Suppression of Homocysteine Levels by Vitamin B12 and Folates: Age and Gender Dependency in the Jackson Heart Study

Abstract

Objectives To examine factors potentially contributing to premature cardiovascular disease mortality in African Americans (40% versus 20% all other populations), plasma homocysteine, serum vitamin B12 and folate levels were examined for African American participants in the Jackson Heart Study. Methods Of 5,192 African American Jackson Heart Study participants (21–94 years), 5,064 (mean age, 55±13 years; 63% female) had homocysteine levels measured via fasting blood samples, with further assessments of participants’ vitamin B12 (n=1,790) and folate (n=1,788) levels. We used regression analyses to examine age, gender, vitamin B12, and folate with homocysteine levels. Results Homocysteine levels, a purported surrogate risk factor for cardiovascular disease, increased with age, were inversely proportional to folate and vitamin B12 levels (p<0.001), and higher for men of all ages. Conclusions Our results show that, as with other populations, age, gender, vitamin B12, and folate may predict homocysteine levels for African Americans. Diet may be an important predictive factor as well, given the relationships we observed between plasma homocysteine and serum B vitamin levels.

Serum Vitamin B12 Levels in Two Subpopulations of Healthy Workers in Israel: Differences by Land of Birth

“…The present study suggests that land of birth and sex are significant, independent predictors of serum vitamin B 12 levels even after controlling for age and year in which the serum vitamin B 12 was measured. In the present study, serum B 12 levels were elevated in women vs. men, a finding contrary to those of the Jackson Heart Study in which vitamin B 12 levels were elevated in African American men vs. women [9]. The difference in serum vitamin B 12 distribution by sex did not persist, however, when categorized by cut-offs.…”

“…Further, a significant positive correlation was detected between serum B 12 levels and age. This contrasts with reports of no association or inverse associations between B12 levels and age in other populations [9,11,12], or no change. On the other hand, age did not emerge as a significant predictor of serum vitamin B 12 levels after controlling for age and land of birth.…”

Association between plasma homocysteine and hypertension: Results from a cross‐sectional and longitudinal analysis in Beijing’s adult population from 2012 to 2017

“…Differences between these studies might be explained by the participants’ ethnicities. Total plasma Hcy levels have significant gender‐dependent differences although the conclusions of the previous studies were conflicting …”

“…Both conduit and resistance vessel endothelial function may be damaged by elevated Hcy levels, resulting in the development of hypertension . Female hormones, which have been established to have antioxidant effects that may reduce the risk based on Hcy, may be responsible for the observed differences …”

A common TCN1 loss-of-function variant is associated with lower vitamin B12 concentration in African Americans

“…At the baseline examination, VB 12 was measured in plasma in a subset of 1851 JHS participants using a homogenous enzyme immunoassay system and Hitachi 911 equipment (Roche Diagnostics, Indianapolis, IN). 19 A total of 3406 JHS participants underwent 303 coverage WGS through the TOPMed project at the Northwest Genome Center at the University of Washington, and genotype calling was performed by the Informatics Resource Center at the University of Michigan, as previously described. 20 After quality control (supplemental Methods), a total of 29 665 030 variants (minor allele frequency .…”