Continued moderate or vigorous exercise over a 10-year period is associated with a significantly reduced risk of incident type 2 diabetes
Participants who continued to exercise for up to 10 years following completion of a 12 month randomised trial, had a significantly lower risk of developing incident type 2 diabetes according to the findings of a study by Chinese researchers.
Globally, type 2 diabetes affects around 462 million people or just over 6% of the entire population. Lifestyle modifications such as diet or increased exercise are known to reduce the risk of developing the disease. However, most of the available evidence for effects of lifestyle modification has been derived from high-risk individuals, for instance, those with elevated fasting glucose levels, or those who are both overweight and having impaired glucose tolerance. A further problem is that many of these intervention studies were of a relatively short duration. It is therefore less unclear whether maintenance of lifestyle modifications such as increased physical activity, over the longer term, still reduces the risk of developing T2D.
In the current study, Chinese researchers reported the longer term outcomes of a 12 month randomised trial they had undertaken. In the original trial, participants with non-alcoholic fatty liver disease, were randomised to vigorous to moderate physical activity, moderate exercise (brisk walking) or no exercise for 12 months. The results of the trial showed that both forms of exercise were effective at reducing intrahepatic triglyceride levels compared to those who did not exercise.
Following the trial, the majority of the study participants were followed-up after 2 and 10 years to assess the incidence of T2D, defined as a fasting plasma glucose of 6.9 mmol/L and a HBA1c of > 6.5% and or the use of anti-diabetic treatment.
Continued exercise and incident type 2 diabetes
From an original cohort of 208 participants who completed the year long trial, 195 and 179 remained for subsequent assessment after 2 and 10 years respectively.
The cumulative incidence of T2D was 2.1 per 100 person-years, 1.9 and 4.1 in those who continued with vigorous, moderate or no exercise respectively. In fact, the risk of T2D was reduced by 49% among those performing vigorous exercise (relative risk, RR = 0.51, 95% CI 0.27 – 0.94, p = 0.01) and by 53% among moderate level intensity exercise (RR = 0.47, 95% CI 0.25 – 0.89, p = 0.01) compared to the non-exercising group.
While both exercise groups had significant reductions in HBA1c levels compared to non-exercisers during the follow-up period, fasting plasma glucose levels while numerically lower in the two exercising groups than the non-exercise control group, these differences were non-significant.
The authors suggested that vigorous to moderate aerobic physical activity could be used to prevent T2D, particularly in those with obesity.
Chen Y et al. Effect of Moderate and Vigorous Aerobic Exercise on Incident Diabetes in Adults With Obesity: A 10-Year Follow-up of a Randomized Clinical Trial. JAMA Intern Med 2023