Associations of Objectively Measured Sedentary Time and Breaks in Sedentary Time With Cardio-Metabolic Markers in a High Risk UK Population

Purpose Sedentary behaviour is known to have a detrimental effect on health. However, the manner in which is it accumulated may also be important. Therefore, we examined the association of daily sedentary time and breaks in sedentary time with various markers of cardio-metabolic risk.

Methods Cross-sectional analysis using 725 participants from the ongoing Walking Away from Diabetes study. Sedentary time (<100 counts/min) was measured using Actigraph GT3X accelerometers (15-s epochs), worn during waking hours for 7 consecutive days. A break was considered as an interruption in sedentary time (>100 counts/min). Linear regression analysis examined the association of sedentary time and breaks with markers of metabolic (2-hr glucose, waist circumference, BMI) and cardiovascular health (triglycerides, HDL cholesterol).

Results Of the 725 individuals included, 470 (64.8%) were male and average age (±SD) was 63.7±7.8 years. Accelerometer wear time was 14.4±1.4 hours per day, of which 10.3±1.5 hours (71.5%) was spent sedentary. Sedentary time was broken, on average 273±60 times per day. Following adjustment for various covariates (including physical activity and BMI) there were significant detrimental linear associations of total sedentary time with 2-hr glucose (ß=0.269, SE=0.066, p≤0.001), waist circumference (ß=0.139, SE=0.060, p≤0.05), HDL cholesterol (ß=-0.131, SE=0.060, p≤0.05) and triglycerides (ß=0.160, SE=0.064, p≤0.05). Breaks in sedentary behaviour were significantly inversely associated with 2-hr glucose (ß=-0.119, SE=0.058, p≤0.05), waist circumference (ß=-0.213, SE=0.052, p≤0.001) and BMI (ß=-0.136, SE=0.048, p≤0.05), independent of sedentary time and adiposity.

Conclusions This large population based dataset suggests that individuals at high risk of T2DM would benefit from reducing total sedentary time by increasing the number of breaks.