Impact of Metabolic Syndrome on the Mortality Rate among Participants in a Specific Health Check and Guidance Program in Japan

Objective In Japan, the Specific Health Check and Guidance (Tokutei-Kenshin) program was started in 2008 to decrease the social burden related to metabolic syndrome (MetS). However, so far this program has not been found to have any impact on the mortality rate. Methods The subjects consisted of individuals who participated in the Tokutei-Kenshin in seven districts between 2008 and 2015. Using a National database of death certificates, we identified those who might have died and then further confirmed such deaths with the collaboration of the regional National Health Insurance agency and public health nurses. The diagnosis of MetS was made according to the Japanese criteria. The causes of death were classified by ICD-10. Mortality risk was evaluated after adjusting for age, sex, smoking, alcohol intake and past medical history such as stroke, heart disease and kidney disease. Results Among the total of 664,926 subjects, we identified 8,051 fatal cases by the end of 2015. The crude death rate was 1.6% for those with MetS, 1.3% for those with preliminary metabolic syndrome, and 1.1% those without MetS. In MetS, the adjusted hazard ratio (95% confidence interval) was 1.08 (1.02-1.15) for all-cause and 1.39 (1.22-1.58) for cardiovascular disease mortality when the reference was for those without MetS. Conclusion The death rate was found to be significantly higher among the participants with MetS.