Sedentary behavior and depression among community-dwelling adults aged >= 50 years: Results from the irish longitudinal study on Ageing

Background: : Sedentary behavior (SB) may be a risk factor for depression in middle- and old age adults. The aim of this study was to examine cross-sectional and longitudinal relationships between SB and depression in a large national sample of Irish people aged 50 and older taking into account a wide range of previously identified influential factors. Methods: : Data from the Irish Longitudinal Study on Ageing survey were analyzed (wave 1: 2009-2011, wave 2: 2012-2013). Depression was assessed with the Center for Epidemiologic Studies Depression scale. Total weekday SB and control variables were self-reported. Multivariable logistic regression and mediation analysis were conducted to assess the associations. Results: : The final sample consisted of 6903 individuals aged >= 50 years (63.6 +/- 9.2 years; 52.1% female). After full adjustment for age, gender, social class, current smoking, physical activity, mobility, pain, cognition, chronic physical conditions, disability, anxiety, loneliness, and social network, the association between SB and depression was not statistically significant (OR =1.06; 95%CI = 0.60-1.89). Mediation analysis showed that the association is explained by social network (mediated percentage 23.1%), physical activity (20.3%), loneliness (13.2%), chronic physical conditions (11.1%), and disability (7.9%). Cross-sectional analysis showed that SB is significantly associated with depression even after full adjustment. Limitations: : SB was self-reported. Conclusions: : Factors closely linked with SB such as social isolation, loneliness, physical inactivity, chronic physical conditions, and disability may play a major role in depression among middle-aged and older people. Lifestyle interventions focusing on reductions in depression in this population need to consider these factors.