The combined indicator of vitamin B12 status calculated using 3-parameters (3cB12) is negatively associated with mortality among US adults: NHANES 1999 to 2004

Abstract

The association between vitamin B₁₂ status and the risk of mortality is controversial. The combined indicator calculated using 3 traditional parameters (3cB₁₂) can be used to indicate vitamin B₁₂ status. We hypothesize that vitamin B₁₂ deficiency indicated by 3cB₁₂ may be related to high mortality risks. To evaluate the association between 3cB₁₂ and all-cause, cardiovascular disease (CVD) and cancer-related mortality, we used Cox proportional hazard models, cumulative Kaplan–Meier curves, and smooth curve fitting to assess data from NHANES 1999 to 2004. A total of 12,103 adults (20 years and older) were included in the analyses and 3595 participants were determined as deceased. The median follow-up duration was 202 months. In the fully adjusted model, all three mortality rates decreased along with the increase in 3cB₁₂ scores, with hazard ratio (HR) [95% confidence interval (CI)]: 0.81 (0.75, 0.87) for all-cause mortality, HR (95% CI): 0.83 (0.72, 0.95) for CVD mortality, and HR (95% CI): 0.79 (0.66, 0.96) for cancer-related mortality. When 3cB₁₂ was divided into two groups, individuals in the lower 3cB₁₂ group (3cB₁₂ < −0.5) showed increased risks of all-cause mortality [HR (95% CI): 1.73 (1.48, 2.02)] and CVD mortality [HR (95% CI): 1.84 (1.31, 2.59)], as compared to the higher 3cB₁₂ group (3cB₁₂ ≥ −0.5). The smooth fitting curves represented a negative linear relationship between 3cB₁₂ and all three types of mortality (P for nonlinearity >.05). In conclusion, the extrapolation of 3cB₁₂ from conventional metrics affords a novel perspective for evaluating B₁₂ nutritional status and mortality risk.