Longitudinal effects of a nationwide lifestyle intervention program on cardiometabolic outcomes in Japan: An observational cohort study.

The Japanese government launched a nationwide health screening and lifestyle intervention program in 2008 to prevent and reduce metabolic syndrome in at-risk individuals. This study examined the longitudinal effects of the program's lifestyle interventions on metabolic outcomes using health insurance data from one prefecture. The study population comprised 16,317 individuals aged 40-74 years who met the recommendation criteria for the interventions between 2009 and 2015. Participants were categorized into an overall intervention group (comprising a single-session motivational intervention group and a multi-session intensive intervention group) and a non-intervention group. We evaluated the interventions' effects on the initiation of medications for metabolic disorders (hyperlipidemia, hypertension, and hyperglycemia) and metabolic syndrome incidence for 6 years using discrete hazard models that adjusted for sex, age, health screening measurements, and smoking habit. The longitudinal effects on health screening measurements were also evaluated using regression models for repeated measures. The adjusted hazard ratios (aHRs) (95% confidence interval [CI]) for initiation of medications were 0.83 (0.77-0.90), 0.77 (0.71-0.84), and 0.66 (0.57-0.77) for overall, motivational, and intensive interventions, respectively. The aHRs (95%CI) for metabolic syndrome incidence were 0.84 (0.75-0.94), 0.80 (0.71-0.91), and 0.67 (0.51-0.89) for overall, motivational, and intensive interventions, respectively. The interventions reduced body mass index and waist circumference, but had modest effects on blood lipids, blood glucose, and hemoglobin A1c levels; blood pressure was unaffected. These interventions represent an effective strategy to prevent the progression of preclinical metabolic syndrome, but further studies are needed to evaluate their long-term preventive effects on cardiovascular disease and diabetes.