Impact of objectively measured sedentary behaviour on changes in insulin resistance and secretion over 3 years in the...

The importance of reducing sedentary time is increasingly being recognized in the prevention of diabetes and cardiovascular disease. Despite this, the prospective association between sedentary time and physical activity with insulin sensitivity and cardiometabolic risk factors has been little studied.

In an analysis of data from the European RISC study, sedentary time and time spent in activity of moderate or vigorous intensity were assessed by accelerometry at baseline in 313 men and 414 women, aged 30-60 years, with insulin sensitivity as measured by euglycaemic-hyperinsulinaemic clamp. Three years later, cardiometabolic risk factors (anthropometry, glucose, insulin, lipids) were available for 549 participants.

In cross-sectional analyses using baseline data, after adjusting for age, gender, recruitment centre and time spent in activity of moderate or vigorous intensity, significant unfavourable associations were observed between higher sedentary time with body weight, HDL cholesterol, triglycerides, clamp-measured insulin sensitivity and insulin secretion (all P(trend)<0.002). Sedentary time remained significantly associated with insulin secretion after adjusting for insulin sensitivity (P(trend)=0.02). In longitudinal analyses, higher baseline sedentary time was associated with 3-year increases in fasting glucose, fasting insulin and the HOMA insulin-resistance index score for the 50% of the study population who increased their BMI by at least 0.3 kg/m(2) (all P(trend)<0.01); these relationships remained significant after adjusting for time spent in activity of moderate or vigorous intensity. The 3-year increase in insulin secretion was lower in those spending more time doing activity of moderate or vigorous intensity (P(trend)=0.03).

These prospective data suggest that less sedentary behaviour may partly counteract some of the negative effects of increasing body weight on glucose-insulin homoeostasis.