Prospective relationships of sedentary behaviors with incident depression and potential biological mediators

Abstract

Abstract Sedentary behavior (SB) is associated with depression, yet little is known about the relationship between different types of SB (e.g., passive versus mentally-active) with depression and potential biological mediators of these associations. We used cohort data from the 1958 National Child Development Study (n = 4,607;50.4% women), employing the 44y wave as baseline, and the 46y, 50y and 55y waves as follow-up. TV-viewing and watching videos (i.e., passive SB), and time sitting while doing light activities such as deskwork or driving a car during worktime (i.e., mentally-active SB) were self-reported by participants. Depression diagnosis was self-reported during the initial and follow-up waves and the participants answered the CIS-R at 44y. Waist circumference, C-reactive protein, and glycated hemoglobin were assessed at baseline and examined as potential mediators. We created Cox proportional hazards regression models, adjusting for gender, education, employment status, physical activity, tobacco smoking, and alcohol consumption at baseline. There were 636 cases of incident depression over 47,184 person-years. Passive SB was associated with higher hazards of incident depression (HR: 1.43; 95%CI: 1.19–1.71), while there was no association with mentally-active SB. Waist circumference (coefficient: -0.03; 95%CI: -0.05; -0.01; 9.2%) and C-reactive protein (coefficient: -0.03; 95%CI: -0.04; -0.01; 8.3%), but not glycated hemoglobin, partly mediated the association with passive SB. Higher durations of time spent in mentally-passive SB can increase risk of incident depression. The mediating contributions of waist circumference and C-reactive protein point to possible inflammatory-related mechanisms and suggest potential benefits of jointly addressing metabolic and mental health.