People with high vitamin B12 levels are more likely to die early: JAMA

Netherlands: People with higher blood levels of vitamin B12 are at an increased risk of early death, a recent study in the journal JAMA Network Open has suggested. The death risk in such people was found to be almost twice as compared to those having lower B12 levels.

The researchers were surprised to find that the risk persisted even after adjusting for age, sex, renal function, and other comorbidities, such as a history of cancer. 

Vitamin B12 is a hydrosoluble vitamin that plays a substantial role in 1-carbon metabolism useful for maintaining blood and nerve health. While the deleterious effects of vitamin B12 deficiency, such as anemia, neuropsychiatric symptoms, and other clinical manifestations, are well established, the potential association of high plasma concentrations of vitamin B12 with adverse health outcomes has not been fully explored

Jose L. Flores-Guerrero, University of Groningen, Groningen, the Netherlands, and colleagues, therefore, aimed to assess the association of plasma concentrations of vitamin B12 with all-cause mortality in this population-based cohort study. In addition, they also investigated whether findings were further associated with chronic kidney disease (CKD) or age, considering that approximately 35% of the elderly population has some degree of CKD.

This longitudinal cohort study used post hoc analysis to examine data from participants of the Prevention of Renal and Vascular End-stage Disease (PREVEND) study -- a prospective population-based cohort study in the city of Groningen, the Netherlands. People who completed the second screening visit beginning January 1, 2001, were included and those who were missing values of vitamin B12 plasma concentrations or used vitamin B12 supplementation were excluded. Follow-up time was defined between the beginning of the second screening round to end of follow-up on January 1, 2011. Data analysis was conducted from October 2, 2018, to February 22, 2019.

 A total of 5571 participants (mean [SD] age, 53.5 [12.0] years; 2830 [50.8%] men) were included in analyses. Median (interquartile range) plasma concentration of vitamin B12 was 394.42 (310.38-497.42) pg/mL. 

The study, "Association of Plasma Concentration of Vitamin B12 With All-Cause Mortality in the General Population in the Netherlands," is published in the journal JAMA Network Open. 

DOI: 10.1001/jamanetworkopen.2019.19274