ABSTRACT
Vitamin B12 (B12) is a molecule involved in several biological. Abnormally high levels are frequently found, but their causes can be multiple, and consequences have not been clearly elucidated. The objective of this review was to summarize the current evidence on the associations of elevated B12 and the development of cancer, and all-cause mortality in adults. Six references looking at mortality and seven looking at cancer risk were included. The evidence suggests an association between elevated B12 with a higher risk of cancer, with risk ratios ranging 1,88 to 5,9. There was less consistent evidence linking vitamin B12 and mortality.
Elevated B12 levels exceeding 1000 pg/L, if sustained and unexplainable, warrant a comprehensive individual assessment of each patient. This evaluation should encompass various potential factors contributing to the elevation, aiming to effectively guide the diagnostic process of neoplastic diseases.Clinical longitudinal observational studies have suggested a potential link between heightened B12 levels and the risks of cancer and mortality. Nonetheless, these studies have been retrospective cohort studies, and lack a defined threshold point of B12 levels.Studies have documented a positive correlation between elevated levels of B12 and the incidence of lung, pancreatic, and liver cancers, as well as certain hematological neoplasms, particularly those related to the myeloid lineage. Conversely, a consistent negative association has been observed in the context of breast cancer. Findings concerning neoplasms of the lower gastrointestinal tract and prostate display contradictory outcomes.The diagnostic significance of elevated B12 levels among patients already diagnosed with cancer remains uncertain and could potentially be linked to reverse causality.
ABSTRACT
OBJECTIVES: To assess whether the nutrition risk index (NRI) is associated with the risk of bacteremia within the first days after autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM). MATERIALS AND METHODS: Retrospective cohort study of adult patients with MM taken to ASCT at the Hospital Universitario San Ignacio (Bogotá, Colombia) between 2005 and 2019. The outcome of interest was the incidence of bacteremia at 30 days. Multivariate analysis was used to identify whether the NRI was associated with bacteremia, controlling by different confounding variables. RESULTS: One hundred and twenty-four patients with a median age of 58.5 years (IQR: 54-64) were included. 47.1% were in stage ISS III. 36.0% had moderate or severe malnourishment (NRI < 97.5). 11.2% presented bacteremia in the first 30 days after transplantation. In the univariate analysis, the NRI < 97.5 was associated with bacteremia (OR: 1.88; 95% CI: 1.30-2.72, P = .001); however, this association was not significant in the multivariate analysis, unlike the presence of mucositis (OR: 11.59; 95% CI: 1.9-68.3, <0.01), one or more previous lines of therapy (OR: 12.0; 95% CI: 2.1-67.4; P < .01), and duration of aplasia (OR: 1.70; 95% CI: 1.2-2.4, P < .01). CONCLUSIONS: Patients with moderate or severe malnourishment have a higher incidence of bacteremia in the 30 days post-ASCT in patients with MM. Additional risk factors associated with bacteremia include the presence of mucositis, one or more previous lines of therapy, and the duration of aplasia.
