High prevalence of mild hyperhomocysteinemia and folate, B₁₂ and B₆ deficiencies in an urban population in Karachi, Pakistan

Objective: To find out the prevalence of hyperhomocysteinemia, and deficiencies of folate, vitamin B6 and vitamin B12 in an urban population in Karachi, Pakistan. Methodology: In a pre and post experimental study, eight hundred and seventy-two apparently healthy adults (aged 18-60 years; 355 males and 517 females) were recruited from a low-income urban locality in East of Karachi from February 2006 to March 2007. Fasting venous blood was obtained. Serum was analyzed for folate and vitamin B12. Plasma was analyzed for pyridoxal phosphate (PLP, coenzymic form of B6) and total homocysteine. A group of vitamin-deficient individuals (n=194) was given 3-week supplementation with folic acid (5mg/ day), methycobalamin (0.5mg/day) and pyridoxine hydrochloride (vitamin B6, 50 mg/day). After supplementation, serum/plasma levels of folate, vitamin B12, PLP and homocysteine were again determined. Results: Prevalence of hyperhomocysteinemia (>15μmol/l) was 32%. Similarly percent values of folate deficiency (<3.5ng/ml), vitamin B6 deficiency (PLP<20 nmol/l) and vitamin B12 deficiency (<200pg/ml) in the study population were 27.5%, 33.7% and 9.74%, respectively. Hyperhomocysteinemia was associated with male sex, folate deficiency, vitamin B12 deficiency [OR (95%CI), 8.3(5.7-12.1); 2.5(1.76-3.58); 2.6(1.5-4.5), respectively]. A 3-week supplementation with folic acid, methycobalamin and pyridoxine hydrochloride in vitamindeficient subjects decreased plasma homocysteine levels by 37%. Conclusion: High prevalence estimates of folate, vitamin B12, and vitamin B6 deficiencies appear to be the major determinants of hyperhomocysteinemia in a low income general population in Karachi.