The criteria for metabolic syndrome and the national health screening and education system in Japan

Abstract

Two major definitions of metabolic syndrome have been proposed. One focuses on the accumulation of risk factors, a measure used by the American Heart Association (AHA) and the National Heart, Lung, and Blood Institute (NHLBI); the other focuses on abdominal obesity, a measure used by the International Diabetes Federation (IDF) and the Japanese government. The latter definition takes waist circumference (WC) into consideration as an obligatory component, whereas the former does not. In 2009, the IDF, NHLBI, AHA, and other organizations attempted to unify these criteria; as a result, WC is no longer an obligatory component of those systems, while it remains obligatory in the Japanese criteria. In 2008, a new Japanese cardiovascular screening and education system focused on metabolic syndrome was launched. People undergoing screening are classified into three groups according to the presence of abdominal obesity and the number of metabolic risk factors, and receive health educational support from insurers. This system has yielded several beneficial outcomes: the visibility of metabolic syndrome at the population level has drastically improved; preventive measures have been directed toward metabolic syndrome, which is expected to become more prevalent in future generations; and a post-screening education system has been established. However, several problems with the current system have been identified and are under debate. In this review, we discuss topics related to metabolic syndrome, including (1) the Japanese criteria for metabolic syndrome; (2) metabolic syndrome and the universal health screening and education system; and (3) recent debates about Japanese criteria for metabolic syndrome.

Keywords: Abdominal obesity; Health education; Metabolic syndrome X; Risk factors; Universal health screening.

Figure 1.

Selected criteria of metabolic syndrome. IDF, International Diabetes Federation; WC, waist circumference; TG, triglyceride; HDL, high-density lipoprotein cholesterol; BP, blood pressure; FPG, fasting plasma glucose; AHA, American Heart Association; NHLBI, National Heart Lung and Blood Institute; WHF, World Heart Federation; IAS, International Atherosclerosis Society; IASO, International Association for the Study of Obesity; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure.

Figure 2.

Current system of post-screening measures for metabolic syndrome. ¹Additional risk factors: hyperglycemia (FBS ≥100 mg/dL or HbA1c ≥5.6%); dyslipidemia (TG ≥150 mg/dL or HDL ≤40 mg/dL); hypertension (SBP ≥130 mmHg or DBP ≥ 85 mmHg); Smoking. FBS, fasting blood sugar; HbAlc, glycated hemoglobin; TG, triglyceride; HDL, high-density lipoprotein cholesterol; SBP, systolic blood pressure; DBP, diastolic blood pressure.