Physical Activity and Depression and Anxiety Disorders: A Systematic Review of Reviews and Assessment of Causality.

Introduction: Globally, depressive and anxiety disorders are the leading contributors to mental ill health. Physical activity reduces symptoms of depression and anxiety and has been proposed as an adjunct treatment therapy for depression and anxiety. Prospective studies suggest that physical activity may reduce the incidence of depression and anxiety. We conducted a systematic review of reviews with the aim to provide a comprehensive overview of available epidemiologic evidence on the strength of the association between physical activity and incident cases of depression and anxiety and to assess the likelihood of these associations being causal. Methods: We searched Embase and PubMed databases for systematic reviews published between January 1, 2000 and March 19, 2020 that reported findings on the strength of association between physical activity and incidence of depression and anxiety. We updated this search to October 15, 2022. Two reviewers independently assessed the methodologic quality of the included reviews using the Assessment of Multiple Systematic Reviews rating scale. We carried out a narrative synthesis of the evidence. We used the Bradford Hill criteria to assess the likelihood of associations being causal. Results: The initial search yielded 770 articles, of which 4 remained for data extraction. Two of the included reviews were scored as high quality, and 2 were scored as low quality. From the 2 included reviews that reported pooled estimates, people with high physical activity levels were found to have a decreased risk of incident depression (adjusted RR=0.83, 95% CI=0.76, 0.90) and reduced odds of developing anxiety (adjusted OR=0.74,95% CI=0.62, 0.88) when compared with those with low physical activity levels. We assessed physical activity to be probably causally related to both depression and anxiety. Discussion: Our evidence is drawn from systematic reviews of observational data. Further high-quality studies, such as randomized control trials, would help to strengthen the evidence base of the associations between physical activity and depression and anxiety. Nonetheless, our findings provide empirical support for the consideration of physical activity in strategies for the prevention of mental ill health.

Physical Activity and Depression and Anxiety Disorders in Australia: A Lifetable Analysis.

Introduction: Mental disorders, in particular, depressive and anxiety disorders, are a leading cause of disability in Australia and globally. Physical activity may reduce the incidence of anxiety and depression, and this supports the inclusion of physical activity in strategies for the prevention of mental ill health. Policy makers need to know the potential impact and cost savings of such strategies. We aimed to quantify the impact of changes in physical activity on the burden of anxiety and depression and healthcare costs in Australia. Methods: We used a proportional multistate lifetable model to estimate the impact of changes in physical activity levels on anxiety and depression burdens for the 2019 Australian population (numbering 24.6 million) over their remaining lifetime. The changes in physical activity were modeled through 3 counterfactual scenarios informed by policy targets: attainment of the Australian Physical Activity Guidelines and achievement of the WHO Global Action Plan on Physical Activity targets of a 10% relative reduction in the prevalence of insufficient physical activity by 2025 and a 15% relative reduction by 2030. Results: If all Australians adhered to the recommended minimum physical activity levels, in 25 years' time, the burden of anxiety could be reduced by up to 6.4% (95% uncertainty intervals=2.5, 10.6), and that of depression could be reduced by 4.4% (95% uncertainty intervals=2.3, 6.5). Over the lifetime of the 2019 Australian population, the gains could add up to 640,592 health-adjusted life years for anxiety (26 health-adjusted life years per 1,000 persons), 523,717 health-adjusted life years for depression (21 health-adjusted life years per 1,000 persons), and healthcare cost savings of 5.4 billion Australian dollars for anxiety (220 Australian dollars per capita) and 5.8 billion for depression (237 Australian dollars per capita). Conclusions: Adherence to the Australian physical activity guidelines and achievement of the 2025 and 2030 global physical activity targets could lead to a substantial reduction of the burden of anxiety and depression. This study provides empirical support for the inclusion of physical activity in strategies for the prevention of mental ill health. Future studies should also assess the size and distribution of the benefits for different socioeconomic and ethnic groups.

The Potential Impact of Physical Activity on the Burden of Osteoarthritis and Low Back Pain in Australia: A Systematic Review of Reviews and Life Table Analysis.

OBJECTIVE: The objectives were (1) to establish the strength of the association between incident cases of osteoarthritis (OA) and low back pain (LBP), and physical activity (PA) and to assess the likelihood of the associations being causal; and (2) to quantify the impact of PA on the burden of OA and LBP in Australia. METHODS: We conducted a systematic literature review in EMBASE and PubMed databases from January 01, 2000, to April 28, 2020. We used the Bradford Hill viewpoints to assess causality. We used a proportional multistate life table model to estimate the impact of changes in the PA levels on OA and LBP burdens for the 2019 Australian population (aged ≥ 20 y) over their remaining lifetime. RESULTS: We found that both OA and LBP are possibly causally related to physical inactivity. Assuming causality, our model projected that if the 2025 World Health Organization global target for PA was met, the burden in 25 years' time could be reduced by 70,000 prevalent cases of OA and over 11,000 cases of LBP. Over the lifetime of the current adult population of Australia, the gains could add up to approximately 672,814 health-adjusted life years (HALYs) for OA (ie, 27 HALYs per 1000 persons) and 114,042 HALYs for LBP (ie, 5 HALYs per 1000 persons). The HALY gains would be 1.4 times bigger if the 2030 World Health Organization global target for PA was achieved and 11 times bigger if all Australians adhered to the Australian PA guidelines. CONCLUSION: This study provides empirical support for the adoption of PA in strategies for the prevention of OA and back pain.

What Is the Best Practice Method for Quantifying the Health and Economic Benefits of Active Transport?

The aim of this study was to identify a best practice method to cost the health benefits of active transport for use in infrastructure planning in New South Wales, Australia. We systematically reviewed the international literature covering the concept areas of active transport and cost and health benefits. Original publications describing a method to cost the health benefits of active transport, published in 2000-2019 were included. Studies meeting the inclusion criteria were assessed against criteria identified in interviews with key government stakeholders. A total of 2993 studies were identified, 53 were assessed for eligibility, and 19 were included in the review. The most commonly studied active transport modes were cycling (n = 8) and walking and cycling (n = 6). Exposures considered were physical activity, road transport related injuries and air pollution. The most often applied economic evaluation method was cost benefit analysis (n = 8), and costs were commonly calculated by monetising health outcomes. Based on evaluation of models against the criteria, a Multistate Life Table model was recommended as the best method currently available. There is strong and increasing interest in quantifying and costing the health benefits of active transport internationally. Incorporating health-related economic benefits into existing regulatory processes such as cost benefit analyses could provide an effective way to encourage the non-health sector to include health impacts in infrastructure measures.