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OBJECTIVES: Although the existence of metabolically healthy obese (MHO) individuals has been recognized, little is known regarding metabolic health status in these subjects over time. Thus, we evaluated longitudinal changes in metabolic parameters among MHO subjects compared with metabolically healthy, normal-weight (MHNW) subjects. METHODS: A cohort study was performed on 2599 Korean men, 30 --59 years of age, with no evidence of fatty liver disease on ultrasound and no traits of metabolic syndrome at baseline. BMI was categorized based on criteria for Asian population. Study participants were followed annually or biennially between 2002 and 2009. At each visit, the fatty liver on ultrasound was assessed and metabolic abnormalities were measured. Parametric Cox models and a pooled logistic regression models were used to evaluate the relationships of BMI with incident metabolic abnormalities. RESULTS: During 9647.1 person-years of follow-up, 1673 participants developed metabolic abnormalities. After adjusting for age, smoking, alcohol intake and exercise, higher baseline BMI categories predicted increased incidences of metabolic abnormalities in a dose-response manner. The hazard ratios (95% confidence intervals) for hypertriglyceridemia, prediabetes, pre-hypertension, low high-density lipoprotein-cholesterol, fatty liver, elevated high sensitivity-C reactive protein, elevated homeostasis model assessment of insulin resistance, any metabolic abnormality and metabolic syndrome among the MHO subjects compared with the MHNW subjects were 1.51 (1. Keywords: body mass index; risk factors; insulin resistance; metabolic syndrome X; follow-up studies INTRODUCTIONObesity is a risk factor for cardiometabolic disorders such as type 2 diabetes mellitus and cardiovascular disease. 1,2 However, the incidence of obesity-related metabolic disturbances varies widely among obese individuals. 3,4 A unique subset of obese individuals that appears to be protected from obesity-related metabolic abnormalities has been identified. 3,5 These individuals, referred to as metabolically healthy but obese (MHO), are relatively insulin sensitive and have a favorable cardiovascular risk profile despite excessive body fat. 6 Previous studies indicate that MHO individuals, regardless of body mass index, are not at increased risk for cardiovascular diseases compared with normal-weight subjects without insulin resistance. 7,8 Therefore, weight loss may not be deemed necessary among these individuals.Recent longitudinal studies have observed that obese men without metabolic syndrome were at an increased risk for cardiovascular events or death compared with normal-weight individuals without metabolic syndrome. 9,10 Other studies observed that the MHO subset had an intermediate cardiovascular risk between healthy non-obese subjects and insulin resistant subjects. 11,12 Furthermore, recent intervention studies showed that lifestyle-induced weight loss among MHO individuals was associated with improved insulin sensitivity. 13,14

Summary Objectives:  We investigated the association between metabolic syndrome (MS) and health‐related quality of life (HRQOL) assessed using generalised and obesity‐specific QOL instruments. Methods:  We recruited 456 outpatients [age: 19–81 years, body mass index (BMI): 16.3–36.7 kg/m2] in the primary care division from 12 general hospitals in Korea. HRQOL was measured using EuroQol comprising the health states descriptive system (EQ‐5D) and visual analogue scale (EQ‐VAS) as a general instrument. The Korean Obesity‐related QOL scale (KOQOL) composed of six domains was used as a disease‐specific QOL instrument. MS was defined on the basis of International Diabetes Federation (IDF) criteria with Korean‐specific waist circumference cutoffs (men: 90 cm, women: 85 cm). Results:  Subjects with MS displayed significantly higher impairment of EQ‐5D and KOQOL. Binary logistic regression analysis of MS patients with controls for age, gender, smoking, alcohol, exercise, education, income, marital status and medication history disclosed odds ratio (OR) values of 2.13 (1.33–3.41) for impaired total KOQOL, 2.07 (1.31–3.27) for impaired physical health, 1.63 (1.03–2.60) for impaired work‐related health, 2.42 (1.45–4.04) for impaired routine life, 2.08 (1.27–3.40) for impaired sexual life and 2.56 (1.59–4.11) for diet distress. Among the EQ‐5D dimensions, only pain/discomfort displayed a significantly increased OR of 1.60 (1.01–2.56) in MS group. Conclusions:  Subjects with MS displayed a significantly impaired HRQOL compared with those without MS. MS and HRQOL were more strongly associated in obesity‐specific QOL than in generalised QOL.