van Uffelen JGZ et al. – The study aims to examine concurrent and prospective associations between both sitting–time and physical activity with prevalent depressive symptoms in mid–aged Australian women. Increasing physical activity to a level commensurate with guidelines can alleviate current depression symptoms and prevent future symptoms in mid–aged women. Reducing sitting–time may ameliorate current symptoms.
- Data were from 8950 women, aged 50–55 years in 2001, who completed mail surveys in 2001, 2004, 2007, and 2010.
- Depressive symptoms were assessed using the Center for Epidemiological Studies Depression questionnaire.
- Associations between sitting-time (≤4 hours/day, >4–7 hours/day, >7 hours/day) and physical activity (none, some, meeting guidelines) with depressive symptoms (symptoms/no symptoms) were examined in 2011 in concurrent and lagged mixed-effect logistic modeling.
- Both main effects and interaction models were developed.
- In main effects modeling, women who sat >7 hours/day (OR=1.47, 95% CI=1.29, 1.67) and women who did no physical activity (OR=1.99, 95% CI=1.75, 2.27) were more likely to have depressive symptoms than women who sat ≤4 hours/day and who met physical activity guidelines, respectively.
- In interaction modeling, the likelihood of depressive symptoms in women who sat >7 hours/day and did no physical activity was triple that of women who sat ≤4 hours/day and met physical activity guidelines (OR 2.96, 95% CI=2.37, 3.69).
- In prospective main effects and interaction modeling, sitting-time was not associated with depressive symptoms, but women who did no physical activity were more likely than those who met physical activity guidelines to have future depressive symptoms (OR=1.26, 95% CI=1.08, 1.47).