The burden of low physical activity in Australia: a comprehensive comparative risk assessment

Estimating the effects of physical activity on disease burden is important to inform public health policies. Standard comparative risk assessments underestimate disability-adjusted life-years (DALYs) attributable to low physical activity (LPA), because: (1) direct effects of physical activity on mental health and falls are not included, (2) impacts from changes in blood pressure, plasma glucose, LDL cholesterol, and bone mineral density are excluded, and (3) meta-analyses for relative risks (RRs) overadjust mediators. This study aimed to re-estimate DALYs attributable to LPA (activity below the >4200 metabolic minimum task mins per week minimum risk level) in Australia.

In this comparative risk assessment, we used the Australian Burden of Disease Study 2024 as the framework to assess DALYs attributable to LPA in Australia in calendar year 2024. Participants were Australians older than 20 years. In our analysis we also included associations of physical activity with depression and anxiety (and falls in sensitivity analyses), and the additional risk factors (high plasma glucose and diabetes, blood pressure, LDL cholesterol, and bone mineral density), from published systematic reviews and meta-analyses (and a bespoke analysis for LDL cholesterol). To account for the overadjustment of mediators, we calculated the RR overadjustment.

The DALYs attributable to LPA were 200 000 (95% uncertainty interval 146 000-254 000), which was 68·1% greater than the attributable burden using standard burden of disease study methods (119 000 DALYs [98 900-139 000]). Of this 81 000 DALYs (47 100-115 000) increase, 40 100 DALYs (29 300-50 900) were due to the direct effects on depression and anxiety, 24 900 DALYs (14 200-35 600) were due to including the additional disease effects from risk factors impacted by physical activity, and 15 900 DALYs (3180-28 700) were due to estimated mediator overadjustment.

Attributable burden of LPA in Australia is underestimated. This underestimation most probably also applies to LPA burden in other countries using standard methodologies. Expanding the model structure to comprehensively estimate the burden of LPA provides a more accurate assessment to inform public health interventions and prevention programmes.

Australian Sports Commission.