4102.0 - Australian Social Trends, 2003  
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Contents >> Health >> Risk factors: Health risk factors among adults

Risk factors: Health risk factors among adults

Between 1989-90 and 2001, the proportion of physically inactive Australian adults declined and smoking rates decreased. However, the proportion of adults who were overweight or obese increased.

There are a range of risk factors associated with higher rates of illness or injury in the population. Such factors may be physiological (e.g. high blood pressure), they may relate to the environment (e.g. air pollution) or to lifestyle choices (e.g. smoking). Risk factors have been found to contribute substantially to disease and disability, and thus to reduced length of life and quality of life in Australia.1 However, many risk factors are modifiable. Their impact may often be reduced through action taken by individuals (e.g. quitting smoking or undertaking exercise). In turn, these actions may be influenced by government or community action (e.g. anti-smoking education).


Risk factors
Data in this article come from the ABS 1989-90, 1995 and 2001 National Health Surveys. Data collected in regard to smoking, physical activity and overweight/obesity are comparable across the three time periods. In this article, the data refer to adults aged 18 years and over.

To account for the different age structure of the population at each survey as well as between certain sub-populations (such as smokers/ non-smokers) all rates and proportions presented in this article have been age standardised. The standard population used was the 2001 National Health Survey benchmark population.

Current smokers refers to those adults who answered ‘yes’ when asked whether they currently smoked. It is not based on regularity of smoking.

Ex-smokers refers to those adults who were not current smokers but reported they had previously smoked regularly.

Never smoked refers to those adults who have never smoked regularly.

Levels of exercise were assessed as inactive, low, moderate or high based on the frequency, duration and intensity of deliberate exercise.

Deliberate exercise refers to exercise undertaken for recreation, sport or fitness during the two weeks prior to interview. Types of exercise covered in the survey were walking, moderate and vigorous exercise.

Physically inactive adults refers to adults who did no exercise or who exercised at a very low level in the two weeks prior to interview.

Overweight and obesity were measured using the body mass index (BMI). The BMI is calculated as weight (kg) divided by height (m) squared. A BMI of 25 or more indicates overweight, and 30 or more indicates obesity.3 BMI data presented in this article are based on self-reported height and weight estimates. Therefore, the figures presented are considered to be underestimates since studies have shown that respondents tend to overestimate height and underestimate weight.4

For more detail refer to National Health Survey: Summary of Results, 2001 (ABS cat. no. 4364.0).


This article focuses on three risk factors: smoking; physical inactivity; and overweight and obesity. While each of these is discussed individually, they interact with other risk factors, and are rarely the sole contributor to a disease.2 In 1996, the risk factor responsible for the greatest disease burden was tobacco smoking.1 That is, this factor had the greatest impact on reducing the quality and length of life of Australians. It was responsible for 12% of all healthy years lost due to early death or disability among males and 7% among females. Physical inactivity was responsible for 6% of the total disease burden for males and 8% for females, while overweight and obesity accounted for 4% for both males and females.1

BURDEN OF DISEASE FOR SELECTED RISK FACTORS - 1996
Graph - Burden of disease for selected risk factors - 1996

a) Disability adjusted life years. One DALY is a healthy year of life lost calculated by combining years lost due to early death and healthy years lost from disability.

Source: AIHW The Burden of Disease and Injury, 1999 (Cat. No. PHE 17. Canberra: AIHW).


Between 1989-90 and 2001, the proportion of Australian adults (aged 18 years and over) who smoked declined. At the same time, adults increased the amount of deliberate exercise they undertook. However, despite this rise in deliberate physical activity, the adult population, on average, became more overweight or obese.

Smoking
Worldwide, smoking is estimated to cause almost 5 million premature deaths each year.5 In Australia, it is estimated that around 19,000 people died as a result of smoking in 1998.6 Among other conditions, smoking is associated with increased risk of coronary heart disease, stroke, lung cancer, other types of cancer and various respiratory and cardiovascular diseases.2 In 2001, people aged 18 years and over who currently smoked were 2.0 times more likely to have bronchitis and were 1.7 times more likely to have emphysema compared with non-smokers. In relation to other conditions such as coronary heart disease, there was little difference between current smokers and people who had never smoked. However, current smokers combined with ex-smokers were 1.4 times more likely to have coronary heart disease and were 1.7 times more likely to have a malignant cancer than those who had never smoked. These higher disease rates - apparent once ex-smokers are included - suggest that certain health conditions may be associated not only with current smoking but with a history of smoking.

PROPORTION OF ADULTS WHO WERE CURRENT SMOKERS
Graph - Proportion of adults who were current smokers

Source: ABS 1989-90, 1995 and 2001 National Health Surveys.


In 2001, 24% of the adult population were current smokers. This followed an overall decrease in smoking among the adult population (in 1989-90, 28% of the population were smokers). Of this decrease, 41% was due to a decline in smoking among 45-64 year olds. However, the greatest reduction in smoking over the period was among 65-74 year olds (down from 17% to 11% between 1989-90 and 2001). In 2001, smoking was highest among 25-34 year olds (32%), and people were less likely to smoke as they reached older age groups. This is partly because smoking is associated with higher premature death rates, and smokers are less likely to live to the older age groups.

In 2001, 27% of men smoked compared with 21% of women. Smoking was consistently higher among men over the period 1989-90 to 2001, despite a slightly greater decline in smoking among men (down 4 percentage points) than among women (down 3 percentage points) over this period. Of all women, those aged 18-24 years experienced the greatest reduction in smoking (from 36% to 27% in 2001), while women aged 35-44 years experienced an increase (up from 25% to 27%).

Adults from the most disadvantaged socioeconomic areas (those in the lowest Socio-Economic Index For Areas (SEIFA) quintile) were more likely to smoke (34% in 2001 compared with 17% of adults from the least disadvantaged socioeconomic areas, i.e. those in the highest SEIFA quintile). Consistent with this, adults without a tertiary education were more than twice as likely to smoke (28% in 2001) compared with those with a tertiary qualification (13%). Smoking was also more prevalent among the unemployed. In 2001, 40% of unemployed adults aged 18-64 years smoked compared with 26% of people aged 18-64 years who were employed.

PROPORTION OF ADULTS WHO WERE CURRENT SMOKERS(a) IN AREAS OF RELATIVE SOCIOECONOMIC DISADVANTAGE(b) - 2001
Graph - Proportion of adults who were current smokers(a) in areas of relative socioeconomic disadvantage(b) - 2001

(a) Age standardised to the 2001 National Health Survey benchmark population.
(b) Based on the Socio-Economic Indexes for Areas (SEIFA).
(c) Where the first quintile represents the 20% of the total population living in areas with the highest levels of disadvantage and the fifth quintile represents the 20% of the total population living in areas with the lowest levels of disadvantage.

Source: ABS 2001 National Health Survey.


Socio-Economic Indexes For Areas
The Socio-Economic Index for Areas (SEIFA) Index of Relative Socio-Economic Disadvantage uses a selection of weighted variables, such as income, educational attainment and employment, to determine the level of disadvantage of a geographic area. Households falling in the lower quintiles have lower index scores. This occurs when the area has a relatively high level of disadvantage, with a high proportion of people on low incomes, who have a low educational attainment, who are in unskilled occupations or who are unemployed. Households in the higher quintiles have higher scores, representing areas with relatively low levels of disadvantage, where there are smaller proportions of people with these characteristics. (See Information Paper: Census of Population and Housing - Socio-Economic Indexes for Areas, Australia, 1996, ABS cat. no. 2039.0).

PROPORTION OF ADULTS WHO WERE PHYSICALLY INACTIVE
Graph - Proportion of adults who were physically inactive

Source: ABS 1989-90, 1995 and 2001 National Health Surveys.


Physical inactivity
The health benefits of engaging in physical activity are numerous, such as offering protection against some cancers, a reduction in the risk of diabetes and cardiovascular disease and improvements in mental health.7 Physical activity may also reduce the risk of injury among older people,7 reduce body fat and improve musculoskeletal health.5 Conversely, physical inactivity increases the risk of developing some cancers such as bowel and breast cancer, coronary heart disease, Type II diabetes and depression, among other conditions.1 In 2001, physically inactive adults were 1.3 times more likely to have coronary heart disease, and 1.2 times more likely to be obese, than those who exercised. This difference was more evident when comparing inactive adults with those who exercised at moderate or high (rather than low) levels. In this case, physically inactive adults were 1.6 times more likely to be obese and 1.7 times more likely to have a high or very high level of psychological distress.

In 2001, 32% of the adult population were physically inactive (that is, they did not undertake deliberate exercise, or did so at a very low level, during the survey reference period). When asked to rate their health, 74% of physically inactive adults considered their health to be better than fair, compared with 81% of the total adult population.

Overall, between 1989-90 and 2001, there was a decrease in physical inactivity among Australian adults. In 1989-90, 38% of Australian adults were physically inactive compared with 32% of adults in 2001. However, this was driven by an increase in the number of adults undertaking light exercise (such as walking), while the proportion of adults exercising at a moderate or high level remained around 30% over the same period. The National Physical Activity Guidelines for Australians suggests undertaking 30 minutes of moderate physical activity on most days of the week.8

PROPORTION OF ADULTS WHO WERE PHYSICALLY INACTIVE(a) IN AREAS OF RELATIVE SOCIOECONOMIC DISADVANTAGE(b) - 2001
Graph - Proportion of adults who were physically inactive(a) in areas of relative socioeconomic disadvantage(b) - 2001

(a) Age standardised to the 2001 National Health Survey benchmark population.
(b) Based on the Socio-Economic Indexes for Areas (SEIFA).
(c) Where the first quintile represents the 20% of the total population living in areas with the highest levels of disadvantage and the fifth quintile represents the 20% of the total population living in areas with the lowest levels of disadvantage.

Source: ABS 2001 National Health Survey.


Over the 12 years to 2001, similar proportions of men and women were physically inactive (31% and 32% in 2001 respectively). However, men were more likely to exercise at a moderate level in 2001 (26%) than women (23%), and to exercise at a high level (9% in 2001 compared with 4% of women).

In 2001, physical inactivity was highest among 65-74 year olds and those aged 75 years and over (35% and 51% respectively). Of adults aged 45-54 years, 32% were physically inactive. This group experienced the largest improvement in level of physical activity over the period 1989-2001 (42% were physically inactive in 1989-90). Older age groups (i.e. those aged 65 years and over) demonstrated the least improvement in physical activity over the period.

Physical inactivity was more common among adults from the more disadvantaged socioeconomic areas (lower SEIFA quintiles). Among adults from the most disadvantaged socioeconomic areas (lowest SEIFA quintile), 40% were physically inactive compared with 25% of adults from the least disadvantaged socioeconomic areas (highest SEIFA quintile).

Overweight and obesity
The proportion of people who are either overweight or obese is increasing worldwide,3 and despite decreases in the proportion of people who are physically inactive, Australians are also carrying more excess weight. The World Health Organisation recognises that globally there was a decrease in the physical energy people expend in everyday living over the second half of the 20th century.3 For example, there is more reliance on motorised transport, and use of labour-saving devices. Changes in the workplace, such as increased use of computers, mean that fewer people now work in physically demanding jobs. Furthermore, there is increased demand for convenience foods which are higher in fat (especially saturated fat).3 People are also more likely now than in the past to participate in leisure activities which involve little, if any, physical activity, such as watching television. In 1997, on average, Australians spent more than half of their free time on such passive leisure activities. Watching television accounted for 36% of all free time.9 Between 1992 and 1997, time spent on outdoor or sporting activities decreased, particularly during the weekends (down, on average, 11 minutes for males and 8 minutes for females aged 15 years and over).9 All of these factors are likely to contribute to the increase in the prevalence of overweight and obese people.

Being overweight or obese is associated with a range of illnesses including coronary heart disease, Type II diabetes, certain types of cancer, gallbladder disease, osteoarthritis and high blood pressure.3 Compared with adults within the acceptable weight range (according to the Body Mass Index - BMI), persons aged 18 years and over who were overweight or obese were 1.9 times more likely to have Type II diabetes and were 1.6 times more likely to have high blood pressure in 2001. The likelihood increased among those adults who were obese. This group was 2.9 times more likely have Type II diabetes, 2.2 times more likely to have high blood pressure, and 1.5 times more likely to have a form of arthritis. However, while adults who were obese were 2.8 times more likely to have any form of diabetes (compared with adults in the acceptable BMI category), the likelihood was less in 2001 than it had been in both 1989-90 and 1995 (approximately 3.2).

In 2001, more than 6.5 million Australian adults were overweight or obese (31% and 15% of the adult population respectively). In addition, the rate at which the population is becoming more overweight or obese has increased. While the proportion of overweight or obesity increased by 3 percentage points in the period 1989-90 to 1995, it increased by 6 percentage points from 1995 to 2001. Consistent with this, the average weight of Australians increased. In 1989-90, the average weight for an Australian adult was 70.1 kilograms. In 2001, this had increased to 74.3 kilograms, equivalent to each Australian gaining more than 350g per year on average over that time. The proportion of adults who were overweight or obese tended to increase with age, peaking among those aged 55-64 years (59% in 2001). This was the case among both males and females (64% and 53% respectively). Men were more likely to be overweight or obese (54% in 2001) than women (38%). However, women were slightly more likely to be obese than men.

Growth in the proportion of adults who were overweight or obese was stronger among the older age groups. The rate of increase was greatest among those aged 65-74 years (up from 44% in 1989-90 to 56% in 2001). Between 1995 and 2001, the prevalence of overweight and obesity increased from 45% to 56% among this group. The rate of increase was also higher among men, with a 10 percentage point increase since 1989-90, compared with a 7 percentage point increase for women.

The prevalence of overweight or obesity is higher among certain groups in the population than others. For example, in 2001, 39% of men from the least disadvantaged socioeconomic areas (highest SEIFA quintile) were overweight compared with 35% of men from the most disadvantaged socioeconomic areas (lowest SEIFA quintile). Conversely, there was a higher prevalence of obesity among women from the most disadvantaged socioeconomic areas (19%) than among women from the least disadvantaged socioeconomic areas (11%). Adults living outside of Capital Cities were also more likely to be overweight or obese (49%) than those in the Capital Cities (45%). There were similar patterns of differences in 1995.

ADULTS: RISK FACTOR COMBINATIONS: ASSOCIATIONS WITH SELECTED DISEASES(a) - 2001
Risk factor
Prevalence
Relative prevalence of selected conditions(a)



Current smoker?Physically inactive?Overweight
or obese?
‘000
%
Coronary heart disease
Type II diabetes
Arthritis
Malignant cancer
High
blood pressure
High cholesterol

NoNoNo
3,542.7
25.0
1.0
1.0
1.0
1.0
1.0
1.0
NoYesNo
1,304.1
9.2
1.5
0.6
1.2
0.6
1.1
1.0
NoNoYes
3,551.6
25.0
1.2
1.5
1.3
1.0
1.6
1.4
YesNoNo
1,081.8
7.6
*0.7
*0.7
1.0
*0.8
0.8
0.8
NoYesYes
1,555.2
11.0
1.6
1.9
1.5
1.1
1.9
1.6
YesYesNo
605.9
4.3
*1.8
*0.7
1.4
*0.8
0.9
1.1
YesNoYes
886.2
6.2
*1.1
2.3
1.4
*1.3
1.4
1.6
YesYesYes
558.6
3.9
*2.0
2.0
1.5
*0.7
1.0
1.2

Total persons aged 18 years and over(b)
14,184.7
100.0
1.3
1.4
1.3
0.9
1.4
1.2

(a) Measures the likelihood of having a particular condition given the presence of certain risk factor(s), compared with the likelihood of having the condition among the population who did not have any of the three risk factors.
(b) Includes persons whose Body Mass Index was not stated or not known.

Source: ABS 2001 National Health Survey.


Combined risk factors
In 2001, 4% of the Australian adult population (more than half a million people) had all three of the risk factors discussed in this article. That is, this group were physically inactive, smoked and were either overweight or obese. Compared with the quarter of the adult Australian population who did not have any of these three risk factors, this group were 2.0 times more likely to have Type II diabetes and 1.5 times more likely to have a form of arthritis.

The likelihood of having certain conditions (e.g. high cholesterol) was not much higher for the group with all three risk factors, than it was for those without any of the risk factors. However, the likelihood increased when ex-smokers were included in the analysis. That is, those adults who were current or ex-smokers, physically inactive and overweight or obese were 2.4 times more likely to have coronary heart disease, 1.5 times more likely to have high blood pressure, and 1.7 times more likely to have a malignant cancer than adults who had never smoked, were active and were neither overweight nor obese.

Among those adults without any of the three risk factors discussed individually in this article, 65% rated their own health as very good or excellent. This compared with 32% of adults who were current smokers, overweight or obese and physically inactive, who rated their health as very good or excellent.

Endnotes
1 Mathers, C., Vos, T. and Stevenson, C. 1999, The burden of disease and injury in Australia, AIHW, Canberra.
2 Australian Institute of Health and Welfare 2001, Chronic diseases and associated risk factors in Australia, AIHW, Canberra.
3 World Health Organisation 2000, Obesity: preventing and managing the global epidemic, WHO Technical Series: No. 894, WHO, Geneva.
4 Australian Bureau of Statistics 1995, National Nutrition Survey: Selected Highlights, Australia, cat. no. 4802.0, ABS, Canberra.
5 World Health Organisation 2002, The World health report 2002, WHO, Geneva.
6 Riddolfo, B. and Stevenson, C. 2001, The quantification of drug-caused mortality and morbidity in Australia, 1998, AIHW, Canberra.
7 Armstrong, T., Bauman, A. and Davies, J. 2000, Physical activity patterns of Australian adults. Results of the 1999 National Physical Activity Survey, Australian Institute of Health and Welfare, Canberra.
8 Commonwealth Department of Health and Aged Care 1999, National physical activity guidelines for Australians <www.health.gov.au/pubhlth/publicat/strateg/active/who.htm>, accessed 25 March 2003.
9 Australian Bureau of Statistics 1998, How Australians Use Their Time, cat. no. 4153.0, ABS, Canberra.



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