Effects of aerobic exercise on adiponectin levels potentially mediated by vitamin D in type 2 diabetic patients

Objective. The positive effects of exercise on adiponectin and vitamin D have independently been reported. Recent studies have suggested that vitamin D increases adiponectin synthesis through inhibition of the rennin-angiotensin system in adipose tissue. However, studies evaluating the effects of an aerobic exercise on adiponectin and vitamin D simultaneously investigating the potential mechanism of vitamin D-dependent adiponectin pathways in patients with type 2 diabetes mellitus (T2DM) are still limited. This study was undertaken to examine the effects of aerobic exercise on adiponectin and its association with vitamin D in patients with T2DM. Methods. Total twenty-two patients with T2DM were randomly divided into intervention and control group. The intervention group underwent a moderate intensity of a walking mode treadmill aerobic exercise for four weeks. The exercise protocol was adapted from modified Bruce test with a periodic speed and inclination increase. In both groups, body mass index (BMI), vitamin D, and adiponectin levels, were measured before and after four weeks of the lasting program. Results. The mean of the increased adiponectin and vitamin D levels after exercise was significantly higher in the intervened than the control group, but statistically significant difference was only found in the adiponectin effect (p=0.017). There was a significant association found between vitamin D and adiponectin in the intervention group after data adjustments to age and BMI (p=0.005). Conclusion. Moderate intensity of treadmill exercise with increased speed and inclination periodically increased adiponectin level in patients with T2DM. The increased adiponectin might potentially be mediated by increased vitamin D, but the level of their association impact was dependent on the age and BMI.