vitamin b12 deficiency common among patients with vascular disease, and a major determinant ...

Vitamin B12 deficiency common among patients with vascular disease, and a major determinant of elevated homocysteine levels and increased carotid plaque

Since carotid plaque area is a strong predictor of cardiovascular events, and as high homocysteine levels, which are associated with plaque formation, can result from inadequate intake of folate and vitamin B12, now that folic acid fortification is widespread in North America, vitamin B12 has become an important determinant of homocysteine levels. Canadian, Italian and US researchers sought to determine the prevalence of low serum levels of vitamin B12, and their relation to homocysteine levels and carotid plaque area among patients referred for treatment of vascular disease since folic acid fortification of enriched grain products. They evaluated 421 consecutive new patients with complete data whom they saw in a vascular disease prevention clinics between 1998 and 2002, and measured total carotid plaque area by ultrasound and determined homocysteine and serum vitamin B12 levels in all patients.

They found that the patients, 215 men and 206 women, ranged in age from 37 to 90 years (mean 66 years). Most were taking medications for hypertension (67%) and dyslipidemia (62%). 73 patients (17%) had vitamin B12 deficiency (vitamin B12 level < 258 pmol/L with homocysteine level > 14 µmol/L or methylmalonic acid level > 271 nmol/L). The mean area of carotid plaque was significantly larger among the group of patients whose vitamin B12 level was below the median of 253 pmol/L than among those whose vitamin B12 level was above the median: 1.36 cm2 v. 1.09 cm2; p = 0.016.

The researchers concluded: “Vitamin B12 deficiency is surprisingly common among patients with vascular disease, and, in the setting of folic acid fortification, low serum vitamin B12 levels are a major determinant of elevated homocysteine levels and increased carotid plaque area.”

See however the comments in a letter to the editor: Haphazard definition of B12 deficiency by Joel G. Ray and David E.C. Cole of the University of Toronto. To view it, click here.

CMAJ June 7, 2005; 172 (12). doi:10.1503/cmaj.045055. © 2005 CMA Media Inc. or its licensors
Vitamin B12, homocysteine and carotid plaque in the era of folic acid fortification of enriched cereal grain products, Julie Robertson, Francesco Iemolo, Sally P. Stabler, Robert H. Allen and J. David Spence. Correspondence to Dr J David Spence dspence@robarts.ca

Category T. Endocrine/Metabolic/Nutritional, K. Circulatory. Keywords: vitamin B12, vitamin B12 deficiency, folic acid, folic acid fortification, homocysteine, carotid plaque, vascular disease, CVD, cohort study
Synopsis edited by Professor Wes Fabb, Melbourne. Posted on Global Family Doctor 12 July 2005