Vitamin B12 deficiency is associated with coronary artery disease in an Indian population

Abstract

The incidence of coronary artery disease (CAD) is increasing at an alarming rate, especially in developing countries, such as India. It is often advocated that a vegetarian lifestyle could reduce the burden of CAD. However, in spite of a majority of Indians being vegetarians, the incidence of CAD is highest in this population. This may be due to deficiency of vitamin B12, a micronutrient, sourced only from animal products. Herein, we assessed the effect of vitamin B12 with respect to CAD in 816 individuals (368 CAD patients and 448 controls) recruited from a tertiary care center in New Delhi, India. We found that vitamin B12 levels were significantly lower in CAD patients than in controls (p<0.0001). Also, vegetarians were found to have significantly lower vitamin B12 concentrations (p=0.0001) and higher incidence of CAD (p=0.01). Interestingly, elevated homocysteine levels, a hallmark of vitamin B12 deficiency, was not associated with CAD. In contrast, cysteine levels were significantly higher in CAD patients than in controls (p=0.004). We believe that, when vitamin B12 is deficient, homocysteine is rapidly metabolized via the transsulfuration pathway leading to increased cysteine levels.