Glycaemic control in people with diabetes influences the beneficial role of physical activity on cardiovascular mortality. Prospective data from the HUNT Study, Norway.

Aim: To examine whether glycaemic control in people with diabetes, measured as glycated haemoglobin (HbA1c), influences the role of leisure time physical activity on the increased risk of death from cardiovascular disease.

Methods: We prospectively examined the joint association of diabetes according to glycemic control, measured as glycated haemoglobin (HbA1c), and physical activity with cardiovascular mortality. A total of 53,549 were followed up for 12 years through the Norwegian Cause of Death Registry. Cox proportional adjusted hazard ratios (HRs) with 95% confidence intervals (CI) were estimated.

Results: Overall, 1710 people died from cardiovascular disease during the follow-up. Compared to the reference group of inactive people without diabetes, people with diabetes and HbA1c<8.0%, had a hazard ratio (HR) of 1.46 (95% CI: 0.96, 2.21) if they were physically inactive and a HR of 1.33 (95% CI: 0.81, 2.19) if they were physically active. Among people with diabetes and HbA1c ≥ 8.0%, the corresponding comparison gave HRs 2.69 (95% CI: 2.11, 3.42) and 0.93 (95% CI: 0.64, 1.36), respectively.

Conclusions: The data suggest that physical activity should be more strongly encouraged as a therapeutic measure additional to medical treatment, especially among those with most severe hyperglycemia.