Prevalence of risk factors for chronic diseases

Risk factors are highly prevalent in Australia. For example, 17% of Australians aged 14 years and over are daily smokers, and 10% drank alcohol at risky levels. Thirty per cent of Australians aged 25 years and over had high blood pressure, 50% of Australians adults aged 25 years and over had high blood cholesterol levels, and 60% carried excess weight.

Risk factors that affect the onset, maintenance and prognosis of a variety of chronic diseases include:

• poor diet and nutrition
• physical inactivity
• tobacco smoking
• alcohol misuse
• high blood pressure
• high blood cholesterol
• excess weight.

Prevalence estimates are based on either self-reported or measured data from various national surveys (see Risk factors for detailed data sources and other information).

Poor diet and nutrition

There have been limited data collected in recent years on food and nutrient intake of Australians. National data are available mainly from the 1983 National Dietary Survey of Adults, the 1985 National Dietary Survey of School Children and the 1995 National Nutrition Survey. Nutrition-related data are also available from the National Health Surveys (most recently for 2004-05), from short dietary questions.

It is recommended that Australians consume five serves of vegetables and two serves of fruit each day for good health and to reduce the risk of disease. From the 2004-05 National Health Survey, 80-90% of Australians report usually consuming inadequate serves of vegetables, and over 50% report inadequate serves of fruit (Figure 1). Women are more likely to report consuming adequate fruit and vegetables than men, and older people are more likely to consume adequate amounts than younger people.

Data from the 1995 National Nutrition Survey indicate a high consumption of total fat and saturated fat, with 32.5% of energy intakes of Australians aged 19 and over coming from fat (maximum recommended level, 30%), of which 12.5% is from saturated fats (maximum recommended level, 10%).

There have been significant changes in food and nutrient intake in the Australian population in the past two decades. For both adults and children, intake of energy, dietary fibre, carbohydrate and iron all increased significantly during this period (Table 2). The calcium intake among adults and protein consumption among children also increased considerably. By contrast, fat intake among adults decreased. There was a decrease in vitamin C consumption, largely attributable to a fall in fruit consumption among adults and fruit juices among children.

(a) Where there is a trend in mean intake it is significant at 1% level.

Source: Cook et al. 2001. Comparable data on food and nutrient intake and physical measurements from the 1983, 1985 and 1995 national surveys. Canberra: Department of Health and Ageing.

Physical inactivity

Estimates from the ABS 2004-05 National Health Survey and the 2004 State and Territory Computer Assisted Telephone Interviewing (CATI) surveys suggest that around 50% of adults are not undertaking sufficient physical activity (Figure 1).

In addition, data from the National Physical Activity Surveys suggest that there were declines in physical activity between 1997 and 2000 for adult Australians. The proportion of Australians reporting lower-than-recommended levels of physical activity rose from 38% to 43% (age-standardised). These declines were also observed across all age groups, with exception of those aged 60-75 for whom activity levels remained fairly stable (Figure 2). The greatest increase in insufficient or no physical activity was seen among those aged 30-44, from 36% to 46%.

Physical inactivity data are available in the Risk factor data store on the AIHW website.

Tobacco

Estimates from the 2004 National Drug Strategy Household Survey indicate that around 17.4% of Australians aged 14 years and over (2.9 million) smoked tobacco daily (smoking at least once a day). A further 3.2% reported occasional smoking (smoking less than daily, that is once a week or less than once a week), and a further 26.4% were former smokers (smoked more than 100 cigarettes or the equivalent amount of tobacco in their life, and reporting no longer smoking). 52.9% had never smoked. Males were more likely to be daily smokers, with a rate of 18.6%, compared with 16.3% for females.

Daily smoking was most prevalent in the 20-29 age group (23.5% males and 22.9% females), and lowest among those 60 and over (8.9% and 7.1% respectively) (Figure 3). Among teenagers aged 14-19 years, 10.7% were daily smokers, with 11.9% and 9.5% for girls and boys respectively. For all other ages, males had higher daily smoking rates than females.

Daily smoking rates in Australia have been declining since the 1950s, when it was estimated that around 70% of males and 30% of females smoked. Between 1985 and 2004, daily smoking rates for Australians aged 14 years and over have declined by 40% (Figure 4).

The impact of smoking can been seen in both the increases and decline in COPD and lung cancer death rates among males, which occurred about 20 years after the increase and decline in tobacco consumption in Australia (Figure 5).

Tobacco smoking data are available in the Risk factor data store on the AIHW website.

Alcohol misuse

The National Health and Medical Research Council Australian Alcohol Guidelines are used to assess the prevalence of alcohol misuse.

Results from the 2004 National Drug Strategy Household Survey show that around 16% of Australians aged 14 years and over abstained from alcohol, 74% consumed alcohol at levels considered a low risk to health in the long term, and 10% at levels considered risky or a high risk to health in the long term (Table 3).

The proportion of males and females drinking at risky or high risk levels for harm in the long term were similar, with one in ten Australians consuming alcohol at this level.

Note: Abstainers refer to those who did not consume alcohol in the last 12 months.

Source: AIHW 2005. Statistics on drug use in Australia 2004. AIHW cat. no. PHE 62. Canberra: AIHW (Drug Statistics Series no. 15).

People in the 20-29 age group and females aged 15-19 are most likely to drink at levels considered risky or a high risk for long term alcohol related harm (Figure 6).

Alcohol consumption data are available in the Risk factor data store on the AIHW website.

High blood pressure

Data from the 1999-2000 Australian Diabetes, Obesity and Lifestyle Study indicate that 30% or 3.7 million Australians over the age of 25 years had high blood pressure or were on medication for that condition - 32% of men and 27% of women. The proportion of men and women with high blood pressure increased with age (Figure 7).

Since 1980 the prevalence of high blood pressure has decreased markedly for both males and females (Figure 8). The proportion of men aged 25-64 years with high blood pressure has more than halved from 47% in 1980 to 21% in 1999-2000 and has halved for women from 32% in 1980 to 16% in 1990-2000.

Blood pressure data are available in the Risk factor data store on the AIHW website.

High blood cholesterol

The 1999-2000 Australian Diabetes, Obesity and Lifestyle Study found that around 50% of men and women in Australia had high blood cholesterol levels, that is, nearly 6.5 million Australian adults aged 25 years and over. The prevalence increased with age, reaching 74% for women aged 65-74 and 62% for men aged 55-64 in men (Figure 9).

There has been no apparent reduction in the prevalence of people with high blood cholesterol since 1980 (Figure 10).

Blood cholesterol data are available in the Risk factor data store on the AIHW website.

Excess weight

The most recent national estimates of levels of excess weight in the Australian population are based on self-reported data from the 2004-05 National Health Survey. The most recent measured data are from the 1999-2000 Australian Diabetes, Obesity and Lifestyle Study (AusDiab). The survey measured height, weight (which are used to calculate body mass index) and waist circumference.

Body mass index (BMI)

According to the National Health Survey (and excluding those for whom BMI could not be derived), 19% of males and 17% of females aged 18 years and over were obese. This equates to 2.5 million Australian adults. An additional 4.9 million adults were estimated to be overweight but not obese (41% of males and 25% of females) (Figure 11). In both males and females, excess weight increases with age, peaking in the 55-64 age group.

Data based on measured data were last collected nationally in 1999-2000. Measured data collected since 1980 shows that excess weight as measured by BMI appears to have increased. The proportion of males aged 25-64 with excess weight increased from 47% in 1980 to 67% in 1995, before declining slightly to 65% in 1999-2000. The proportion increased from 26% to 48% for females from 1980 to 1995, with a decline to 45% in 1999-2000 (Figure 11). Looking just at the population classified as obese, the proportions increased from around 8% for both males and females in 1980 to 16% for males and 19% for females in 1999-2000.

BMI data are available in the Risk factor data store on the AIHW website.

Waist circumference

According to the waist circumference measurements in the 1999-2000 Australian Diabetes, Obesity and Lifestyle Study, an estimated 27% of adult males and 34% of adult females are classified as abdominally obese. A further 20% of males and 22% of females were classified as abdominally overweight but not obese.