Background: A high cobalamin level has been related to non-malignant diseases (mainly liver diseases, alcoholism, and renal diseases) and cancer (hematological malignancies and solid cancers such as liver and stomach cancer). However, a previous high level of cobalamin and the implications in the possible development of cancer is still unclear. The main aim of this study was to describe if a previous high cobalamin level is a determinant in the future development of cancer in five years of follow-up. The secondary objective was to determine any differences between cancer groups.
Methods: A retrospective study was performed. Two databases were employed. The first one included all patients who had a determination of cobalamin in a routine blood test during the year 2010 (a total of 44,166 patients). The second one showed every patient who was admitted to the reference hospital, Hospital Clinico Universitario de Valladolid, during the following five years. Finally, a number of 6710 patients was included. Both databases belong to the medical records of the Hospital Data Surveillance System and are completely validated. Multivariate logistic regression analyses were employed to evaluate the association between cobalamin levels and the appearance of cancer (total and in each subgroup). All analyses were performed using IBM SPSS 24 software (IBM Corp., Armonk, NY, USA).
Results: The sample studied showed a clear association between the risk of hematological cancer and a previous high Cbl level. This relationship was higher among patients with the highest levels (over 779 pmol/L), showing almost two times more risk for development of hematological malignance within 5 years in the multivariate analysis (OR: 1.975, 95% CI: 1.056-3.697, P=0.033). Hematological malignancies were mostly diagnosed within the first three years (86.6%), showing a similar percentage in those three years. There was no association between this previous level and the development of any other type of cancer.
Conclusions: Our study shows that a high cobalamin plasma level (hypervitaminosis) is associated with the development of hematologic cancer within five years after the measurement. The clinical implication of these findings, together with the clinical suspicion, reinforces the necessity of carrying out specific screening hematological tests in patients with not justified elevated plasma cobalamin levels. New prospective and multicenter studies are necessary to validate these results.