Cross-Sectional Associations Between Sitting Time and Several Aspects of Mental Health in Belgian Adults

Background: Sedentary behavior (including sitting) is negatively associated with physical health, independent from physical activity (PA). Knowledge on the associations with mental health is less elaborated. Therefore this study aims to investigate the relationship between sitting and 5 indices of mental health in adults (psychological distress, depression, anxiety, somatization, and sleeping problems), and between sitting interactions (sittingxgender, sittingxage, sittingxeducation, and sittingxPA) and these mental health indices. Methods: A cohort of Belgian adults (25-64 years; n = 4344) provided self-reported data on sitting and PA and on 5 mental health indices. Cross-sectional associations were examined using multiple linear regression analyses. Results: Analyses adjusted for gender, age, education, and PA showed significant positive associations between sitting and the 5 mental health indices (P<.05). All associations were true for both men and women, and for low and high educated individuals, while some were only found in older individuals (somatization, P<.001) and those being insufficiently active (psychological distress, P=.007; depression, P=.002; and anxiety, P=.014). Conclusions: More sitting seems to be associated with poorer mental health, independently of gender, age, education, and PA. Moderation analyses showed that these associations may differ according to age and PA levels.