Understanding lifestyle risk factors

In 2018, 38% of the burden of disease could have been prevented by reducing or avoiding exposure to 20 modifiable risk factors such as tobacco use, overweight (including obesity), and physical inactivity (AIHW 2021a). The risk factors are ‘modifiable’ because with lifestyle, environmental and metabolic changes, population risk exposure can be reduced. For example, a person could reduce their level of physical inactivity by taking a walk every day or reduce their BMI by losing weight.

Understanding the role that risk factors play in health and burden of disease is important for improving health outcomes and health service planning and delivery. Increased exposure increases the risk of developing diseases linked to the risk factor.

In 2018, 8.4% of the total disease burden was attributable to overweight (including obesity), making it the second leading risk factor contributing to disease burden after tobacco use (AIHW 2021a). Overweight (including obesity) was the leading risk factor contributing to non-fatal burden (living with disease), responsible for 7.4% of all non-fatal burden, and was the second-leading contributor to fatal burden (dying prematurely), contributing 16,400 deaths (10% of all deaths). It contributed to the burden of 30 diseases including 17 types of cancer, 4 cardiovascular diseases, 3 musculoskeletal conditions, type 2 diabetes, dementia, asthma and chronic kidney disease. 

Overweight (including obesity) was responsible for more than 55% of type 2 diabetes disease burden, 51% of hypertensive heart disease burden, 42% of chronic kidney disease burden, 28% of coronary heart disease burden, and more than 28% of the burden from osteoarthritis (AIHW 2021a).

In 2018, physical inactivity accounted for 2.5% of the total disease burden in Australia and 8,300 deaths, making it the ninth leading risk factor contributing to disease burden (AIHW 2021a). It was also the 10th leading risk factor in terms of non-fatal burden and ninth for fatal burden. Physical inactivity is linked to an increased risk of type 2 diabetes, bowel cancer, dementia, coronary heart disease and stroke, as well as uterine and breast cancer in females.

In 2018, overweight (including obesity) and physical inactivity jointly accounted for 8.7% of the total burden in Australia – greater than tobacco smoking (8.6%), which was the leading risk factor for disease burden in Australia in 2018.

More results on the burden attributable to risk factors can be found in the Australian Burden of Disease Study (ABDS) 2018: Interactive data on risk factor burden.

The scenario modelling in this report includes depressive disorders as a linked disease for the first time, due to growing evidence of its association with physical inactivity (Pearce et al. 2022).

Increasing physical activity and reducing body mass index have several benefits for individuals and the broader health system including:

  • reducing the risk of poor health outcomes
  • reducing the number of years of healthy life lost
  • reducing the cost of health care and aged care
  • improving health service planning and delivery (AIHW 2021b).

Policies encouraging greater physical activity can also lead to more active transport (such as walking or cycling), reduced emissions and increased promotion of green space (AIHW 2022, WHO 2018).