Association between device measured and self-reported sitting in relation to depression: the 1970 British Cohort Study

Aims While physical activity appears to confer protection against depression, the relationship between sedentary behaviour and mental health is uncertain. Self-reported methods provide information about context although there may be error in the quantification of sedentary behaviour. Accordingly, we examined associations of both device-measured and self-reported sedentary behaviour with depression. Method Participants (n=4,704; 52.4% Female; aged 46-48) were drawn from the 1970 British Cohort Study. Sitting time and moderate-vigorous physical activity was measured using a thigh-worn accelerometer device (ActivPAL) over a seven day period. A range of self-reported sedentary behaviours was measured to provide context. Depression diagnosis was captured using a combination of self-reported consultation with a physician and use of anti-depressant medication. Malaise inventory was used to assess depressive symptoms. Results Relative to those who spent 10 hr/d) had increased odds of depression diagnosis (odds ratio= 1.48 [95% confidence interval 1.05-2.08]). There was no association between self-reported TV viewing and depression diagnosis (1.07; 0.71-1.63). We observed protective associations between moderate-vigorous physical activity and depression diagnosis (highest tertile vs. the lowest tertile; 0.70;0.49-1.00). Associations of sitting time and physical activity with depression were mutually independent. Relative to 3 hours of internet weekday usage were associated with increased odds of depressive symptoms (1.60;1.30-1.97 and 1.63;1.32-2.03, respectively). Conclusion Device-measured sitting is associated depression diagnosis, although less consistent associations are observed with self-reported sedentary behaviours. Regular physical activity and reducing sedentary time may be beneficial for prevention of depression.