Effects of physical activity on the development and progression of microvascular complications in type 1 diabetes: retrospective analysis of the DCCT study

Background: To examine the effects of physical activity on the development and progression of microvascular complications in patients with type 1 diabetes. Methods: A retrospective analysis of data from the Diabetes Control and Complications trial was undertaken. Physical activity data was collected at baseline for each of 1441 recruits, converted to metabolic equivalent of task values, and categorised according to the American College of Sports Medicine recommendations. The rates of development/progression of diabetic retinopathy, nephropathy and neuropathy were compared in those who achieved over twice recommended, up to twice recommended, and less than recommended metabolic equivalent of task levels of activity. The DCCT study had a mean duration of follow up of 6.5 years ending in 1993. Results: A total of 271 subjects had a sustained three-step progression in diabetic retinopathy. The rates of development or progression of retinopathy showed no significant association with physical activity level. The number of outcomes for nephropathy and neuropathy were small and there was no significant association with physical activity level. Conclusions: We found no evidence that physical activity improves microvascular outcomes in type 1 diabetes. However we demonstrate no evidence of harm. We suggest that physical activity continues to play an important role in the management of type 1 diabetes.