Replacement of sedentary behavior with various physical activities and the risk of incident depression: a prospective analysis of accelerator-measured and self-reported UK Biobank data.

Abstract

To examine the dose‒response relationships of sedentary behavior (SB) and physical activities (PAs) with depression, and to explore the effects of replacing SB with PAs on depression risk. The study used data from UK Biobank aged 37 to 73 years. Light physical activity (LPA), moderate-to-vigorous activity (MVPA), sleep duration, and total sedentary behavior (TSB) were measured by accelerometers. Self-reported SB was also adopted when daily screen-sedentary behavior time (SSB) and leisure-sedentary behavior time (LSB) were the focus. Incident depression was obtained from the part of mental and behavioral disorders in the "first occurrence fields" of UK Biobank. A Cox proportional hazard model and isotemporal substitution model were performed to explore the associations of LPA, MVPA, TSB, LSB, SSB, and sleep on depression and the effects of replacing SB time with equal PA time. Highest levels of MVPA (HR = 0.58, 95%CI: 0.50-0.68) were associated with decreased depression risk compared with the lowest level (Q1). Longer SSB time (HR = 1.18, 95%CI: 1.06-1.32), LSB time (HR = 1.19, 95%CI: 1.07-1.32), and TSB time (HR = 1.17, 95%CI: 1.00-1.38) could increase depression risk significantly. Replacing 1h/day TSB, SSB, and LSB with MVPA brought the greatest risk reductions [31% (HR = 0.69, 95%CI: 0.62-0.77), 30% (HR = 0.70, 95%CI: 0.65-0.77), and 29% (HR = 0.71, 95%CI: 0.65-0.77)]. Under the same conditions, the effects of LPA replacement were also significant, but weaker than those of MVPA. Subgroup analyses showed that replacing 1h/d TSB with LPA could significantly decrease the depression risk for the females, but not for the males. Large benefits for reducing the risk of incident depression could be attained by replacing a period of TSB, SSB, or LSB with equal PA time, especially for MVPA. Regular PA and less SB were recommended for improving mental health.