden 15.0	Sweden 15.4	Sweden 13.5	Sweden 14.2
9th	Belgium 5.1	Denmark 7.7	Norway 9.8	Germany 12.1	Germany 12.9	Finland 13.3	Portugal 12.2
10th	Canada 4.9	New Zealand 7.3	Netherlands 9.6	Norway 11.5	Norway 12.0	Norway 12.4	Netherlands 12.1
11th	France 4.5	Netherlands 7.2	Canada 8.1	Netherlands 9.5	Netherlands 10.9	Netherlands 10.4	Spain 11.9
12th	USA 3.8	Norway 7.1	Germany 7.7	Northern Ireland 9.4	New Zealand 7.7	Spain 8.8	Finland 9.6
13th	Netherlands 3.7	Ireland 6.7	New Zealand 6.9	New Zealand 8.9	Ireland 7.7	Portugal 8.1	Italy 9.3
14th	Scotland 3.7	Australia 6.6	Scotland 6.8	Canada 8.1	Australia 6.9	Italy 8.0	Norway 9.2
15th	Germany 3.5	Canada 6.4	Northern Ireland 6.8	USA 7.3	USA 6.8	New Zealand 6.6	Australia 8.0
16th	Denmark 3.3	Germany 5.7	Australia 6.6	Scotland 7.2	Italy 6.8	Australia 6.6	Scotland 6.0
17th	Ireland 2.5	USA 5.3	USA 6.6	Australia 7.0	Scotland 6.7	Ireland 6.4	USA 6.0
18th	Northern Ireland 2.4	Northern Ireland 3.9	Ireland 4.8	Ireland 6.8	Canada 6.4	Scotland 6.4	England & Wales 5.9
19th	Portugal 2.2	Portugal 3.5	England & Wales 3.9	Portugal 5.0	Portugal 6.2	USA 6.2	Canada 4.7
20th	England & Wales 2.1	England & Wales 3.5	Italy 3.9	Italy 4.9	Spain 6.0	Canada 6.1	New Zealand 4.3
21st	Italy 1.8	Italy 2.9	Portugal 3.8	England & Wales 4.7	Northern Ireland 4.8	England & Wales 5.2	Greece 3.4
22nd	Spain 1.7	Spain 2.6	Spain 3.0	Spain 3.9	England & Wales 4.7	Northern Ireland 3.9	Ireland 3.0
23rd	Greece 0.7	Greece 1.4	Greece 1.3	Greece 2.3	Greece 2.4	Greece 2.8	Northern Ireland 2.5

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