Abstract Aims/hypothesis Weexaminedtheassociationbetweensitting time and diabetes incidence, overall and by strata of leisuretime physical activity and BMI. Methods We followed 28,051 adult participants of the NordTrøndelag Health Study (the HUNT Study), a populationbased study, for diabetes incidence from 1995–1997 to 2006–2008 and estimated HRs of any diabetes by categories of self-reported total daily sitting time at baseline. Results Of 28,051 participants, 1253 (4.5%) developed diabetes during 11 years of follow-up. Overall, sitting ≥8 h/day was associated with a 17% (95% CI 2, 34) higher risk of developing diabetes compared with sitting ≤4 h/day, adjusted for age, sex and education. However, the association was attenuated to a non-significant 9% (95% CI −5, 26) increase in risk after adjustment for leisure-time physical activity and BMI. The association between sitting time and diabetes risk differed by leisure-time physical activity (pInteraction=0.01). Among participants with low leisure-time physical activity (≤2 h light activity per week and no vigorous activity), sitting 5–7 h/day and ≥8 h/day were associated with a 26% (95% CI 2,57)and30%(95%CI5,61)higherriskofdiabetes,respectively, compared with sitting ≤4 h/day. There was no corresponding association among participants with high leisuretime physical activity (≥3 h light activity or >0 h vigorous activity per week). There was no statistical evidence that the association between sitting time and diabetes risk differed by obesity (pInteraction=0.65). Conclusions/interpretation Ourfindingssuggestthattotalsitting time has little association with diabetes risk in the population as a whole, but prolonged sitting may contribute to an increased diabetes risk among physically inactive people.
Keywords Epidemiology .Sedentarylifestyle .Type2 diabetesmellitus