The mediating and interacting role of physical activity and sedentary behavior between diabetes and depression in people with obesity in United States

Sufficient physical activity (PA) and less sedentary behavior (SB) have antidepressant effects, however the amount of PA varies according to weight status in adults with diabetes. Given that depression is a common complication of diabetes, we aimed to quantify to what extent the effects of diabetes on the risk of depression were explained by SB or insufficient PA in adults with and without obesity.Data were collected from the 2007-2016 National Health and Nutrition Examination Survey (NHANES), which included 22,304 participants aged 20 years or older. The mediation and interaction were evaluated by the four-way effect decomposition method.In individuals suffering from obesity, diabetes, SB, and insufficient moderate and vigorous intensity recreational activity were associated with an increased risk of depression. The increased relative risk of diabetes on depression could be decomposed into a reference interaction (96.78%), a mediated interaction (5.07%), and a pure indirect effect (2.48%), with insufficient moderate-intensity recreational activity as a potential mediator. SB attributed a proportion of 89.21% for the controlled direct effect and 3.64% for pure indirect effect.Adults with obesity and diabetes are encouraged to increase moderate-intensity recreational activity and reduce SB, which can greatly prevent the occurrence of depression.