"Metabolically Healthy" Obesity and Hyperuricemia Increase Risk for Hypertension and Diabetes: 5-year Japanese Cohort Study.

OBJECTIVE: Whether obesity without metabolic syndrome (i.e., "metabolically healthy" obesity) confers similar or less metabolic risk remains controversial.

METHODS: A retrospective 5-year cohort study of 9,721 Japanese subjects (48.5 ± 10.5 years, 4,160 men) was conducted in 2004 and reevaluated 5 years later. Subjects were excluded if they were hypertensive or diabetic or were receiving medications for dyslipidemia and/or gout or hyperuricemia in 2004. Study subjects were categorized according to baseline BMI  ≥ 25 kg/m2 (overweight/obesity) and < 25 kg/m2 (lean/normal weight) and also whether they had metabolic syndrome. The cumulative incidence of hypertension and diabetes over 5 years between groups was assessed. A second analysis evaluated whether baseline hyperuricemia provided additional risk.

RESULTS: Subjects with overweight/obesity but without metabolic syndrome carried increased cumulative incidence of hypertension (14.6% vs. 7.2%, P < 0.001) and diabetes (2.6% vs. 1.1%, P = 0.004) over 5 years compared to lean/normal subjects without metabolic syndrome. Overweight/obesity conferred an increased risk for diabetes even in individuals with normal fasting blood glucose. Hyperuricemia became an independent risk factor for developing hypertension over 5 years in lean/normal subjects without metabolic syndrome. A 1 mg/dL increase in serum uric acid carried increased risk for hypertension (19%) and diabetes (27%).

CONCLUSIONS: Metabolically healthy obesity and hyperuricemia confer increased risk for hypertension and diabetes.