Aerobic Exercise May Reduce Long-term T2D Risk in Persons with Obesity

A sustained 12-month program of moderate or vigorous aerobic exercise may support long-term prevention of type 2 diabetes (T2D) among persons with central adiposity, according to findings from a team of Chinese investigators published as a research letter in JAMA Internal Medicine on January 30, 2023.

Specifically, the investigators found the risk of T2D was reduced by approximately 50% over a 10-year follow up period among clinical trial participants who followed a vigorous or a moderate aerobic exercise plan vs those who did not engage in exercise.

It is now well known that lifestyle interventions that include dietary change and increased physical activity are effective for prevention of T2D, wrote lead author Xiaoying Li, MD, PhD, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China, and colleagues. Trials of such combined interventions have also included individual and/or group counseling. What hasn’t been studied, investigators stress, is the isolated effect of vigorous and moderate exercise on T2D prevention.

Li and colleagues previously conducted (between July 2021 and May 2022) a randomized controlled trial to evaluate long term effects of exercise alone on the prevention of T2D. For the original trial researchers randomized participants with central obesity and nonalcoholic fatty liver disease to either vigorous aerobic exercise (n=73), moderate aerobic exercise (n=73), or nonexercise control (n=74) groups.

At the end of the 12-month intervention, all participants were encouraged to continue following a healthy lifestyle and keep up with moderate intensity aerobic exercise.

Investigators followed up with participants at 2-year and 10-year visits to assess the incidence of T2D as well as change in body weight, waist circumference, and metabolic risk factors. For the study, incident diabetes was defined as fasting plasma glucose (FPG) ≥126 mg/dL, HbA1c ≥6.5%, and/or use of antihyperglycemic medication.

Of the original 220 study participants, 208 (94.5%) completed the 1-year exercise intervention. At the 2-year and 10-year follow-up visits, 195 (88.6%) and 179 participants (81.4%) continued with the assessment of incident diabetes, respectively.

FINDINGS

Li and colleagues report that while metabolic equivalents of leisure time physical activity among the 3 groups were similar at baseline, they were higher in the moderate and vigorous exercise groups than in the nonexercise group following the 1-year exercise intervention. At the 10-year follow-up, there were no significant differences among the 3 groups in physical activity but there was a trend of higher levels in the 2 intervention groups vs the control group.

Incidence of T2D at 10 years

Over 10 years of follow-up, the researchers found a cumulative incidence of T2D of 2.1 per 100 person-years (PYs) in the vigorous exercise group, compared to 1.9 per 100 PYs in the moderate exercise group, and 4.1 per 100 PYs in the nonexercise group.

When they compared the risk of T2D over 10 years in the nonexercise group with the 2 exercise intervention groups, the found a reduction of 49% (relative risk [RR], 0.51; 95% CI, 0.27-0.94; P=.01) in the vigorous aerobic exercise group and of 53% (RR, 0.47; 95% CI, 0.25-0.89; P=.01) in the moderate aerobic exercise group. The research team reported similar results of moderate and vigorous aerobic exercise in those who completed the original 12-month interventions.

Li et al also observed significant reductions in both HbA1c and waist circumference in the vigorous and moderate exercise groups compared with the nonexercise group. Finally, while FPG levels and weight regain were lower in the exercise intervention groups, there were no significant differences detected, the authors wrote.

“Regarding the importance of obesity management in the prevention of T2D addressed by the latest American Diabetes Association guideline,” the authors wrote in their discussion, “our results are supportive of physical exercise as an effective scheme for obesity management to delay the progression of T2D, and vigorous and moderate aerobic exercise programs could be implemented for prevention of T2D in people with obesity.”

Reference: Chen Y, Chen Z, Pan L, et al. Effect of moderate and vigorous aerobic exercise on incident diabetes in adults with obesity: a A 10-year fllow-up of a randomized clinical trial. JAMA Intern Med. Published online January 30, 2023.