Haemoglobin levels as a predictor for the occurrence of future cardiovascular events in adults-Sex-dependent results from the EPIC trial

Background: The impact of hemoglobin levels on the occurrence of future health events remains equivocal. Due to its integral role in human hemostasis, both, high and low hemoglobin levels may play a significant role in the development of future cardiovascular (CV) events in otherwise healthy adults. Methods: Data from the European Prospective Investigation into Cancer (EPIC)-InterAct cohort was analyzed. In 13.648 individuals, physical activity, body mass index, family history of cardiovascular events, kidney function, smoking status, blood pressure and LDL levels were modelled to concomitant hemoglobin levels and correlated to the occurrence of clinically-overt cardiovascular events and death over a 21-year period. (Sex specific) cox regression analysis were used to develop hazard ratios (HRs) for CV events and all-cause mortality.Results: Anemia (hemoglobin (HGB) levels < 13.0 g/dl in men and < 12.0 g/dl in non-pregnant women) were associated with an increased all-cause mortality in men but not in women (HR anemia in men 1.4 (1.2; 1.6)) p=<0.0001).This was particularly visible with increasing age. Various sex specific Cox regression models, accounting for several CV risk factors confirmed these results. The incidence of future CV events and myocardial infarction was significantly influenced by underlying HGB levels in men with increasing age but not in women.Conclusion: The influence of HGB levels on future cardiovascular events is sex-dependent. In men, presenting with anemia at baseline, the overall survival probability was impaired with increasing age. After adjusting for several CV risk factors, abnormal hemoglobin levels could be identified as a risk factor for the development of clinically-apparent future CV events in men. None of these effects were observed in women.