Sedentary time and depressive symptoms in adults: Exploring moderators

Purpose: To examine the associations of weekday and weekend day sedentary time with depressive symptoms and explore employment status and demographic variables as moderators.

Methods: Participants (N = 884; Mean age = 46.0 SD 10.5) were recruited from neighborhoods varying by walkability and income. Participants wore Actigraph accelerometers for 7 days. Daily average sedentary time (counts per minute <100 ) was calculated for weekdays and weekend days. Sedentary minutes were dichotomized as 8+ hours or <8 hours/day. Participants completed a measure of depressive symptoms (CES-D) which was dichotomized to reflect whether they had mild to moderate depressive symptoms (>10 points) or not. Generalized linear mixed models assessed interaction effects between depressive symptoms and sedentary time by work status and other demographic variables, adjusting for neighborhood clustering, study region, vehicle ownership, physical activity, and BMI.

Results: Weekend sedentary time and depression were not related. There was a significant negative relationship for weekday sedentary time and a significant (p<.01) three way interaction between sedentary time, marital status, and employment status. Those averaging 8+ hours of weekday sedentary time who worked but were not married were significantly less likely to be depressed (OR =0.52, p=.002). The relationship between sedentary time and depression was not significant but was positive (OR=1.2) in married workers.

Conclusions: Some studies have shown that sedentary behavior may be related to poorer mental health. In this diverse adult population sample, however, a sedentary working life was related to fewer depressive symptoms in those who were not married.