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This study was designed to investigate the plasma level of amino-terminal pro-brain natriuretic peptide (NT-proBNP) and its influencing factors in a community-based superficially healthy population in Beijing area of China.
We measured plasma NT-proBNP level by fluoroimmunoassay between March 2012 and July 2012 from 1034 superficially healthy subjects，including 486 men and 548 women. The inclusion criteria of superficially healthy subjects include no previous history of cardiovascular disease, lung disease, kidney disease and diabetes mellitus; never taking any cardiovascular drugs; normal systolic and diastolic function by echocardiography; normal ECG and sinus rhythm; serum creatinine <133 mol/L and estimated glomerular filtration rate (eGFR) >45 ml·min-1·1.73m-2 (≥55 years old) or >60 ml·min-1·1.73m-2(<55years old). Empiric method was used to determine the reference value and influencing factors were analyzed.
Age and gender are important factors affecting the level of NT-proBNP in superficially healthy subjects. NT-proBNP plasma level is significantly higher in women than in men within each age strata below 75 years old, i.e. <45, 45-54, 55-64 and 65-74 years old (P = 0.005, 0.001, 0.001, 0.011 respectively), but not different when older than 75 years old (P=0.504). NT-proBNP level also increases with age irrespective of gender. Body mass index (BMI) is another independent influencing factor of NT-proBNP (P< 0.001), while estimated glomerular filtration rate is not influencing factor in subjects with relatively preserved renal function. The reference range of NT-proBNP is <133ng/L for men and <289ng/L for women aged <55 years old, <185ng/L for men and <333ng/L for women aged between 55 and 64 years old，and <465ng/L for men and <378ng/L for women aged ≥75 years old.
The major influencing factors of NT-proBNP level in the healthy population are age, gender and BMI. Therefore, It is essential to establish normal reference range of NT-proBNP according to these factors for Chinese population.
Key words: Natriuretic peptide,brain; Reference value