Depression is the leading cause of mental health–related disease burden and a major cause of disability worldwide. In addition to the suicide risk, depression is associated with premature mortality from other illnesses, in particular, from cardiovascular events. Prevention of depression requires effective interventions, including modification of established risk factors. There is a growing body of evidence suggesting that physical activity can prevent future depression. However, estimating the dose-response relationship between physical activity and any health outcome using meta-analysis is challenging because of the diversity of assessment and inconsistent reporting. Most often, the harmonization of different estimates of physical activity exposure is achieved using binary categorization of low vs high activity, but this approach results in loss of information and does not tell us about the variation in risk across a range of physical activity doses. On April 13, 2022, a new meta-analysis appeared online in JAMA Psychiatry focusing on the dose-response association between physical activity and incident depression based on prospective studies of adults. This meta-analysis 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.
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 greater differences in risk at lower activity levels. 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.
Reference: https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2790780
