In obese adults, a 12-month moderate-to-vigorous exercise program nearly halved the risk of type 2 diabetes over 10 years, according to the results of a new study analysis published as a research letter in JAMA. Internal Medicines.
In obese adults, a 12-month moderate-to-vigorous exercise program nearly halved the risk of type 2 diabetes over 10 years, according to the results of a new study analysis published as a research letter in JAMA Internal Medicine.
“Physical exercise combined with dietary restriction has been shown to be effective in preventing diabetes, however the long-term effect of training and the differences related to its intensity have not yet been investigated,” said the senior author Xiaoying Li dello Zhongshan Hospital, Fudan University, Shanghai.
The research team analyzed the results of a study involving 220 adults with obesity central and nonalcoholic fatty liver disease without diabetes, randomized to follow a 12-month program of vigorous exercise (73 patients), moderate aerobic exercise (73 patients), or no exercise (74 patients).
A total of 208 participants completed the program, of whom 195 and 178 continued to provide data at 2 and 10 years, respectively. The mean age was 53.9 years, 32.3% were male, and the mean waist circumference was 96.1 cm at baseline.
The cumulative incidence of the type 2 diabetes in the vigorous exercise, moderate exercise, and no exercise groups it was 2.1 per 100 person-years, 1.9 per 100 person-years, and 4.1 per 100 person-years, respectively, at 10-year follow-up. This translated into a reduction in type 2 diabetes risk of 49% in the intense exercise group and 53% in the moderate exercise group compared to the no exercise group.
Additionally, individuals in the vigorous and moderate exercise groups achieved significant reductions in glycated hemoglobin (HbA1c) levels and waist circumference compared with controls. Fasting blood glucose and weight regain were lower in the two exercise groups than in the non-athletes, but with nonsignificant differences.
A study started in 2016
The physical activity-based intervention was described in a 2016 study, which aimed to compare the effects ofexercise in patients with non-alcoholic fatty liver disease. Vigorous exercise included jogging for 150 minutes per week at 65%-80% of maximum heart rate for 6 months and brisk walking for 150 minutes per week at 45%-55% of maximum heart rate for another 6 months, while moderate it involved brisk walking for 150 minutes a week for 12 months.
Both exercise groups showed a trend toward higher levels of leisure-time physical activity after 10 years than the no-exercise groups, although the difference was not significant.
The major limitation of the study was that incident prediabetes was not prespecified, which may have led to some confounding data, the researchers noted. Additionally, participants were only highly supervised for a 12-month program. “In contrast, the results support the long-term value of exercise as a method for managing obesity and delaying the progression to type 2 diabetes in obese people,” they concluded. “Vigorous and moderate aerobic exercise programs could therefore be implemented for this patient population.”
Potential barriers to the routine use of an activity-based intervention in these patients include their reluctance to engage in strenuous exercise and the possible occurrence of musculoskeletal injury, Li said. In these cases, patients should be encouraged to exercise moderately. “More research is needed to evaluate the potential mechanism behind the effect of exercise on diabetes prevention.”
Important long-term data
“This study is important because it is based on long-term follow-up data and it is surprising to see the residual benefits of exercise after 10 years,” he commented. Jill Kanaley, interim chair of nutrition and exercise physiology at the University of Missouri. “We often wonder how long the impact of exercise training in weight control will last, and this study seems to indicate that there is an educational component that persists in patients.”
While this study was conducted in China, the findings could translate to a US population, he said. “However, our diet is often less healthy than the traditional Chinese one, which may have provided a huge benefit to the participants, even if they made no specific changes to their diet. More research is needed to confirm the findings and, ideally, should be repeated in a population on a Western diet.”
Compare maintaining or not exercising
Evidence on the long-term benefits of exercise programs is limited, she said in an interview Amanda Paluch, a physical activity epidemiologist at the University of Massachusetts, Amherst. “Chronic diseases like diabetes can take a long time to develop, so understanding these health outcomes requires years of follow-up. This study followed participants for 10 years and provides a nice overview of the long-term benefits of exercise training on diabetes prevention.”
“We cannot infer from these results whether the risk of diabetes was reduced by the 12-month exercise intervention or whether the benefit comes from maintaining regular physical activity over the 10-year follow-up period, or from a combination of the two,” he added. Future studies should consider subjects who were active only during the exercise intervention and ceased to be active versus those who maintained vigorous activity long-term.
References
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 Jan 30.
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