Which risk factors cause most deaths?

Another way of looking at what causes death is to measure the number of deaths that can be attributed to risk factors, for example, tobacco use, high blood pressure and physical inactivity.

The involvement of certain health-related risk factors can to some extent be identified in cause of death information provided on the death certificate. For example, in 2022, hypertension was involved in causing 12% of deaths.

However, the recording of this information on death certificates is not as rigorous as data collected on exposure to risk factors and the assessments of causal association with different diseases through surveys and epidemiological research. It is also not possible to fully estimate the number of attributable deaths due to selected risk factors using multiple causes of death data. Burden of disease methodology can be used to estimate the fatal burden of disease attributable to risk factors.

To get a more complete picture of the impact of risk factors on causing death, we used the Australian Burden of Disease Study (ABDS). This study identifies a set of known and modifiable health-related risk factors, which have been measured in the Australian population.

Tobacco use causes the most deaths attributable to risk factors

The disease burden attributable to 20 individual risk factors includes an estimate of the number of deaths attributable to each risk factor (AIHW 2021). Figure 9.1 shows the risk factors that caused the highest number of deaths in 2011, 2015 and 2018. Exposure to tobacco use led to the highest number of attributable deaths in all years (see Figure 9.1). Exposure to high blood pressure, overweight (including obesity) and dietary risks were the next leading causes of attributable death. All risk factors included in the ABDS accounted for 49% of all deaths in 2018.

The number of deaths attributable to some risk factors decreased over time. For example, comparing 2011 and 2018, there were fewer deaths attributable to high blood pressure, dietary risks and high cholesterol (Figure 9.1). For some risk factors, such as overweight (including obesity) and alcohol use, the number of deaths rose over this period (Figure 9.1). The number of deaths attributable to illicit drug use increased by 44% between 2011 and 2018.

As the number of deaths can increase each year due to population growth and ageing, the proportion of deaths in each year attributable to the risk factors can also be examined to highlight changes over time. Though the number of deaths attributable to tobacco use rose between 2011 and 2018, the proportion of deaths attributable to this risk factor decreased slightly from 13.5% to 12.9% (Figure 9.1). Alongside a declining number of attributable deaths, the proportion of deaths due to high blood pressure declined, from 13.2% to 10.9%, and for dietary risks, from 12.0% to 9.9%. The number and proportion of deaths attributable to overweight (including obesity), alcohol use and illicit drug use increased over the period are shown here.

Figure 9.1: Number and per cent of deaths attributable to risk factors, 2011, 2015, 2018

Number and percent of risk factor attributable deaths from the 2018 Australian Burden of Disease Study. Across all years (2011, 2015, 2018) tobacco use caused the most attributable burden (13.5%, 13.3%, 12.9%). High blood pressure, all dietary risks, and high cholesterol decreased the most between 2011-2018. Overweight (including obesity) increased the most.


  1. Burden attributable to air pollution was not estimated in 2011.
  2. All dietary risks refers to the joint attributable fatal burden for each dietary risk factor; Illicit drug refers to the joint attributable fatal burden for each type of drug use.
  3. The number and per cent of attributable deaths for individual risk factors cannot be summed to estimate the combined impact as the risk factors were assessed independently.

Source: AIHW (2021); Table S9.1.