Details of Publication 660 for Project A324:

van Uffelen J, Burton N, van Gellecum Y, Peeters G, Heesch K & Brown W. Concurrent and prospective associations between sitting time, physical activity and depression in mid-aged Australian women. , 2012; : 15(S6):28

Introduction: Physical activity (PA) can provide protective effects against depression, the relationship between sitting time and depression remains unclear. The aim of this study was to examine the concurrent and 9-year prospective associations between sitting time, PA and depression in mid-aged Australian women.Methods: Data were from 8,950 women, aged 50–55 in 2001, who completed surveys for the Australian Longitudinal Study on Women's Health in 2001, 2004, 2007 and 2010. Depression was assessed using the 10-item Center for Epidemiological Studies Depression questionnaire (CES-D, score =10 indicative of depression). A single question was used to measure hours/day spent sitting for work, leisure and travel. PA was assessed using adapted Active Australia questionnaire items about time spent walking and in moderate and vigorous activity; a PA score in MET.minutes/week was calculated and categorised. Associations between sitting (=4 hrs/day, >4–7 hrs/day, >7 hrs/day) and PA (none, insufficient, meeting guidelines) with depression (yes/no) were examined in concurrent and lagged mixed effect logistic models, adjusted for sociodemographic and health characteristics. As significant interactions between PA and sitting were found in some models, two models were computed to enhance comparability between results: a model including PA and sitting separately, and a model including a composite variable with the 9 combinations of PA and sitting.Results: In concurrent models, women doing insufficient or no PA were up to twice as likely to be depressed, and women sitting >4 hrs/day were up to one and a half times as likely to be depressed, compared with women meeting PA guidelines and women sitting =4 hrs/day, respectively. Models that explored combinations of PA and sitting showed that the risk of depression increased gradually, up to a tripled risk, in those doing no PA and sitting >7 hrs/day. In prospective models, women doing no PA were 25% more likely to be depressed at the next survey 3 years later, compared with women meeting guidelines, but sitting was not prospectively associated with depression. Models of combined effects confirmed that only women doing no PA had a significantly increased risk of depression.Discussion: Mid-aged Australian women not meeting PA guidelines and women who sit >4 hrs/day are more likely to be depressed. However, only women doing no PA have a greater risk of depression 3 years later. Based on these results, interventions in this population should focus on increasing PA in those who are physically inactive, in order to prevent future depression.