Replacement of Sedentary Behavior by Various Daily-Life Physical Activities and Structured Exercises: Genetic Risk and Incident Type 2 Diabetes.

<bold>Objective: </bold>To prospectively analyze the association of sedentary behavior time with type 2 diabetes (T2D) risk and perform the isotemporal substitution analyses to estimate the effect of substitution of sedentary behaviors by equal time of different types of daily-life physical activities and structured exercise. We also examined modifications by the genetic predisposition to T2D.<bold>Research Design and Methods: </bold>We included 475,502 participants free of T2D in the UK Biobank. Sedentary time was quantified by summing up the time spent on television watching, computer use, and driving.<bold>Results: </bold>During a median follow-up of 11 years, we documented 18,169 incident T2D cases. In comparison of the extreme categories (≥6 vs. <2 h/day), the hazard ratio for T2D was 1.58 (95% CI 1.47, 1.71) after adjustment for age, race, sex, lifestyle factors, and other covariates. Replacing 30 min of sedentary behavior per day with an equal amount of time of different types of daily-life activities and structured exercise was significantly associated with a 6-31% risk reduction of T2D, with strenuous sports showing the strongest (31%, 95% CI 24, 37) benefit. Moreover, we found a significant interaction between sedentary behavior and genetic predisposition for the risk of T2D (Pinteraction = 0.0008). The association was more profound among participants with a lower genetic risk of T2D.<bold>Conclusions: </bold>Our study indicates that sedentary behavior time is associated with an increased risk of T2D; replacing sedentary behavior with a short duration (30 min/day) of daily-life physical activities or structured exercise is related to a significant reduction in T2D risk. Furthermore, such association was stronger among those with a lower genetic risk of T2D. [ABSTRACT FROM AUTHOR]