Associations between polycythemia and cardiometabolic risk factors in middle-aged men

Polycythemia increases blood viscosity and causes thrombogenesis in cardiovascular disease. However, relationships between polycythemia and cardiometabolic risk factors in a general population remain to be determined.

Subjects were middle-aged Japanese men (n = 11261) receiving annual health checkup examinations. Relationships of polycythemia, defined as hemoglobin concentrations of 16.5 g/dl or higher, with cardiometabolic risk factors, including obesity, hypertension, dyslipidemia and diabetes, were investigated.

Both in univariable analysis and multivariable analysis with adjustment for age, histories of smoking, alcohol drinking and regular exercise, and medication therapy for hypertension, dyslipidemia or diabetes, waist-to-height ratio, systolic and diastolic blood pressure, triglycerides, LDL cholesterol, cardiometabolic index (CMI) and hemoglobin A_1c were significantly higher and HDL cholesterol was significantly lower in the polycythemic group than in the non-polycythemic group. The above associations between polycythemia and cardiovascular risk factors were also found in the sub-analysis for nonsmokers (n = 4937). The odds ratios (ORs) of the polycythemic vs. non-polycythemic groups for high CMI and metabolic syndrome (MS) were significantly high when compared with the reference level in the multivariable analysis (OR with 95% confidence interval: high CMI, 2.18 [1.91 ∼ 2.50]; MS, 2.39 [2.02 ∼ 2.85]).

Polycythemia showed smoking-independent associations with cardiometabolic risk factors including visceral obesity, hypertension, dyslipidemia, diabetes and metabolic syndrome. Thus, polycythemia is a potential discriminator of cardiovascular risk in the general population.