Sitting time, fidgeting and all-cause mortality in the UK Women's Cohort Study

Introduction: Sedentary behaviours (including sitting) may increase risk of mortality independently of physical activity level. Little is known about how fidgeting behaviours might modify the association. Methods: Data were drawn from the UK Women’s Cohort Study. In 1999/2002, 12,778 women (age 37 to 78) provided data on average daily sitting time, overall fidgeting (irrespective of posture), and a range of relevant covariates including physical activity, diet, smoking status and alcohol consumption. Participants were followed for mortality over a mean of 12 years. Proportional hazards Cox regression models were used to estimate the relative risk of mortality in the high (vs. low) and medium (vs. low) sitting time groups. Results: Fidgeting modified the risk associated with sitting time (p value for interaction = 0.04), leading us to separate groups for analysis. Adjusting for a range of covariates, sitting for 7+ hours/day (vs.