Increased serum urate concentration is a frequent finding in patients with hypertension. Since hyperuricemia is associated with obesity, renal disease, hyperlipidemia, and atherosclerosis, whether or not serum urate is a cardiovascular risk factor per se has remained elusive.
The subjects were 210 Turkish male and 210 female adults over 20 years of age. None had diabetes mellitus, endocrine diseases, or renal or hepatic disease, and those receiving antihypertensive drugs, systemic corticosteroids, or lipid-lowering drugs were excluded. Height, weight, blood pressure, serum glucose, lipid profiles, serum insulin, DHEA-SO₄, and leptin were measured in the morning after an overnight fast.
Women had significantly higher mean leptin (20.3 ± 0.88 ng/mL vs 5.78 ± 0.39 ng/mL, P < 0.001) and lower mean uric acid (248.03 ± 4.76 µmol/L vs 311.6 ± 5.35 µmol/L, P < 0.001), triglyceride (1.42 ± 0.06 mmol/L vs 1.61 ± 0.06 mmol/L, P < 0.001), and DHEA-SO₄ (3.02 ± 0.17 µmol/L vs 4.43 ± 0.19 µmol/L, P < 0.001) concentrations than men, even when adjusted for BMI. On univariate correlation analysis, leptin showed the strongest association with BMI in both sexes and also correlated significantly with BMI, insulin, uric acid, glucose, total cholesterol, and triglycerides in males and BMI, insulin, uric acid, total cholesterol, apo B, and creatinine in females after adjustment for age and BMI. A statistical model containing creatinine, leptin, insulin, and triglycerides accounted for 34% of the variance in serum uric acid levels in men, whereas another consisting of creatinine, triglycerides, leptin, SBP, and insulin explained 42% of the variance in serum uric acid in women.
The present study suggests that leptin could be one of the possible candidates for the missing link between obesity and hyperuricemia. Our study may also suggest that hyperuricemia is not only a metabolic end product but also a marker of a major pressor or pathogenic mechanism underlying the hypertension in obesity.