Association Between Physical Activity and Risk of Depression: A Systematic Review and Meta-analysis.
JAMA psychiatry 2022
PubMed ID : 35416941
PMCID : PMC9008579
Depression is the leading cause of mental health-related disease burden and may be reduced by physical activity, but the dose-response relationship between activity and depression is uncertain.
To systematically review and meta-analyze the dose-response association between physical activity and incident depression from published prospective studies of adults.
PubMed, SCOPUS, Web of Science, PsycINFO, and the reference lists of systematic reviews retrieved by a systematic search up to December 11, 2020, with no language limits. The date of the search was November 12, 2020.
We included prospective cohort studies reporting physical activity at 3 or more exposure levels and risk estimates for depression with 3000 or more adults and 3 years or longer of follow-up.
Data extraction was completed independently by 2 extractors and cross-checked for errors. A 2-stage random-effects dose-response meta-analysis was used to synthesize data. Study-specific associations were estimated using generalized least-squares regression and the pooled association was estimated by combining the study-specific coefficients using restricted maximum likelihood.
The outcome of interest was depression, including (1) presence of major depressive disorder indicated by self-report of physician diagnosis, registry data, or diagnostic interviews and (2) elevated depressive symptoms established using validated cutoffs for a depressive screening instrument.
Fifteen studies comprising 191 130 participants and 2 110 588 person-years were included. An inverse curvilinear dose-response association between physical activity and depression was observed, with steeper association gradients at lower activity volumes; heterogeneity was large and significant (I2 = 74%; P < .001). Relative to adults not reporting any activity, those accumulating half the recommended volume of physical activity (4.4 marginal metabolic equivalent task hours per week [mMET-h/wk]) had 18% (95% CI, 13%-23%) lower risk of depression. Adults accumulating the recommended volume of 8.8 mMET hours per week had 25% (95% CI, 18%-32%) lower risk with diminishing potential benefits and higher uncertainty observed beyond that exposure level. There were diminishing additional potential benefits and greater uncertainty at higher volumes of physical activity. Based on an estimate of exposure prevalences among included cohorts, if less active adults had achieved the current physical activity recommendations, 11.5% (95% CI, 7.7%-15.4%) of depression cases could have been prevented.
This systematic review and meta-analysis of associations between physical activity and depression suggests significant mental health benefits from being physically active, even at levels below the public health recommendations. Health practitioners should therefore encourage any increase in physical activity to improve mental health.
Depression is a disorder characterised by persistent sadness and a lack of interest or pleasure in previously enjoyable activities. It is the leading cause of mental health-related disease burden, affecting approximately 1 in 20 adults worldwide. Reviews of the scientific evidence have shown that depression may be prevented by physical activity, but the benefits at different levels of activity are unclear. The aim of this study was to combine results from previously published studies to estimate the association between different levels of physical activity and depression.
We searched medical databases for studies including at least 3000 adults published up until 12th November 2020. The studies had to report the risk of developing depression for at least three different levels of physical activity. We included studies irrespective of how they measured physical activity. We standardised these measures to a common format so that the published results could be analysed together and make sense on the same physical activity scale. We estimated what proportion of depression cases would have been avoided if all adults in the studies met the current physical activity recommendations.
We included 15 studies with 191,130 participants and found that even small doses of physical activity appeared to substantially lower risks of depression. Adults meeting physical activity recommendations (equivalent to 2.5 hrs/week of brisk walking) had 25% lower risk of depression compared with adults reporting no physical activity. Our findings suggested that most benefits occurred when moving from no activity to at least some, and that only minor additional benefits were achieved by further increasing activity levels. Approximately 1 in 9 cases of depression might have been prevented if everybody in the population was active at the level of current health recommendations.