3311.4.55.001 - Demography, South Australia, 2002  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 05/05/2004   
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Special Article - Deaths of South Australian Baby Boomers


There were approximately 441,000 baby boomers (29% of the population) residing in South Australia at 30 June 2003. The ABS refers to baby boomers as those people born in the period 1946-1965 inclusive, and by the end of 2003 they were aged between 38 and 57 years inclusive. The social and economic impact this large group will have over the next few decades is of interest to policy makers and service providers. Principal areas of concern include the employment effects and the ability to support health and welfare expenditure as baby boomers age.

To assist and encourage informed decision-making on issues related to baby boomers, the publication South Australia's Baby Boomers: A Profile, 2003 (cat. no. 4149.4.55.001) was released in November 2003. This article extends that work, and provides further information on deaths and the causes of death of baby boomers and the cohort of persons born ten years prior to them.

The three birth cohorts considered in this article are:

  • later-born baby boomers - those people born in 1956-1965
  • earlier-born baby boomers - those people born in 1946-1955
  • people born in the ten years prior to the baby boomers, i.e. born in 1936-1945.

The article examines deaths registered in the period between 1982 and 2002 for each of these birth cohorts. Comparisons of death rates between age groups generally show that the likelihood of death increases as age increases, but they do not show if there are any generational effects. The lifetime circumstances and experiences of each of the baby boomer cohorts and the cohort born ten years earlier are different, and these differences potentially impact on their mortality. This article looks at the differences in mortality by comparing information about the birth cohorts when the cohorts' members were the same age.

NUMBER OF DEATHS

There were 11,987 deaths registered in 2002 of persons usually resident in South Australia. Of these deaths, 8% were baby boomers - 3% of the total deaths were later-born baby boomers and 5% were earlier-born baby boomers. Discussion of the number of deaths is used here to introduce the method of graphing data from the three birth cohorts. Once this concept is explained, age-specific death rates are introduced.

Graph 1 shows the number of deaths registered in each year from 1982 to 2002 for each of the three birth cohorts. For example, each point along the bold line shows the number of deaths of later-born baby boomers in a specific year. The left hand end of the line shows the number of deaths of the later-born baby boomers in the year they were aged 16 to 25 years (1982), then deaths in the following year (1983) when they were aged 17 to 26 years, and so on until the year 2002, when the later-born baby boomers were aged 36 to 45 years. The other lines on the graph represent deaths of the earlier-born baby boomers (for the years 1982 to 2002) and deaths of the cohort born in the ten years earlier (for the years 1982 to 2002).

The main purpose of this article is to compare the cohorts when they were the same age. Graph 1 shows the number of deaths in each cohort when the members of each cohort were aged between 36 and 45 years. For each cohort, these deaths were registered in different years: 2002 for the later-born baby boomer cohort, 1992 for the earlier-born cohort and 1982 for the cohort born in 1936-1945.

1. DEATHS, Persons
Graph 1 - Deaths of persons born in 1936-1945, 1946-1955 and 1956-1965
(a) Later-born baby boomers
(b) Earlier-born baby boomers


Graph 1 illustrates that there were more deaths of the later-born baby boomers than the earlier-born baby boomers as both cohorts aged from between 26 and 35 years to between 36 and 45 years. Over these ages, later-born baby boomers experienced 13% more deaths. Similarly, when looking at deaths between the ages of 36 and 45 years to between 46 and 55 years, there were 18% more deaths of the earlier-born baby boomers than the cohort born in 1936-1945. A similar pattern of cohorts having more deaths than earlier-born cohorts is evident for both sexes; however, there were more deaths of males than females for every age group.

One of the reasons for the difference in number of deaths is the population size of each cohort. There were on average 6% more later-born baby boomers than earlier-born baby boomers as both cohorts aged from between 26 and 35 years to between 36 and 45 years. When looking at deaths between the ages of 36 and 45 years to between 46 and 55 years, there were 38% more earlier-born baby boomers than the cohort born in 1936-1945.


AGE-SPECIFIC DEATH RATES

To remove the effects of different population sizes, age-specific death rates (ASDRs) are examined. These are presented in graphs 2 and 3 for each sex. In graph 2, the left hand end of the bold line indicates that there were 1.2 deaths of males born in 1956-1965 when they were aged between 16 and 25 years (in 1982) per 1,000 of the male estimated resident population of the same age at 30 June 1982.

Graphs 2 and 3 are presented with the same scale and show that death rates for males were higher than those for females for every age group. From 1982-2002, male ASDRs were on average 2.3 times that of female ASDRs for the later-born baby boomer cohort and 1.7 times that of female ASDRs for the other two cohorts.

For each sex, a comparison of birth cohorts suggests that the earlier-born baby boomer cohort (the thin dark line) had lower death rates than both the later-born baby boomer cohort and the cohort born prior to them in 1936-1945. ASDRs of the later-born baby boomers were slightly higher (on average 7% for males and 4% for females) than the earlier-born baby boomers as the cohorts aged from between 26 and 35 years to between 36 and 45 years. ASDRs of the earlier-born baby boomers were 14% lower for males and 17% lower for females than the cohort born in 1936-1945 as the cohorts aged from between 36 and 45 years to between 46 and 55 years.


2. AGE-SPECIFIC DEATH RATES, Males
3. AGE-SPECIFIC DEATH RATES, Females
Graph 2 - Age-specific death rates of males born in 1936-1945, 1946-1955 and 1956-1965
Graph 3 - Age-specific death rates of females born in 1936-1945, 1946-1955 and 1956-1965
(a) Deaths per 1,000 male population
(b) Later-born baby boomers
(c) Earlier-born baby boomers
(a) Deaths per 1,000 female population
(b) Later-born baby boomers
(c) Earlier-born baby boomers


In summary, the improvement in earlier-born baby boomers ASDRs over the cohort born ten years prior to them is consistent with overall improvements in life expectancy in South Australia and Australia in recent decades. This cohort had a larger population, and a higher number of deaths, but once adjustment is made for population size (by using ASDRs) this cohort experienced a lower death rate per thousand of the population.

It is interesting that this improvement in ASDRs is not observed in the later-born baby boomer cohort, which had slightly higher death rates than the earlier-born cohort when they were the same age. This is perhaps explained when we examine the differences between the cohorts in the causes of death.


CAUSES OF DEATH
In 2002, the leading underlying cause of death for both male and female baby boomers was malignant neoplasms (cancers) causing 273 male and 214 female deaths. Ischaemic heart diseases (76 male and 18 female deaths) and intentional self-harm (59 male and 13 female deaths) were also predominant underlying causes of death. Graphs 4 and 5 show the ASDRs for males and females for the most common cancers and other common causes of death for the baby boomer cohorts and the cohort born ten years earlier than them.

4. MAIN UNDERLYING CAUSES OF DEATH,
Males, 2002

Graph 4 - Age-specific death rates from the main underlying causes of death in 2002 of males born in 1936-1945, 1946-1955 and 1956-1965
(a) Later-born baby boomers
(b) Earlier-born baby boomers


5. MAIN UNDERLYING CAUSES OF DEATH,
Females, 2002

Graph 5 - Age-specific death rates from the main underlying causes of death in 2002 of females born in 1936-1945, 1946-1955 and 1956-1965
(a) Later-born baby boomers
(b) Earlier-born baby boomers


Malignant neoplasms (cancers)

Graphs 6 and 7 show the ASDRs for cancers for males and females. From 1982-2002, cancer ASDRs for male later-born baby boomers were 15% lower than those for females born in the same years and cancer ASDRs for male earlier-born baby boomers were 16% lower than those for females born in the same years. In contrast, cancer ASDRs for males born in 1936-1945 were 8% higher than those for females born in the same years.

Comparisons of cohorts show that cancer ASDRs are lower for later-born cohorts than earlier-born cohorts when they were the same age. Cancer ASDRs of the later-born baby boomers were lower (8% for males and 18% for females) than the earlier-born baby boomers as the cohorts aged from between 26 and 35 years to between 36 and 45 years. Similarly, cancer ASDRs of the earlier-born baby boomers were lower (11% for males and 16% for females) than the cohort born in 1936-1945 as the cohorts aged from between 36 and 45 years to between 46 and 55 years. The fall in death rates from cancer for the baby boomer cohorts is consistent with declines in cancer death rates for the South Australian population as a whole.


6. AGE-SPECIFIC CANCER DEATH RATES, Males
7. AGE-SPECIFIC CANCER DEATH RATES, Females
Graph 6 - Age-specific cancer death rates of males born in 1936-1945, 1946-1955 and 1956-1965
Graph 7 - Age-specific cancer death rates of females born in 1936-1945, 1946-1955 and 1956-1965
(a) Deaths per 100,000 male population
(b) Later-born baby boomers
(c) Earlier-born baby boomers
(a) Deaths per 100,000 female population
(b) Later-born baby boomers
(c) Earlier-born baby boomers


ASDRs for the male later-born baby boomers were on average 25% lower for cancers of the digestive organs and 3% higher for trachea, bronchus and lung cancers than the male earlier-born baby boomers as both cohorts aged from between 26 and 35 years to between 36 and 45 years. The corresponding rates for females were 14% lower for cancers of the digestive organs and 19% lower for trachea, bronchus and lung cancers. For female breast cancers, the rates were 3% higher.

ASDRs for the male earlier-born baby boomers were on average 8% lower for cancers of the digestive organs and 28% lower for trachea, bronchus and lung cancers than the cohort born in 1936-1945 as both cohorts aged from between 36 and 45 years to between 46 and 55 years. The corresponding rates for females were 27% lower for cancers of the digestive organs and 28% lower for trachea, bronchus and lung cancers. For female breast cancers, the rates were 14% lower.

Ischaemic heart diseases

Graphs 8 and 9 show the ASDRs for ischaemic heart diseases for males and females. These graphs, presented with the same scale, show that ASDRs for ischaemic heart diseases for males were higher than those for females for every age group, except for a few younger age groups when there were no deaths from these diseases. From 1982-2002, ischaemic heart disease ASDRs were on average 3.7 times greater for male later-born baby boomers than female later-born baby boomers, 5.3 times greater for male earlier-born baby boomers than female earlier-born baby boomers and 4.5 times greater for males born in 1936-1945 than females born in the same years.

For males, ASDRs for ischaemic heart diseases of the later-born baby boomers were 27% lower than the earlier-born baby boomers as both cohorts aged from between 26 and 35 years to between 36 and 45 years. For females, the number of deaths are too low to draw any conclusions between the ASDRs of later-born and earlier-born baby boomers. There were large improvements in ASDRs for ischaemic heart diseases between earlier-born baby boomers and the cohort born in 1936-1945; the rates were 38% lower for males and 40% lower for females as the cohorts aged from between 36 and 45 years to between 46 and 55 years.


8. AGE-SPECIFIC DEATH RATES OF ISCHAEMIC HEART DISEASES, Males
9. AGE-SPECIFIC DEATH RATES OF ISCHAEMIC HEART DISEASES, Females
Graph 8 - Age-specific death rates of ischaemic heart diseases of males born in 1936-1945, 1946-1955 and 1956-1965
Graph 9 - Age-specific death rates of ischaemic heart diseases of females born in 1936-1945, 1946-1955 and 1956-1965
(a) Deaths per 100,000 male population
(b) Later-born baby boomers
(c) Earlier-born baby boomers
(a) Deaths per 100,000 female population
(b) Later-born baby boomers
(c) Earlier-born baby boomers

Intentional self-harm (suicide)

In 2002, 41% of males of the later-born baby boomer cohort died from external causes (accidents, poisonings and violence) compared with 59% from diseases. External causes resulted in 75 of the 184 deaths of male later-born baby boomers in 2002. Intentional self-harm (suicide) was the major cause of these external deaths, accounting for 41% of external deaths or 17% of all deaths of this cohort. For females born in the same years, there were 24 deaths from external causes representing 21% of this cohort's 117 deaths in 2002. Suicides accounted for 7 of these deaths.

Graphs 10 and 11 show the ASDRs for intentional self-harm (suicide) for males and females for both baby boomer cohorts and the cohort born in 1936-1945. Suicide ASDRs were higher for males than for females for every age group. From 1982-2002, suicide ASDRs were an average 4.0 times greater for male later-born baby boomers than female later-born baby boomers, 3.5 times greater for male earlier-born baby boomers than female earlier-born baby boomers and 3.3 times greater for males born in 1936-1945 than females born in the same years.

In contrast to cancers and ischaemic heart diseases, comparisons of male cohorts show that suicide ASDRs are higher for later-born male cohorts than earlier-born male cohorts when they were the same age. For males, suicide ASDRs of the later-born baby boomers were 39% higher than the earlier-born baby boomers as both cohorts aged from between 26 and 35 years to between 36 and 45 years. Suicide ASDRs of the male earlier-born baby boomers were 18% higher than the male cohort born in 1936-1945 as the cohorts aged from between 36 and 45 years to between 46 and 55 years. For females, the comparative rates were 10% higher for later-born baby boomers compared with the earlier-born baby boomers and 3% lower for earlier-born baby boomers compared with the female cohort born in 1936-1945.


10. AGE-SPECIFIC SUICIDE DEATH RATES, Males
11. AGE-SPECIFIC SUICIDE DEATH RATES, Females
Graph 10 - Age-specific suicide death rates of males born in 1936-1945, 1946-1955 and 1956-1965
Graph 11 - Age-specific suicide death rates of females born in 1936-1945, 1946-1955 and 1956-1965
(a) Deaths per 100,000 male population
(b) Later-born baby boomers
(c) Earlier-born baby boomers
(a) Deaths per 100,000 female population
(b) Later-born baby boomers
(c) Earlier-born baby boomers


The rise in death rates from suicides for the baby boomer cohorts differs from the general decline in suicide death rates which has occurred for the South Australian population as a whole. As mentioned earlier in this article, males of later-born baby boomers had higher death rates than males of earlier-born baby boomers as both cohorts aged from between 26 and 35 years to between 36 and 45 years (refer graph 2). However, if suicide deaths are excluded from the data then both cohorts have similar death rates. Therefore, it is possible to conclude that the higher suicide rates in later-born baby boomers are a major contributor to the higher total death rates experienced by later-born baby boomers.


CONCLUSION

This analysis examined deaths registered between 1982 and 2002, for three different age cohorts. It showed that there have been improvements in the death rates between the cohort born ten years earlier and the earlier-born baby boomers, however this improvement has not carried through to the later-born baby boomers, who had slightly higher death rates than the earlier-born cohort when they were the same age. Male and female earlier-born baby boomers had the lowest ASDRs of the three age cohorts.

In terms of specific causes of death the death rates for the total South Australian population have decreased over the past decade, with improvements in the rates of death from cancers, ischaemic heart diseases and suicide. The analysis shows that both the later-born and earlier-born baby boomer cohorts experienced the same trend of lower death rates for cancers and ischaemic heart diseases as the cohort born ten-years earlier when they were the same age. However, death rates from suicide were higher for baby boomers than the cohort born ten-years earlier when they were the same age. Higher suicide rates in later-born baby boomers are a major contributor to the higher total death rates experienced by later-born baby boomers.


METHODOLOGY

Information on death registrations is supplied to the ABS by the South Australian Registrar of Births, Deaths and Marriages. There is usually an interval between the occurrence and registration of a death, and approximately 5% of deaths are not registered in the year in which they occur. Data presented in this article refer to deaths in the year of registration.

Death registration statements provide information on age at death and year of birth of the deceased. Data on year of birth are not available for deaths registered in 1982; therefore, for this analysis, age at death data were used to estimate baby boomers' years of birth. For example, a person who died in 2002 aged 56 years may have been born in either 1945 or 1946. The distinction is important in deciding if that person was a baby boomer or not. Results were checked by using 2002 data, when year of birth data were available. This analysis showed that the process of estimating year of birth lead to minimal differences (approximately 2%) for both baby boomer cohorts.


FURTHER INFORMATION

For further information about deaths of baby boomers, contact Susan Jones on (08) 8237 7465 or susan.jones@abs.gov.au. For information on South Australian baby boomers on other health topics, demography, cultural background, family structures, housing, education and community life, please see South Australia's Baby Boomers: A Profile, 2003 (cat. no. 4149.4.55.001).

For demography information about South Australians of all ages, please see Demography, SA, 2002 (cat. no. 3311.4.55.001)