Iqbal M P, Ishaq M, Kazmi K A, Yousuf F A, Mehboobali N, Ali S A, Khan A H, Waqar M A
Department of Biological & Biomedical Sciences, The Aga Khan University, Stadium Road, PO Box 3500, Karachi 74800, Pakistan.
Nutr Metab Cardiovasc Dis. 2005 Apr;15(2):100-8. doi: 10.1016/j.numecd.2004.05.003. Epub 2005 Apr 14.
Pakistani people belong to an ethnic group which has the highest rate of coronary artery disease (CAD). We investigated the possible correlation between deficiency of vitamins B6, B12 or folic acid and hyperhomocysteinemia in Pakistani patients with acute myocardial infarction (AMI). A case-control study was carried out involving 224 AMI patients (age 30-70 years; 55 females and 169 males) and 126 normal healthy subjects (age 31-70 years; 35 females and 91 males).
Fasting venous blood was obtained from cases and controls. Serum was analyzed for folic acid and B12 using radioassays. Plasma was analyzed for pyridoxal phosphate (PLP; coenzymic form of B6) using a radioenzymatic assay and for total homocysteine using a fluorescence polarization immunoassay. Mean serum B12 concentration in AMI patients was found to be significantly lower than the mean for controls (241+/-185 pg/ml vs 608+/-341 pg/ml; p < 0.001). Mean serum folate level in patients was also found to be lower than controls (3.35+/-3.78 ng/ml vs 4.93+/-2.93 ng/ml), however, the differences were not statistically significant. Similarly, mean PLP concentration in plasma of cases (19.4+/-24.4 nmol/l) was lower than the concentration in controls (23.2+/-17.6 nmol/l), but the difference was not statistically significant. Mean plasma homocysteine level in AMI cases (18+/-8.36 micromol/l) was higher than the mean level in controls (16.4+/-4.9 micromol/l), but not to a significant extent. However, this mean homocysteine concentration in normal healthy subjects was among the highest reported in the literature and was significantly more than mean values reported in most Eastern and Western studies. Compared to controls, there was significantly greater deficiency of folate (32.5% vs 67.1%), B12 (3.2% vs 63.4%) and PLP (49.2% vs 74.1%) in AMI patients. Deficiencies of folate, B12 and PLP were defined as serum folate levels less than 3.5 ng/ml, serum levels of B12 less than 200 pg/ml and plasma PLP levels less than 20 nmol/l. Mean plasma homocysteine levels in smokers were found to be significantly higher in both cases and controls. Similarly, mean serum folate levels in smokers (compared to nonsmokers) were significantly lower in both cases and controls.
Substantial nutritional deficiencies of these three vitamins along with mild hyperhomocysteinemia, perhaps through an interplay with the classical cardiovascular risk factors (highly prevalent in this population), could be further aggravating the risk of CAD in the Pakistani population.
巴基斯坦人所属的族群患冠状动脉疾病（CAD）的几率最高。我们调查了巴基斯坦急性心肌梗死（AMI）患者中维生素B6、B12或叶酸缺乏与高同型半胱氨酸血症之间可能存在的相关性。开展了一项病例对照研究，纳入224例AMI患者（年龄30 - 70岁；女性55例，男性169例）和126名正常健康受试者（年龄31 - 70岁；女性35例，男性91例）。
采集病例组和对照组的空腹静脉血。采用放射分析法检测血清中的叶酸和B12。采用放射酶法检测血浆中的磷酸吡哆醛（PLP；B6的辅酶形式），采用荧光偏振免疫分析法检测总同型半胱氨酸。发现AMI患者的血清B12平均浓度显著低于对照组（241±185 pg/ml对608±341 pg/ml；p < 0.001）。还发现患者的血清叶酸水平低于对照组（3.35±3.78 ng/ml对4.93±2.93 ng/ml），然而，差异无统计学意义。同样，病例组血浆中PLP的平均浓度（19.4±24.4 nmol/l）低于对照组（23.2±17.6 nmol/l），但差异无统计学意义。AMI病例组的血浆同型半胱氨酸平均水平（18±8.36 μmol/l）高于对照组（16.4±4.9 μmol/l），但程度不显著。然而，正常健康受试者的这一同型半胱氨酸平均浓度是文献报道中最高的之一，且显著高于大多数东西方研究报道的平均值。与对照组相比，AMI患者中叶酸（分别为32.5%对67.1%）、B12（3.2%对63.4%）和PLP（49.2%对74.1%）的缺乏情况显著更严重。叶酸、B12和PLP缺乏的定义分别为血清叶酸水平低于3.5 ng/ml、血清B12水平低于200 pg/ml以及血浆PLP水平低于20 nmol/l。发现吸烟者的血浆同型半胱氨酸平均水平在病例组和对照组中均显著更高。同样，吸烟者（与不吸烟者相比）的血清叶酸平均水平在病例组和对照组中均显著更低。
这三种维生素存在大量营养缺乏以及轻度高同型半胱氨酸血症，可能通过与经典心血管危险因素（在该人群中高度流行）相互作用，进一步加重巴基斯坦人群患CAD的风险。
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