Massive Review Correlates Exercise with Reduced Diabetes Risk

A large new meta-analysis has examined the connection between exercise and the likelihood of developing type 2 diabetes, and it has come to a simple conclusion: the more exercise, the greater the risk reduction.

The meta-analysis used data from 28 prior research efforts conducted around the globe, and it included data on 1.26 million people and 84,134 new cases of diabetes. Cohort sizes ranged from 916 people to 675,496 people, with cumulative type 2 diabetes incidence ranging from 1.6% to 27.5%. Follow-up time varied from 3 to 23.1 years.

After harmonizing data and controlling for numerous factors, analysis of study results found that virtually any exercise reduces the risk of incident diabetes and that the level of protection keeps on going up along with the amount of exercise, though not in a linear fashion. Using the cubic spline model to estimate protective effects, the investigators found a risk reduction of 26% for type 2 diabetes among those who achieved 11.25 metabolic equivalent of task (MET) hours per week (equivalent to 150 min/week of moderate activity) rather than undertaking no exercise. Achieving twice this amount of physical activity was associated with a risk reduction of 36%, with further reductions at higher doses. Exercise equivalent to 60 MET h/week reduced the risk of incident diabetes by 53%.

“These new results add more detail to our understanding of how changes in the levels of physical activity across populations could impact the incidence of disease. They also lend support to policies to increase physical activity at all levels. This means building environments that make physical activity part of everyday life,” said co-author Soren Brage, PhD, a program leader for the Medical Research Council Epidemiology Unit at Cambridge University.

Brage and his colleagues noted that levels of physical activity recommended by many government agencies around the globe provide relatively little protection against type 2 diabetes. The official recommendation for the United Kingdom, for example, is for people to try for the 150 minutes of weekly exercise that only reduces risk by 26%.

“Our results suggest that the benefits of higher activity levels extend considerably beyond the minimum recommendations. Using the restricted cubic spline model we found that a doubling of activity volume from 11.25 MET h/week to 22.5 MET h/week would further reduce the risk of type 2 diabetes by 10% to a total risk reduction of 36% compared with being inactive,” the study authors wrote in Diabetologia.

They went on to note a number of strengths in their meta-analysis, must notably the size of the cohort, the degree to which they were able to homogenize the data from various component studies and the specificity with which they were able to draw the curve linking exercise duration and risk reduction.

As for weaknesses, they noted that many of the cohorts were not specifically designed to assess the relationship between physical activity and incident diabetes. They also noted that the cohorts for most studies were overwhelmingly white and that different populations might need different amounts of exercise to achieve the same protective effects.

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