Hyperhomocysteinemia as a cardiovascular risk factor in Indian women: determinants and directionality

To assess Homocysteine (Hcy), vitamin B12 and folic acid (FA) concentrations in resident Indian women and to study their correlation with traditional risk factors for coronary artery disease.

The study included 137 consecutive women who attended a health care program (HCP) for women at and above 40 years of age (MAITREYI's HCP). Fasting blood samples for Hcy, B12 and folate were collected on ice, centrifuged within 1/2 hour and stored at -70 degrees C till assayed using a chemiluminescence method. All women underwent a screening for their general health profile including cardiovascular health.

Of the 137 women screened 21 were excluded because of presence of factors known to affect Hcy levels (history of existing CAD had hypothyroidism or were on multivitamin supplements). The median Hcy, folic acid and vitamin B12 levels were 9 pmol/L (range 4.2-38.6), 8.8 ng/ml (2.3-31.6 range) and 214 pg/ml (100-2400 range) respectively. The prevalence of hyperhomocysteinemia (>15 pmol/L) was 24.2%. Correlation for continuous variables using spearman's test and for categorical variables with chi-square test showed a highly significant negative correlation with vitamin B12 (p < 0.001) and FA (p<0.002). Both systolic (p < 0.05) and diastolic (p < 0.02) and diastolic blood pressure also showed a significant correlation. However, no correlation was found between plasma Hcy and blood sugars, lipids, age, body mass index and menopausal status. The CAD risk was assessed using Framingham risk scores and this too did not show a correlation with plasma Hcy.

A large number of women from the present study had hyperhomocysteinemia and were deficient in vitamin B12. A significant negative correlation between vitamin B12 and plasma Hcy levels was foundin these older women. Most Indian studies including the present one do not show a positive correlation between elevated Hcy levels and CAD in spite of a large percentage of persons showing elevated homocysteine levels. Since high Hcy levels are recognized as an independent risk factor for CAD, these findings of absence of correlation between Hcy and CAD as reported in various Indian studies need to be explored and explained.