A revised definition of the metabolic syndrome predicts coronary artery disease and ischemic stroke after adjusting for low density lipoprotein cholesterol in a 13-year cohort study of Japanese: the Suita study

Abstract

Objective: Recently, several major organizations have proposed a unified definition for the metabolic syndrome (MetS), which should be evaluated in multiethnic groups. The effect of Mets on the incidence of cardiovascular disease needs to be assessed after adjusting for serum low density lipoprotein cholesterol (LDLC), a major risk factor for atherosclerotic diseases. This is especially needed to be evaluated in Asian populations with low incidence of coronary artery disease (CAD).

Methods: We conducted a 13-year prospective study of 4939 Japanese living in an urban area. The MetS was defined using a unified classification that included cut-off points for waist circumference in Asians. The multivariable adjusted hazard ratios (HRs) of MetS for CAD and stroke were calculated using a Cox proportional model adjusted for other potential confounding factors with LDLC.

Results and conclusion: During the follow-up period, there were 155 cases of CAD and 204 of stroke including 118 cerebral infarctions. In participants under 65 years old, the multivariable HRs of MetS for CAD were 1.21 (95% C.I., 0.64-2.28) in men and 4.44 (95% C.I., 1.73-11.4) in women; the HRs for ischemic stroke were 3.24 (95% C.I., 1.55-6.77) in men and 3.99 (95% C.I., 1.34-11.8) in women. In participants aged 65 years old and over, MetS only showed a significant association with CAD in men (HR 1.89, 95% C.I., 1.11-3.21). Serum LDLC was associated with increased risk of CAD in men irrespective of age group; however, it was not associated with CAD in women. There was no association between serum LDLC and ischemic stroke in any group stratified by sex and the age of 65. These results indicate that the new uniform MetS definition is useful for detecting high risk individuals, especially for middle-aged population. However, continuous screening for hypercholesterolemia is necessary to prevent CAD, especially in men, even in Asian countries such as Japan.