Hemoglobin concentration and risk of cardiovascular disease in Korean men and women - the Korean heart study.

This study investigated the relationship between hemoglobin concentration and the incidence of cardiovascular diseases (CVD). A total of 407,858 subjects (256,851 men, aged 30-94 yr), who underwent physical examination at 17 Korean nationwide health examination centers, was included in this study. Data regarding CVD incidence were obtained from the Korean National Health Insurance database. In Cox proportional hazard models, men with lower or higher hemoglobin level showed higher hazard ratios (HR) with total CVD (HR, 1.14; 95% Confidence interval [CI], 1.08-1.21 for the 1st quintile; HR, 1.14; 95% CI, 1.09-1.21 for the 5th quintile), ischemic heart disease (HR, 1.16; 95% CI, 1.07-1.26 for the 1st quintile; HR, 1.16; 95% CI, 1.07-1.25 for the 5th quintile), and stroke (HR, 1.13; 95% CI, 1.02-1.25 for the 1st quintile; HR, 1.18; 95% CI, 1.07-1.30 for the 5th quintile) compared to those with mid-level of hemoglobin (3rd quintile). Women with higher hemoglobin level showed higher HR with total CVD (HR, 1.15; 95% CI, 1.01-1.31 for pre-menopausal women; HR, 1.08; 95% CI, 1.01-1.16 for post-menopausal women). We found an independent U-shaped association between hemoglobin level and CVD incidence in Korean population.