Effects of white European, African Caribbean and South Asian ethnicity on homocysteine levels in patients with systolic heart failure.

BACKGROUND: Patients with heart failure of any cause have elevated homocysteine compared to healthy controls. A number of studies in the UK and other western countries have documented higher levels of homocysteine among South Asian than among White European or African Caribbean subjects both in health and in disease, and have suggested that dietary deficiency of folate is the main cause for the difference.
METHODS: Plasma homocysteine, vitamin B(12), and folate levels were measured in a multiethnic UK heart failure clinic population (n=112), and compared to matched control subjects (n=131).
RESULTS: Plasma homocysteine levels were significantly higher in heart failure patients than controls (p<0.001), a result that was consistent across all ethnic groups. There was no difference in homocysteine levels by ethnic group in either patients (p=0.898) or controls (p=0.368). There was no significant difference in levels of folate or B(12) among patients or controls. Using a stepwise linear regression model, homocysteine levels in patients and controls were independently associated with age (p<0.001), vitamin B(12) (p<0.001), folate (p<0.001) and healthy control status (p<0.001), but not with gender, ethnicity, diabetes status, smoking status or BNP levels.
CONCLUSION: This study does not provide evidence of ethnic differences in homocysteine levels between White European, South Asian, and African Caribbean subjects with systolic heart failure. The lack of difference in levels of folate or B(12) among patients or controls, suggests that homocysteine levels - and differences previously seen between South Asians and other ethnic groups - may be driven by dietary factors.