Risk factors and multimorbidity
Page highlights:
Multimorbidity among people with selected risk factors
Of 6 selected risk factors, not usually eating any serves of fruit or vegetables daily was associated with the highest proportion of multimorbidity among adults in 2022. An estimated 60% of adults with this risk factor were living with multimorbidity.
Number of risk factors and multimorbidity
Multimorbidity is more common among people with more risk factors.
In 2022, the estimated proportion of adults aged 18 and over living with multimorbidity was higher among those with 4 or more of the selected risk factors (59%) compared with those with no risk factors (29%).
About the data
There is a complex relationship between risk factors and multimorbidity. Information on an individual’s exposure to each risk factor over time and the timing of condition onset is not available in the Australian Bureau of Statistics (ABS) 2022 National Health Survey (NHS) (ABS 2023) used in this analysis. It is therefore not possible to know if the number of risk factors – or specific risk factors – a person has caused their multimorbidity.
This is because the onset of some chronic conditions may motivate a person to change their behaviour for the better. For example, a diagnosis of chronic obstructive pulmonary disease may motivate a person to quit smoking. In contrast, the onset of a chronic condition such as arthritis may result in an individual being less able to participate in physical activity.
Furthermore, the analysis does not account for potential interactions between risk factors and other individual characteristics such as socioeconomic status, regionality and employment status. Results presented here therefore highlight broad associations between risk factors and multimorbidity only.
Age-standardised rates are used to remove the influence of age when comparing populations with different age structures. Unless otherwise stated, crude rates are reported, and age-standardised rates are used to inform whether comparisons between population groups are statistically significant. Only statistically significant differences are reported.
Estimates on this page are of adults aged 18 and over from AIHW analysis of the ABS 2022 NHS (ABS 2023).
For more information on the data source, see Technical notes.
Risk factors included in analysis
According to the 2024 Australian Burden of Disease Study (ABDS), 36% of disease burden in Australia due to modifiable risk factors could have been avoided or reduced (AIHW 2024a). Risk factors captured in the ABDS include overweight (including obesity), tobacco use, all dietary risks, high blood pressure, alcohol use and physical inactivity. These risk factors were among the highest contributors to disease burden, accounting for 19% of total disease burden and 54% of the burden due to modifiable risk factors in 2024, after adjusting for the combined effect of all risk factors in the study (AIHW 2024b). For more detail, see Australian Burden of Disease Study 2024, leading risk factors.
While it is not possible to capture these risk factors as they are defined in the ABDS using the NHS, the following six risk factors are included in analysis on this page, based on data availability in the NHS:
- Alcohol use – defined in analysis on this page as use exceeding the 2020 National Health and Medical Research Council (NHMRC) Australian guidelines to reduce health risks from drinking alcohol based on self-reported data.
- Dietary risks – the NHS collects self-reported information on the number of usual daily serves of fruit and usual daily serves of vegetables. While this is a subset of the range of dietary risks measured in the ABDS, these measures can be assessed against the recommended fruit and vegetable consumption guidelines provided by the NHMRC 2013 Australian Dietary Guidelines. However, an estimated 96% of adults did not consume the recommended serves of fruit and vegetables daily based on self-reported 2022 NHS data (Data table MM08). Due to the high number of adults who did not meet these guidelines, this analysis focused on the group of people with the highest dietary risk that could be identified using the available data. In this report, people who reported usually having no serves of fruit or vegetables daily were considered to be the most at-risk group and have the risk factor (an estimated 1% of the population). People who reported usually having at least one serve of fruit or vegetables daily had lower risk and did not have the risk factor.
- Measured high blood pressure (hypertension) – measured systolic/diastolic blood pressure equal to or greater than 140/90 mmHg, excluding self-reported hypertension. Measured high blood pressure can indicate that a person may have hypertension or that their hypertension is uncontrolled, regardless of whether the individual is taking high blood pressure medication or not.
- Insufficient physical activity – defined in analysis on this page as not meeting the Physical activity and exercise guidelines for all Australians. For people aged 18–64, sufficient physical activity is defined as completing 150 minutes of moderate to vigorous activity across 5 or more days a week (including workplace activity) and completing muscle-strengthening activities 2 times a week. For people aged 65 and over, sufficient physical activity is defined as 30 minutes of moderate activity on most, preferably all, days. This is interpreted in this analysis as at least 5 days of physical activity for at least 30 minutes, including workplace activity.
- Measured overweight or obesity – having a body mass index of 25 or greater. Body mass index is used to identify risk due to overweight and obesity as waist-to-height ratio information is not collected by the NHS.
- Tobacco use – self-reported current daily smoking at the time of the survey is used to report on tobacco use, noting this will underestimate the risk from nicotine use as it does not capture those who smoked less than daily, previous daily smokers or nicotine vaping.
For further details of how these risk factors were measured in analysis, see Derived variables in the Technical notes.
Some chronic conditions cannot be prevented because they are genetic, or the cause is unknown. Other chronic conditions share risk factors that are largely preventable.
Modifying these risk factors can reduce an individual's risk of developing a chronic disease and result in enhanced health outcomes as well as reduced burden and multimorbidity. Individuals have an important role in the effective self-management of modifiable risk factors to reduce the risk of future multimorbidity.
For more information on health risk factors, see What are determinants of health?
Multimorbidity among people with selected risk factors
In 2022, the estimated prevalence of multimorbidity among all adults was 45% however multimorbidity was more common among adults:
- who did not usually eat any serves of fruit or vegetables daily – 60% of adults who did not usually eat any serves of fruit or vegetables daily were living with multimorbidity (137,000 adults)
- with current daily smoking – 55% of adults who smoked daily were living with multimorbidity (1.2 million adults)
- with high blood pressure – 54% of adults with high blood pressure were living with multimorbidity (2.5 million adults)
- with overweight or obesity – 50% of adults living with overweight or obesity were living with multimorbidity (6.4 million adults)
- with alcohol consumption exceeding the 2020 guidelines – 46% of adults who exceeded the guidelines were living with multimorbidity (2.4 million adults) (Figure 12).
A closer look at alcohol consumption and multimorbidity
The 2020 alcohol consumption guidelines comprise 2 components. Among adults who exceeded the combined alcohol consumption guidelines:
- 50% of those who consumed more than 10 standard drinks in the past week were living with multimorbidity
- 43% of those who drank 5 or more standards drinks on any day in the last 12 months, at least monthly were living with multimorbidity (Data table MM08).
Figure 12: Proportion of adults with selected risk factors living with 0, 1 or 2 or more long-term health conditions, 2022
This figure shows that the risk factors associated with the lowest proportion of adults living with none of the selected long-term health conditions were not eating any fruit or vegetables daily, current daily smoking and high blood pressure. An estimated 24% of adults with these risk factors were not living with a long-term health condition.
Notes:
- For the list of long-term health conditions included in analysis, see Table 1 in the Technical notes.
- The comparison group for 'Overweight or obesity' is 'Normal weight'. For estimates for people who were 'Underweight' and further footnotes, see Table MM08 in the Data tables.
After adjusting for age, multimorbidity among adults was significantly more common among those exposed to each risk factor, compared with those who were not. In 2022, based on age-standardised ratio ratios, multimorbidity was estimated to be:
- 1.4 times as high among those who did not usually eat fruit or vegetables daily compared with those who did
- 1.4 times as high among those who smoked daily at the time of survey compared with those who did not smoke daily (including those who smoked less than daily and previous daily smokers)
- 1.3 times as high among those living with overweight or obesity compared with those who were of normal weight
- 1.1 times as high among those living with high blood pressure compared with those without high blood pressure
- 1.1 times as high among those who exceeded the combined 2020 alcohol consumption guidelines compared with those who did not
- 1.1 times as high among those who did not meet the physical activity guidelines compared with those who met the guidelines (Data table MM08).
Number of risk factors and multimorbidity
Multimorbidity is more common among people with more risk factors.
In 2022, the proportion of adults living with multimorbidity (2 or more of the selected long-term health conditions) increased with the number of risk factors experienced.
Among adults aged 18 and over in 2022, the estimated prevalence of multimorbidity was:
- 29% among those with no risk factors
- 34% among those with one risk factor
- 46% among those with 2 risk factors
- 52% among those with 3 risk factors
- 59% among those with 4 or more risk factors (Figure 13).
Figure 13: Proportion of adults with 0, 1 or 2 or more long-term health conditions by number of risk factors, 2022
This figure shows that the proportion of adults estimated to be living with none of the selected long-term health conditions was highest among those with none of the selected risk factors (42%) and lowest among those with 4 or more risk factors (18%).
Notes:
- The selected risk factors are: exceeded 2020 alcohol guidelines, current daily smoking, overweight or obesity (combined), insufficient physical activity and strength training (combined), hypertension, not usually eating fruit or vegetables daily.
- For the list of long-term health conditions included in analysis, see Table 1 in the Technical notes.
- For data and footnotes, see Table MM09 in the Data tables.
It is important to note that the current analysis, based on counts of the number of risk factors an individual has, does not account for differences in the health impact different risk factors may have on individuals.
Furthermore, the analysis does not account for potential interactions between risk factors and other individual characteristics such as socioeconomic status, regionality and employment status.
ABS (Australian Bureau of Statistics) (2023) Microdata: National Health Survey, 2022, AIHW analysis of detailed microdata, accessed 15 February 2025.
AIHW (Australian Institute of Health and Welfare) (2024a) Australian Burden of Disease Study 2024, AIHW, Australian Government, accessed 3 March 2025.
AIHW (2024b) Data tables: ABDS 2024 National estimates for Australia, Table S7: Number and percent of total burden (deaths, YLL, YLD, DALY) in Australia due to each risk factor adjusted for the joint effect, by sex and year, Australian Burden of Disease Study 2024, AIHW, Australian Government, accessed 3 March 2025.
AIHW (2024c) Diet, AIHW, Australian Government, accessed 27 March 2025.