Multi-index evaluation system and relevant critical values for monitoring iron status in Chinese athletes

BACKGROUND: The aim of this study was to investigate the iron status of Chinese professional athletes by observing comprehensive biomarkers related to iron metabolism and to establish threshold values of these markers for this population group.METHODS: Hematological and biochemical markers of 227 healthy athletes (84 men and 143 women) from Shanghai professional sports teams were analyzed to establish reference values for serum ferritin, soluble transferrin receptor, the transferrin receptor-ferritin index and hepcidin that are specific for Chinese athletes. Correlation analysis was also performed to investigate the relationships of iron status with sex hormone (testosterone) levels and oxidative stress.RESULTS: Among the parameters related to iron metabolism, serum ferritin, the transferrin receptor-ferritin index and hepcidin were significantly different between male and female athletes, while soluble transferrin receptor showed no significant difference. The critical values of serum ferritin were proposed to be 30 ng/mL for male athletes and 12 ng/mL for female athletes. The threshold of the soluble transferrin receptor was determined to be 25 nmol/L. Serum ferritin showed a positive correlation with oxidative stress parameters, and testosterone was negatively correlated with hepcidin.CONCLUSIONS: The proposition of specific reference values and the joint evaluation of multi-index values could provide more comprehensive information about athletes’ iron status and will help sports physicians make more justified intervention decisions.