Clinical care and other categories posters: Epidemiology and genetics

Diurnal patterns of sedentary time and breaks in sedentary time predict intra-day glucose regulation in type 2 diabetes

AC Paing¹, KA McMillan^2,3, A Kirk², A Collier¹, A Hewitt², SFM Chastin^1,4

¹School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK, ²School of Psychological Sciences and Health, University of Strathclyde, Glasgow, UK, ³Department of Computer and Information Science, University of Strathclyde, Glasgow, UK, ⁴Department of Movement and Sports Science, Ghent University, Ghent, Belgium

Aim To evaluate diurnal patterns of sedentary time and breaks in sedentary time and their associations with pre-meal glucose, post-meal glucose, bedtime glucose, the dawn phenomenon and time in target glucose range (TIR, glucose 3.9–10mmol/l).

Methods This intensive longitudinal study included 37 adults with type 2 diabetes on diet modifications or metformin ± sulfonylurea ± gliptin (age, 62.8 ± 10.5 years; body mass index, 29.6 ± 6.8kg/m²). The FreeStyle Libre flash glucose monitoring system and activPAL3 were used to assess glucose and sedentary time (min/h) and breaks in sedentary time (n/h) in the morning, afternoon and evening for up to 14 days. Repeated measures ANOVA and regression analyses with generalised estimating equations approach were used.

Results Sedentary time was higher in the evening (43.47 ± 7.37min/h) than the morning (33.34 ± 8.44min/h, p < 0.001) and afternoon (37.26 ± 8.28min/h, p < 0.001). In contrast, breaks in sedentary time were lower in the evening (2.64 ± 0.74n/h) than the morning (3.69 ± 1.08n/h, p < 0.001) and afternoon (3.06 ± 0.87n/h, p < 0.001). Sedentary time in the morning was significantly associated with the increased dawn phenomenon. Sedentary time in the evening was significantly associated with increased pre-breakfast glucose, pre-lunch glucose, post-breakfast glucose, post-lunch glucose, post-dinner glucose, bedtime glucose and the dawn phenomenon and reduced TIR. Breaks in sedentary time in the morning and evening were significantly associated with increased TIR.

Conclusions Prolonged uninterrupted sedentary behaviour is higher in the evening and could be an important predictor of intra-day glucose regulation. Interventions targeting sedentary behaviour, especially in the evening, may be beneficial for glucose control.