Year-long aerobic exercise intervention reduces long-term risk for diabetes

A 12-month aerobic exercise program reduced the risk for type 2 diabetes among people with central obesity over 10 years, according to a study published in JAMA Internal Medicine.

Ying Chen, MD, PhD, a postdoctoral researcher with the Ministry of Education Key Laboratory of Metabolism and Molecular Medicine at Zhongshan Hospital, Fudan University, in Shanghai, China, and colleagues wrote that lifestyle interventions such as diet and exercise are effective in preventing type 2 diabetes among high-risk individuals.

“However, the isolated effect of vigorous and moderate exercise on prevention of diabetes is uncertain,” they wrote. “We assessed the long-term effect of vigorous and moderate exercise on incident diabetes over a 10-year follow-up after a 12-month exercise intervention.”

The researchers based the follow-up study on a previous randomized clinical trial that evaluated the long-term impacts of exercise on the prevention of type 2 diabetes. The study consisted of patients with central obesity and nonalcoholic fatty liver disease who were assigned to one of three groups:

• vigorous aerobic exercise group;
• moderate aerobic exercise group; or
• non-exercise control.

All participants were told not to change their diet, and the exercise programs “were strictly coached and supervised,” the researchers wrote. They also encouraged all participants to continue with moderate intensity aerobic exercise and a healthy lifestyle and followed up at 2-year and 10-year visits to evaluate any changes that the intervention may have caused in body weight, metabolic risk factors and waist circumference.

Among the 179 participants who remained for assessment at the 10-year follow-up visit, Chen and colleagues found that the cumulative incidence of type 2 diabetes was 2.1 per 100 person-years in the vigorous group, 1.9 per 100 person-years in the moderate group and 4.1 per 100 person-years in the control group.

Compared with the non-exercise group, diabetes risk was reduced by:

• 49% (RR = 0.51; 95% CI, 0.27-0.94) in the vigorous aerobic exercise group; and
• 53% (RR = 0.47; 95% CI, 0.25-0.89) in the moderate aerobic exercise group.

“Likewise, similar results of moderate and vigorous aerobic exercise were observed in participants who completed 12-month intervention,” the researchers wrote.

Chen and colleagues also identified significant reductions in waist circumference and HbA1c in the intervention groups compared with the control group. Weight regain and fasting plasma glucose levels also appeared to be lower in the intervention groups, the researchers noted, but they did not observe any significant differences.

At baseline, the metabolic equivalents of leisure time physical activity were similar in the three groups, the researchers wrote, but were higher in the intervention groups at the end of follow up, although this finding was also not significant.

Chen and colleagues concluded that their findings “demonstrated that 12-month vigorous or moderate aerobic exercise programs could produce a long-term beneficial effect on diabetes prevention in individuals with central obesity.”

“Regarding the importance of obesity management in the prevention of type 2 diabetes addressed by the latest American Diabetes Association guideline, our results are supportive of physical exercise as an effective scheme for obesity management to delay the progression of type 2 diabetes, and vigorous and moderate aerobic exercise programs could be implemented for prevention of type 2 diabetes in people with obesity.”