Prevention of Metabolic Syndrome by Telephone-Delivered Lifestyle Intervention in a Real-World Setting: Sub-Analysis of a Cluster-Randomized Trial.

Evidence of the long-term benefits of telephone-delivered lifestyle interventions is limited. This study investigated the ability of telephone-delivered lifestyle intervention to reduce the incidence of metabolic syndrome (MetS) in subjects diagnosed with impaired fasting glucose (IFG) during health checkups. Our subjects were participants in the Japan Diabetes Outcome Intervention Trial-1 (J-DOIT1), a prospective, cluster-randomized controlled trial designed to investigate whether goal-focused lifestyle coaching over the telephone can effectively reduce the incidence of type 2 diabetes development in high-risk individuals in a primary health care setting. We extracted 753 and 844 J-DOIT1 participants from the intervention and controls arms, respectively, who had IFG but did not meet the MetS criteria at baseline. The intervention arm received goal-focused lifestyle support delivered by health care providers via telephone over a 1-year period. The endpoint was the development of incident MetS, defined based on the Adult Treatment Panel III criteria modified for Japan. During the median follow-up period of 4.9 years, 8.0% of the intervention arm and 12.0% of the control arm developed MetS. Overall, the hazard ratio (HR) for the development of MetS was 0.75 [95% confidence interval (CI), 0.52-1.09;  = 0.14] in the intervention arm. However, the HR in overweight or obese [body mass index (BMI) ≥23 kg/m] individuals was significantly reduced to 0.63 (95% CI, 0.41-0.95;  = 0.029), but not in lean (BMI <23 kg/m) individuals. Telephone-delivered lifestyle intervention effectively reduced the incidence of MetS in overweight and obese subjects in a real-world setting. Clinical trial registration number: UMIN000000662 (registered March 30, 2007; https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000000798).