N-Terminal Pro-B-type Natriuretic Peptide Levels in the Korean General Population

Background and Objectives: B-type natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP) levels may serve as a useful marker of cardiovascular risk for screening of the general population. We evaluated reference levels and distribution of NT-proBNP in the Korean general population based on a large cohort study. Subjects and Methods: We included 1,518 adult subjects (ages 40-69) of a community-based cohort from the Korea Rural Genomic Cohort (KRGC) Study. Thorough biochemical and clinical data were recorded for all subjects. Levels of NT-proBNP from all participants were determined. In order to determine normal reference levels, subjects with factors known to influence NT-proBNP levels were excluded. Results: The characteristics of the cohort are described below; subjects were 41.2% male, and the mean age was 54.8${\pm}$8.4 years. The distribution of risk factors for cardiovascular disease in the cohort included hypertension (25%), left ventricular hypertrophy by electrocardiography (ECG-LVH) (15%), hypercholestolemia (4.5%), smoking (32%), diabetes (10.9%), history of coronary heart disease (4.9%), history of heart failure (0.9%), symptoms of heart failure (6.1%), elevated serum creatinine (${\geq}$1.5, 3.7%), and severe obesity (body mass index >30 kg/m$^2$, 4.6%). The levels of NT-proBNP of all subjects are shown below; the mean was 60.1${\pm}$42.1, and the median was 36.5 pg/mL. In addition, the levels of NT-proBNP of normal subjects (which did not have any risk factors, n=224) are shown below; the mean was 40.8, and the median was 32.1 pg/mL. In normal subjects, the NTproBNP level was slightly higher in females (25.7${\pm}$24.8 vs. 46.9${\pm}$35.4, p<0.001). NT-proBNP level increased with age in both the normal population and the total population. There were no significant differences in NT-proBNP levels in subjects who smoked, or had diabetes mellitus, hypertension or ECG-LVH. However, in subjects with a history of congestive heart failure (CHF) (58.5${\pm}$103.29 vs. 213.8${\pm}$258.8, p<0.005), elevated serum creatinine levels (${\geq}$1.5 mg/dL, 146.2${\pm}$98.2 vs. 54.3${\pm}$38.1, p<0.001), or who were older (${\geq}$60, 48.4 vs. 84.2${\pm}$139.5 pg/mL, p<0.05), the BNP level was higher. In addition, patients with more than 3 risk factors for CHF had higher BNP levels (risk 0: 40.8${\pm}$34.0, 1-2: 57.4${\pm}$93.2, ${\geq}$3: 85.0${\pm}$152.9 pg/mL). NT-proBNP levels were also related with age, sex, urine albumin, serum Cr, and high sensitivity C-reactive protein (p<0.05). Conclusion: We determined the reference value and distribution of NT-proBNP in the Korean adult general population. We also found that adjustments for the independent effects of age, sex and renal function appear necessary when determining cardiac risk based on proBNP levels.