Background/objectives: Exercise is considered a protective factor in the prevention of type 2 diabetes, although its role as a sole treatment for pre-diabetes remains unknown. The present meta-analysis compared the effect of exercise-only with exercise-diet interventions on plasma glucose levels among a pre-diabetic population.
Subjects/methods: A literature search was conducted using PubMed, EMBASE and Cochrane databases. The Cochrane Collaboration tool was used to assess the quality of each trial. Two reviewers independently performed quality assessment of all included articles. A random effects model was used to calculate the pooled effect.
Results: A total of 4021 participants from 12 studies were included in this meta-analysis, 2045 of them were in the intervention group and 1976 were in the control group. Compared with the exercise-only interventions, the exercise-diet interventions showed a significant effect on decreasing fasting plasma glucose (FPG) levels, with a weighted mean difference (WMD) =-0.22 mmol/l, 95% confidence interval (CI): -0.25, -0.18 (Z=12.06, P<0.05). The subgroup effect of exercise-only interventions did not produce a statistically significant result (WMD=-0.09 mmol/l, 95% CI: -0.18, 0.00, Z=1.91, P>0.05). According to the intervention periods, the pooled effect in the ⩾2-year group was the highest, and its WMD (95% CI) was -0.24 mmol/l (-0.43,-0.05). The pooled effects were statistically significant among the elderly and those of American and European descent, with WMD (95% CI) being -0.19 mmol/l (95% CI: -0.22, -0.15), -0.17 mmol/l (-0.21,-0.12) and -0.22 mmol/l (-0.27, -0.17), respectively.
Conclusions: Evidence from published trials indicates that exercise-diet interventions showed a significant effect on decreasing FPG levels.