Biological variation of cardiac biomarkers in athletes during an entire sport season

Abstract

Objectives: Cardiac biomarkers are useful for the diagnostic and prognostic assessment of myocardial injury (MI) and heart failure. By measuring specific proteins released into the bloodstream during heart stress or damage, these biomarkers help clinicians detect the presence and extent of heart injury and tailor appropriate treatment plans. This study aims to provide robust biological variation (BV) data for cardiac biomarkers in athletes, specifically focusing on those applied to detect or exclude MI, such as myoglobin, creatine kinase-myocardial band (CK-MB) and cardiac troponins (cTn), and those related to heart failure and cardiac dysfunction, brain natriuretic peptide (BNP) and N-terminal brain natriuretic pro-peptide (NT-proBNP).

Methods: Thirty athletes participated, providing monthly fasting blood samples over 11 months. Samples were analyzed using chemiluminescent immunoassays and statistical analyses were conducted using the classical ANOVA method, a linear mixed model and a Bayesian approach.

Results: The study observed significant gender differences in biomarker concentrations, with higher BNP and NT-proBNP in females and higher myoglobin and CK-MB in males. Physical activity within 24 h before sampling notably affected CK-MB, myoglobin, and hs-cTnI variability. The BV estimates demonstrated high individuality for most biomarkers, suggesting their potential for personalized monitoring. The study also revealed substantial heterogeneity for NT-proBNP and BNP within the population.

Conclusions: These findings underscore the importance of considering gender-specific reference intervals and the impact of recent physical activity when interpreting cardiac biomarkers in athletes. The study delivers new BV estimates for CK-MB and myoglobin while emphasizing the need for tailored clinical assessments in athlete populations.

Keywords: athletes; biological variation; cardiac biomarkers; myocardial injury.