The effect of group-based lifestyle interventions on risk factors and insulin resistance in subjects at risk for metabolic syndrome: the Tabaruzaka Study 1.
The aim of this study was to evaluate the efficacy of two lifestyle interventions (4- and 10-month interventions) in improving insulin resistance and risk factors of metabolic syndrome. A total of 98 Japanese individuals who had at least one component of metabolic syndrome were randomized into standard intervention (SI) (4-month intervention, n=50) and extended intervention (EI) (10-month intervention, n=48) groups, and compared to a control group (n=39). Participants were evaluated after 10, 22 and 34 months. Results at month 10, just after EI, revealed that body mass index (BMI), HDL cholesterol, fasting plasma glucose (FPG) and glycated hemoglobin in both intervention groups were significantly improved. Moreover, trends toward a decrease in systolic blood pressure, diastolic blood pressure and triglycerides were observed in both intervention groups. At month 34, the effects on BMI and HDL cholesterol were sustained for both intervention groups and triglyceride levels were significantly decreased only in the EI group. Although fasting plasma glucose and mean number of metabolic syndrome components were not improved at month 34 compared to baseline levels, the increases in the control group from baseline to month 34 were significantly greater than those in both intervention groups. Whole-body insulin sensitivity index and hepatic insulin resistance index were also improved at month 10 in both lifestyle intervention groups. Thus, both lifestyle interventions improved the components of metabolic syndrome which support the promotion of lifestyle interventions to prevent metabolic syndrome.