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Mortality and Morbidity: Cardiovascular disease: 20th century trends
While death rates have fallen, the prevalence of cardiovascular disease has increased, with the proportion of people living with cardiovascular disease rising from 8% to 21% between 1977-78 and 1995.4 These rates of death and illness are associated with changes in behavioural factors and medical interventions. More about trends in causes of death during the 20th century can be found in Australian Social Trends 2001, Mortality in the 20th century.
DEATH RATES(a) FOR CARDIOVASCULAR DISEASE
(a) Age-standardised rate per 100,000 persons.
Source: AIHW Mortality Database.
Trends in death rates
There were three main changes in the pattern of deaths from cardiovascular disease between the beginning and end of the 20th century. First, male and female cardiovascular death rates are notably lower than they were at the beginning of the century for all age groups except the very oldest (80 years and over). Second, the decline in cardiovascular death rates across the 20th century was greater for younger age groups than for older age groups. For example, in 1907 the death rate for both girls and boys aged 5-9 years was more than 10 times larger than in 2000. Third, while the likelihood of dying from cardiovascular disease varied for males and females across age groups in 1907, the risk of dying was substantially higher for males than females at almost all ages in 2000. The death rates for men aged 25-79 years were around two to three times higher than for women in 2000.
AGE-SPECIFIC DEATH RATES(a) FOR CARDIOVASCULAR DISEASE
(a) Deaths per 100,000 people of the same sex and age group.
Source: AIHW Mortality Database.
Types of cardiovascular disease
The two leading causes of death from cardiovascular disease are ischaemic heart disease and cerebrovascular disease (stroke). Over the last three decades, ischaemic heart disease has been the leading cause of cardiovascular death for men and women. In 2000, it accounted for 59% of men's deaths and 48% of women's deaths from cardiovascular disease. This was despite a rapid decline in ischaemic heart disease death rates over the last three decades. Between 1968 and 2000, the death rate for ischaemic heart disease fell from 498 to 150 deaths per 100,000 for men, and from 250 to 84 deaths per 100,000 for women.
Stroke was the second most common cause of cardiovascular death since 1968, accounting for 21% of men's and 28% of women's deaths from cardiovascular disease in 2000. Throughout most of the 20th century, women were more likely to die from stroke than men. This pattern was reversed by 1968. Between 1968 and 2000, the male death rate fell from 184 to 54 deaths per 100,000, while the female rate fell from 168 to 48 deaths per 100,000. This represents a fall of 71% for both men and women over the period.
DEATH RATES(a) FOR SELECTED TYPES OF CARDIOVASCULAR DISEASE
Source: AIHW Mortality Database.
While the death rate from cardiovascular disease has declined, its prevalence in the population has increased, rising from 8% (1.1 million) in 1977-78 to 17% (2.2 million) in 1989-90 and to 21% (2.8 million) in 1995. This is partly associated with improvements in medical interventions, which have increased the survival rate among people living with cardiovascular disease. Improved techniques for diagnosing cardiovascular disease and better public information have increased the prevention and early detection of cardiovascular disease. The introduction of specialist ambulance services and better public knowledge of rescue-emergency management techniques have enhanced the immediate treatment of cardiovascular disease. Moreover, with the establishment of coronary care units and developments in surgery and drugs, the in-hospital care of patients has greatly improved.8
The health and economic costs of cardiovascular disease are greater than any other disease. In 1993-94, it accounted for $3.7 billion or 12% of total health costs.9 Burden of disease is a concept that has been developed as an indicator of population health, and refers to the impact of injury, disability and premature death on 'healthy life'. It is measured using the disability adjusted life year (DALY) concept. One DALY is equivalent to one year lost of 'healthy life', and summed together, DALYs can be used to represent the differing burden of various illnesses.9 In 1996, cardiovascular disease accounted for 22% of all disease burden in Australia.
In addition, studies on the burden of disease have assessed the relative importance of risk factors in illness, injury and premature death. The leading risk factors to which burden of disease was attributable in 1996 were tobacco smoking (10%), physical inactivity (7%), high blood pressure (5%), obesity (4%) and a lack of fruit and vegetables (3%).10 All of these risk factors are thought to influence the prevalence of cardiovascular disease.
(b) Kilograms consumed on average per person per year.
(c) Data for margarine and total (fat content) were not available for the three year period ending 30 June 1959.
(d) Average 3 year period ended 30 June.
(e) Includes fruit products, jams, conserves, dried fruit and processed fruit.
(f) Litres consumed on average per person per year.
Source: Apparent Consumption of Foodstuffs, Australia, 1997-98 and 1998-99 (ABS cat. no. 4306.0).
Changes in behaviour and lifestyle are associated with the changing rates of death and illness due to cardiovascular disease over the 20th century. Factors such as diet, alcohol and tobacco intake and levels of physical activity all influence body weight, blood pressure levels and blood cholesterol levels, which increase the risk of developing cardiovascular disease.9
The consumption of large amounts of fats has been associated with high cholesterol levels and obesity (where physical activity levels are low), which in turn increase the risk of dying from cardiovascular disease. Both the overall consumption of fats (particularly butter and whole milk) and of red meat (a source of saturated fat) have fallen since the late 1960s. In contrast, fresh fruit and vegetable consumption, which reduces the risk of cardiovascular disease, has increased in the second half of the 20th century.
Although low levels of alcohol consumption can protect against cardiovascular disease, excessive consumption is associated with conditions such as hypertension and obesity, which are linked to an increased risk of cardiovascular disease.4 Between 1939 and 1979, alcohol consumption rose and then fell steadily until the late 1990s.
Smoking was responsible for 13% of cardiovascular deaths in 1996, and increases the risk of heart attack and stroke three times in hypertensive individuals.9 The proportion of the adult population smoking declined from 37% in 1977 to 24% in 1995. This has helped to reduce rates of cardiovascular disease, particularly amongst men. However, there has been a recent trend towards more people, especially females, smoking in younger age groups, which may influence rates of cardiovascular disease in the future.11
Contrary to the popular image of Australians as active and sports-oriented, the last 15 years have seen notable increases in the proportion of overweight people. The proportion of overweight or obese women aged 25-64 years living in capital cities has increased from 27% in 1980 to 43% in 1995. For men the proportion increased from 48% to 63%.9 People who are physically inactive and who are obese are at a greater risk of developing cardiovascular disease than others.9 Lack of physical activity may be one factor behind the continuing high rates of illness from cardiovascular disease.
CURRENT SMOKERS AGED 18 YEARS AND OVER
Source: ABS 1977 Alcohol and Tobacco Consumption Patterns Survey; ABS 1989-90 National Health Survey; ABS 1995 National Health Survey.
1 Australian Institute of Health and Welfare (AIHW) 2000, First Report on National Health Priority Areas 1996, AIHW cat. no. PHE1, AIHW, Canberra.
2 d'Espaignet, E. T. 1993, Trends in Australian Mortality - Diseases of the Circulatory System: 1950-1991, Australian Government Publishing Service, Canberra.
3 Australian Bureau of Statistics 1995, National Nutrition Survey: Nutrient intakes and physical measurements, cat. no. 4805.0, ABS, Canberra.
4 Australian Bureau of Statistics 1995, National Health Survey: Cardiovascular and Related Conditions, cat. no. 4372.0, ABS, Canberra; and Australian Bureau of Statistics 1979, Australian Health Survey, 1977-78: Chronic Conditions, cat. no. 4314.0, ABS, Canberra.
5 Australian Institute of Health and Welfare, (AIHW) 2001, Heart, Stroke and Vascular Diseases: Australian Facts 2001, AIHW cat. no. CVD14, AIHW, Canberra.
6 Australian Bureau of Statistics 2001, Year Book, Australia 2001, cat. no. 1301.0, ABS, Canberra.
7 Australian Bureau of Statistics 2001, The Health and Welfare of Australia's Aboriginal and Torres Strait Islander Peoples, cat. no. 4704.0, ABS, Canberra.
8 Hugo, G. 1986, Australia's Changing Population, Oxford University Press, Melbourne.
9 Australian Institute of Health and Welfare (AIHW) 2000, Australia's Health 2000, AIHW cat. no. 19, AIHW, Canberra.
10 Australian Bureau of Statistics 2001, Health - Chronic Diseases and Risk Factors, <URL:http://www.abs.gov.au/ausstats> (accessed 23 November 2001).
11 Hill, D., White, V. and Letcher, T. 1999, 'Tobacco use among Australian secondary students in 1996', Australian and New Zealand Journal of Public Health, vol. 23, no. 3, pp. 252–259.