Mean Plasma Homocysteine Levels Research Articles

Relation of homocysteine levels with patency and flow rate of infarct related artery in patients receiving fibrinolytic therapy

Elevated homocysteine levels induce a hypercoagulable state and make the clot more resistant to fibrinolysis. In this prospective observational study, we investigated the influence of homocysteine levels on infarct-related artery (IRA) patency and flow as determined with regard to thrombolysis in myocardial infraction (TIMI) flow grade and corrected TIMI frame count (CTFC). Sixty-one patients who received fibrinolytic therapy for a first ST elevation myocardial infarction (STEMI) within 12 hours of chest pain were included. Coronary angiography was performed according to the Judkins technique within 72 hours after fibrinolytic therapy. Total plasma homocysteine level was determined by the high-performance liquid chromatography method with fluorescence detection. Statistical analysis was performed using Chi-square, Student's t and Pearson correlation tests. Logistic regression analysis was used to determine the predictors of IRA occlusion. Of the 61 patients, 22 (36.1%) had an occluded IRA (group 1), 39 (63.9%) had a patent IRA (group 2). Mean plasma homocysteine levels were found to be significantly higher in the group 1 compared to the group 2 (18.5±9.6 µmol/L vs 14.3±5 µmol/L, p=0.04). In addition, we found a significant positive correlation between CTFC and plasma homocysteine levels (r=0.415; p=0.01). In multiple logistic regression analysis, high levels of plasma homocysteine (OR=1.2; 95% CI 1.1-1.25; p=0.03) and being a non-smoker (OR=5.9; 95% CI 1.1-31.6; p=0.03) were found to be significant independent predictors of having an occluded IRA. There is an inverse relation between plasma homocysteine levels and IRA patency and flow in patients receiving fibrinolytic therapy for STEMI.

Association of Blood Lead (Pb) and Plasma Homocysteine: A Cross Sectional Survey in Karachi, Pakistan

BackgroundHigh blood lead (Pb) and hyperhomocysteinemia have been found to be associated with cardiovascular disease (CVD). Mean blood Pb and mean plasma homocysteine levels have been reported to be high in Pakistani population. The objective of the present study was to assess the relationship of blood Pb to the risk of hyperhomocysteinemia in a low income urban population of Karachi, Pakistan.Methodology/Principal FindingsIn a cross sectional survey, 872 healthy adults (355 males, 517 females; age 18–60 years) were recruited from a low income urban population of Karachi. Fasting venous blood was obtained and assessed for blood Pb and plasma/serum homocysteine, folate, pyridoxal phosphate (PLP, a coenzymic form of vitamin B6) and vitamin B12. The study population had median (IQR) blood Pb of 10.82 µg/dL (8.29–13.60). Prevalence of high blood Pb (levels >10 µg/dL) was higher in males compared to females (62.5% males vs 56% females; p value = 0.05). Mean ± SD/median (IQR) value of plasma homocysteine was significantly higher in the highest quartile of blood Pb compared to the lowest quartile 16.13±11.2 µmol/L vs 13.28±9.7µmol/L/13.15 (10.33–17.81) µmol/L vs 11.09 (8.65 14.31) µmol/L (p value<0.001). Daily consumption of fruit juice had a positive influence on both levels of plasma homocysteine and blood Pb. Compared with the lowest quartile of blood Pb, the OR for hyperhomocysteinemia was 1.69 (95% CI, 1.00 to 2.85) for the fourth quartile when the model was adjusted for age, gender, folate and vitamin B12.Conclusions/SignificanceThis study showed a relationship between blood Pb and hyperhomocysteinemia in a general population of Karachi, Pakistan. The harmful effect of Pb on cardiovascular system could be due to its association with hyperhomocysteinemia.

Homocysteine and folate levels as indicators of cerebrovascular accident

Homocysteinemia has been established as a risk factor for cardiovascular disorders by the American Heart Association.1 Cerebrovascular accident (stroke) is presently ranked as one of the leading causes of morbidity and mortality worldwide. The aim of this study was to determine homocysteine and folate levels and some basic hematologic parameters in patients who sustain a cerebrovascular accident and those who do not. In total, 100 participants were recruited, comprising 40 clinically diagnosed stroke (hemorrhagic or thromboembolic) patients and 60 healthy control subjects. Plasma homocysteine and folate levels were measured. Anticoagulated whole blood samples were evaluated for hemoglobin concentration (Hb), packed cell volume (PCV), white blood cell (WBC) count, and mean cell volume (MCV). The mean age of stroke patients was 62 ± 12 years and that of controls was 55 ± 18 years (P = 0.1756). Mean plasma homocysteine levels for stroke patients and controls were 17.7 ± 4.4 μmol/L and 9.5 ± 2.4 μmol/L, respectively (P = 0.0000) and mean plasma folate levels for the groups were 6.5 ± 2.9 μg/dL and 4.0 ± 2.4 μg/dL (P = 0.0407). The MCV for stroke patients was significantly higher than that for controls (85 fl versus 82 fl, P = 0.04). Mean homocysteine levels correlated inversely with Hb and PCV (r = -0.08 and r = -0.122, respectively) and weakly with WBC (P = 0.125). Homocysteinemia is a major predictor of cerebrovascular accident in the black Nigerian population.

Homocysteine Levels in Nigerian Women with Pre-eclampsis/Eclampsia

Hyperhomocysteinaemia has been linked in various studies worldwide to the occurrence of cardiovascular disorders and endothelial cell injury. In Nigeria with one of the highest maternal/neonatal mortality and morbidity, it is significant to explore means of predicting pregnancy-induced hypertension. This study was carried out at the Lagos University Teaching Hospital which is a major referral center in the South-western part of Nigeria. It was set to determine the mean plasma homocysteine levels and corpuscular haemoglobin in pre-eclamptic/eclamptic Nigerian women. A total of 150 subjects consisting of 100 primigravidae and 25 diagnosed cases of pre-eclampsia/eclampsia and 25 non-pregnant females were enrolled in the study. 60 primigravidae were lost to follow up or had incomplete data. The mean value of homocysteine in the control group, and eclamptic group was 7.5±3.4 μmol/L and 16.1±6.5 μmol/L respectively. There is positive and significant correlation between plasma homocysteine in the eclamptic group and the mean MCV (r=0.97, p=0.01), and between plasma homocysteine, systolic and diastolic blood pressure of the eclamptic group (r=0.944, p=0.0001; r=0.98, p=0.0001). The study further supports earlier findings of increased homocysteine levels in the occurrence of pre-eclampsia/eclampsia. Keywords: Hyperhomocysteinaemia, Pre-eclampsia/eclampsia, Primigravidae, Cardiovascular disorder

Vitamin B-12 Status Is Not Associated with Plasma Homocysteine in Parents and Their Preschool Children: Lacto-Ovo, Lacto, and Ovo Vegetarians and Omnivores

Objective: Vegetarians may be at risk of certain nutrient deficiencies, particularly vitamin B-12. Vitamin B-12 deficiency may increase plasma homocysteine concentration and thus may potentially increase the risk of cardiovascular disease in vegetarians. The purpose of this study was to assess and compare plasma homocysteine and vitamin B-12 status in vegetarian and omnivorous preschool children and their parents. In addition, the association between parents' and children's homocysteine and vitamin B-12 concentration was also examined.Methods: Fifty-six omnivores (28 preschool children and one of their parents), 34 lacto-ovo vegetarians (16 parents and 18 children), 5 ovo vegetarians (2 parents and 3 children), 1 lacto vegetarian parent, and 2 vegan parents were enrolled in this study. The mean age of preschool children was 5.1 ± 1.3 years and that of their parent was 35.4 ± 4.2 years. Nutrient intakes were recorded using 3-day dietary records. Fasting venous blood samples were obtained to measure serum creatinine, high-sensitivity C-reactive protein, hematological parameters, plasma homocysteine, serum folate, and vitamin B-12 concentrations.Results: There was no significant difference in dietary folate intake between vegetarian and omnivores within parent and child groups. The mean plasma homocysteine level of vegetarian parents and their children was in the physiological range, and they had slightly but not significantly higher plasma homocysteine levels than omnivores. Omnivorous parents and their children had significantly higher vitamin B-12 intake than vegetarian participants but similar serum vitamin B-12 concentrations. Plasma homocysteine concentration was significantly and negatively associated with only serum folate levels (β = −0.15) and dietary vitamin B-12 intake (β = −0.05) in the omnivorous parents after adjusting for age, gender, body mass index, and serum creatinine.Conclusion: Vegetarian parents and their preschool children had a lower vitamin B-12 intake than omnivorous parents and their preschool children but similar plasma vitamin B-12 and homocysteine concentrations. Plasma homocysteine was not associated with serum vitamin B-12 levels in the parent, child, or pooled group.

Effect of metformin and folic acid on plasma homocysteine level in type 2 diabetic patients

Hyperhomocysteinemia is associated with an increased risk of cardiovascular disease in diabetic patients. The aim of this study was to evaluate effects of metformin and folic acid on plasma homocysteine level in diabetic patients. In this clinical trial 47 new cases of type 2 diabetes were randomized to two groups. We treated patients in trial group with metformin and 1 mg folic acid, whereas patients in control group treated with metformin and placebo for 16 weeks. There was no significant difference in plasma homocysteine level and glycosylated hemoglobin (HbA1c) between two groups at the start of study. After 16 weeks plasma homocysteine level in the trial group did not change. In contrast plasma homocysteine level increased in the placebo group. There was significant difference in mean plasma homocysteine level between two groups (P-value < 0.01). This difference was highly significant in males (P-value < 0.0001). Correlation between glycosylated hemoglobin and plasma homocysteine level at start and end of study was not significant. This finding indicated that metformin increases plasma homocysteine level in diabetic patients especially males, whereas administration of folic acid with metformin can prevent this process.

Homocysteine and lipoprotein (a) correlation in ischemic stroke patients

Background Homocysteine and Lipoprotein (a) have been recognized as risk factors for coronary heart disease. However, their role in ischemic stroke is still not defined. Therefore the present study was undertaken to evaluate their levels and relationship in patients of ischemic stroke. Methods The study was conducted in consecutive patients admitted with a diagnosis of acute ischaemic stroke and age and sex matched healthy controls. Plasma homocysteine and serum l lipoprotein (a) levels were determined in the fasting venous blood samples using ELISA and immunoturbidimetric assay respectively. Results 66 patients with ischaemic stroke (30 males, 36 females) of mean age 54.43 ± 1.97 years and 72 controls (39 males, 33 females) of mean age 53.86 ± 1.88 years were studied. Mean plasma homocysteine levels in the stroke patients and control groups were 28.40 ± 2.08 µmol/L and 11.16 ± 1.09 µmol/L respectively ( p < 0.001). Odds ratio for raised homocysteine levels in stroke cases was 15.7. Plasma homocysteine levels showed a positive correlation with smoking (Pearson′s correlation coefficient = 0.324 and p-value of 0.008), (Odds ratio = 5.71). Serum Lipoprotein (a) levels in stroke cases and control group were 57.33 ± 4.40 mg/dl and 23.46 ± 1.09 mg/dl respectively, ( p < 0.001), (Odds Ratio = 8.62). A positive correlation was also observed between Homocysteine and Lipoprotein (a) levels with Pearson′s correlation coefficient of 0.75 and p-value < 0.001. Conclusions Raised homocysteine and serum lipoprotein (a) levels were found to be independently associated with ischemic stroke with a significant positive correlation between the two parameters. Elevated homocysteine levels may modulate the toxicity of lipoprotein (a) in ischemic stroke.

Plasma Homocysteine, MTHFR Gene Mutation, and Open-angle Glaucoma

Elevated plasma homocysteine has been associated with an increased risk of cardiovascular disease. The association between open-angle glaucoma and cardiovascular disease has recently stimulated interest in the role of homocysteine in the pathogenesis of glaucoma. Some studies report elevated plasma homocysteine in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma (PXFG), but have not found this association consistently in other types of open-angle glaucoma. In this study, we have measured plasma homocysteine and C677T methylenetetrahydrofolate reductase (MTHFR) mutation, the commonest genetic cause of elevated plasma homocysteine, in patients with PXFG, primary open-angle glaucoma (POAG), and normal tension glaucoma (NTG). Prospective cross-sectional cohort study. Forty-eight patients with PXFG, 36 patients with POAG, 34 patients with NTG, and 42 controls without glaucoma. Fasting venous blood samples from each participant were analyzed for plasma homocysteine and the C677T MTHFR gene mutation. MAIN OUTCOME OF INTEREST: Mean plasma homocysteine levels, number of individuals with homocysteine above the reference range, and percentage of individuals with heterozygous or homozygous C677T MTHFR gene mutations. Mean plasma homocysteine was significantly higher in PXFG (11.77+/-4.18 micromol/L), POAG (11.21+/-2.84 micromol/L), and NTG (11.74+/-3.79 micromol/L) compared with control (9.82+/-1.75 micromol/L). Hyperhomocysteinemia was found in 27.1% of PXFG patients, 30.6% of POAG patients, and 29.4% of NTG patients. There was no significant difference in frequency of MTHFR C677T gene mutation between groups. Plasma homocysteine was elevated in PXFG, POAG, and NTG. Elevated plasma homocysteine seems to be associated with glaucoma in these patients.

Hyperhomocysteinemia and retinal vascular changes in patients with epilepsy

The possible occurrence of asymptomatic retinal vascular damage was investigated in 87 hyperhomocysteinemic (plasma total homocysteine >13micromol/L) adult epileptic patients (46 M, 41 F; age 34.2+/-7.5 years; mean plasma homocysteine levels 29.8+/-15.4micromol/L; duration of epilepsy 11.5+/-2.4 years) with no other risk factors for atherosclerosis. Plasma total homocysteine (t-Hcy) levels were assayed by high performance liquid chromatography. Retina vascular status was assessed by fundus oculi ophthalmoscopy performed in blind conditions by two skilled ophthalmologists and compared with that obtained from 102 randomly chosen epileptic patients and 94 healthy subjects, matched for age and sex, showing normal t-Hcy levels. No retina abnormality was detected in any of the subjects belonging to the three groups. Based on these results, we conclude that epileptic patients with mild to intermediate hyperhomocysteinemia are not at risk to develop retinal vascular disease.

Effect of Folic Acid and B Vitamins on Risk of Cardiovascular Events and Total Mortality Among Women at High Risk for Cardiovascular Disease

Recent randomized trials among patients with preexisting cardiovascular disease (CVD) have failed to support benefits of B-vitamin supplementation on cardiovascular risk. Observational data suggest benefits may be greater among women, yet women have been underrepresented in published randomized trials. To test whether a combination of folic acid, vitamin B6, and vitamin B12 lowers risk of CVD among high-risk women with and without CVD. Within an ongoing randomized trial of antioxidant vitamins, 5442 women who were US health professionals aged 42 years or older, with either a history of CVD or 3 or more coronary risk factors, were enrolled in a randomized, double-blind, placebo-controlled trial to receive a combination pill containing folic acid, vitamin B6, and vitamin B12 or a matching placebo, and were treated for 7.3 years from April 1998 through July 2005. Daily intake of a combination pill of 2.5 mg of folic acid, 50 mg of vitamin B6, and 1 mg of vitamin B12. A composite outcome of myocardial infarction, stroke, coronary revascularization, or CVD mortality. Compared with placebo, a total of 796 women experienced a confirmed CVD event (406 in the active group and 390 in the placebo group). Patients receiving active vitamin treatment had similar risk for the composite CVD primary end point (226.9/10,000 person-years vs 219.2/10,000 person-years for the active vs placebo group; relative risk [RR], 1.03; 95% confidence interval [CI], 0.90-1.19; P = .65), as well as for the secondary outcomes including myocardial infarction (34.5/10,000 person-years vs 39.5/10,000 person-years; RR, 0.87; 95% CI, 0.63-1.22; P = .42), stroke (41.9/10,000 person-years vs 36.8/10,000 person-years; RR, 1.14; 95% CI, 0.82-1.57; P = .44), and CVD mortality (50.3/10,000 person-years vs 49.6/10,000 person-years; RR, 1.01; 95% CI, 0.76-1.35; P = .93). In a blood substudy, geometric mean plasma homocysteine level was decreased by 18.5% (95% CI, 12.5%-24.1%; P < .001) in the active group (n = 150) over that observed in the placebo group (n = 150), for a difference of 2.27 micromol/L (95% CI, 1.54-2.96 micromol/L). After 7.3 years of treatment and follow-up, a combination pill of folic acid, vitamin B6, and vitamin B12 did not reduce a combined end point of total cardiovascular events among high-risk women, despite significant homocysteine lowering. clinicaltrials.gov Identifier: NCT00000541.

Hyperhomocysteinemia and central retinal vein occlusion in Iranian population

To evaluate total plasma homocysteine level during the acute phase of central retinal vein occlusion (CRVO) in the Iranian population and determine whether hyperhomocysteinemia is also a risk factor for CRVO. Fifty-four patients with recently diagnosed CRVO were studied. Their fasting total plasma homocysteine level was compared with a matched control group of 51 patients evaluated in the same clinic for a non-retinal disease diagnosis. The mean total plasma homocysteine level was 14.76+/-7.67 micromol/l in cases, and 11.42+/-3.74 micromol/l in control subjects. It showed a significant difference (P=0.005) in mean plasma homocysteine level between cases and control group. Odds ratio of CRVO for individuals with hyperhomocysteinemia was 2.88 (95% CI=1.08-7.71 and P=0.03). The overall multivariable-adjusted odds of CRVO in participants with plasma homocysteine level above 15 micromol/l was 4.71 (95% CI=1.46-15.19 and P=0.009) Hyperhomocysteinemia was not statistically different in each age group (<60 years: 27%, 61-70 years: 33.3%, 71-80 years: 31.6%, >81 years: 33.3%, Chi-square test, P=0.98). Elevated total plasma homocysteine level is an independent risk factor for CRVO in Iranian population. In addition to an evaluation of all conventional cardiovascular risk factors, measurement of total homocysteine for evidence of hyperhomocysteinemia may be important in the initial investigation and management of patients with CRVO.

Homocisteína plasmática total e fator von Willebrand no diabete melito experimental

To determine the plasma homocysteine and von Willebrand factor levels as markers of endothelial dysfunction in rats with diabetes mellitus induced by streptozotocin. Thirty-five adult male rats (Rattus norvegicus albinus) (weight between 180-200 g) were randomized into three groups: control group (n=10), which received no drugs or vehicles; sham group (n=10), which received streptozotocin solution; and diabetic group (n=15), which received streptozotocin. Eight weeks after diabetes mellitus induction, the animals were weighed and anesthesized; blood samples were collected from abdominal aorta for plasma total homocysteine, von Willebrand factor and glucose levels. The experimental model was reproducible in 100% of animals. The mean plasma homocysteine levels were: 7.9 micromol/l (control), 8.6 micromol/l (sham) and 6.1 micromol/l (diabetic), with difference among the groups (p<0.01). Multiple comparison analysis among the groups showed that values in the diabetic group were lower than in the sham group (p<0.01). The mean von Willebrand factor values were 0.15 U/l (control), 0.16 U/l (sham) and 0.18 U/l (diabetic), with difference among the groups (p=0.03). The mean value was higher in the diabetic group than in the control group (p<0.05). Correlation between homocysteine and von Willebrand factor was not observed in the diabetic group. Reduced homocysteine levels and increased von Willebrand factor levels were observed in diabetes mellitus induced by streptozotocin; nevertheless, there were no correlations between them and with final glucose levels.

Hyperhomocysteinemia and the compound heterozygous state for methylene tetrahydrofolate reductase are independent risk factors for deep vein thrombosis among South Indians

To investigate the role of methylene tetrahydrofolate reductase (MTHFR) (677 C-->T and 1298 A-->C), factor V (1691 G-->A), factor II (20210 G-->A) genetic polymorphisms and hyperhomocysteinemia in the aetiology of deep vein thrombosis (DVT) in 163 cases and 163 controls. Polymerase chain reaction-restriction fragment length polymorphism was used for genotyping, reverse-phase high-performance liquid chromatography for plasma homocysteine, and Student's t-test and Fisher exact tests were used for statistical analysis. Elevated mean plasma homocysteine levels were observed in DVT cases irrespective of gender differences. Homocysteine elevation above the 95th percentile of the control group associated with 9.4-fold and 7.6-fold increased risk for DVT in men and women, respectively. Genotyping showed the MTHFR 677CT/1298AC genotype (i.e. compound heterozygosity) is associated with 3.5-fold risk for thrombosis. The factor V Leiden mutation frequency was higher in DVT cases, but not statistically significant; however, genetic predisposition to this mutation was associated with early age of DVT onset. Factor II mutation was absent in cases and controls. Co-segregation of two or more risk factors was associated with 11.7-fold increased risk for thrombosis. This study projects that hyperhomocysteinemia and compound heterozygous state for MTHFR are independent risk factors for DVT among South Indians.

B-Vitamin Status and Concentrations of Homocysteine in Austrian Omnivores, Vegetarians and Vegans

Background: A vegetarian diet is considered to promote health and longevity and reduce the risk of cardiovascular diseases and cancer. However, a vegetarian diet may be deficient in some nutrients. Exclusion of animal products in vegetarian diets may affect the status of certain B-vitamins, and further cause the rise of plasma homocysteine concentration. Objective: The nutritional status of various B-vitamins (B₁, B₂, B₆, B₁₂, folic acid) and the concentration of homocysteine in blood plasma of omnivores (n = 40), vegetarians (n = 36) and vegans (n = 42) in Austria was evaluated. Methods: The evaluation was done using the functional parameters erythrocyte transketolase (ETK), glutathione reductase (EGR) and glutamic oxaloacetic transaminase (EGOT) activation coefficients. Enzyme activity was measured photometrically. The quantity of vitamins B₁, B₂ and B₆ in urine and the concentrations of vitamin B₆ and homocysteine in plasma were determined by HPLC methods with fluorescence detection. Plasma concentration of vitamin B₁₂ and folic acid were measured with radioimmunoassay. Results: Most of the subjects showed a satisfying vitamin B₁ status. Vegans presented a significantly lower mean plasma vitamin B₁₂ concentration than omnivores and vegetarians and deficiency in 2.4% of the volunteers but the highest mean value of plasma folate among the investigated groups. A deficient status of folate was found in 18% of omnivores and in approximately 10% of vegans and vegetarians. The status of riboflavin is considered to be deficient in about 10% of omnivores and vegetarians and in over 30% of vegans. According to the activation coefficient of GOT, approximately one third of all subjects showed vitamin B₆ deficiency. Elevated homocysteine concentration in plasma was observed in 66% of the vegans and about 45–50% of the omnivores and vegetarians. Vegan subjects had significantly higher mean plasma homocysteine levels than omnivores. Conclusion: Thiamin and folate need not be a problem in a well-planned vegan diet. Vitamins B₁₂ and B₂ may need attention in the strict vegan diet, especially regarding elevated homocysteine levels in plasma. Pyridoxine status appeared to be independent of the diet.

Predictive Factors of Hyperhomocysteinemia in HIV-Positive Patients

Predictive Factors of Hyperhomocysteinemia in HIV-Positive Patients

Behavioural and Psychological Symptoms of Alzheimer Type Dementia Are Not Correlated with Plasma Homocysteine Concentration

Background/Aims: Vitamin B12 and folate deficiencies have been associated with cognitive impairment and various psychiatric symptoms but not specifically with behavioural and psychological symptoms of dementia (BPSD). A limitation of previous studies in dementia was lack of concurrent homocysteine measurement especially as it may provide a better indicator of tissue activities of these vitamins. This study was designed to clarify whether a relationship exists between plasma homocysteine concentration and BPSD. Methods: Plasma homocysteine, serum vitamin B12 and folate were measured in23Alzheimer’s disease (AD) patients with BPSD and 27 AD patients without BPSD as determined through the use of the Neuropsychiatric Inventory (NPI). Blood levels of measured substances were also correlated with individual NPI scores and with cumulative NPI scores for different cluster of symptoms. Results: There was no significant difference (p = 0.956) in the mean plasma homocysteine levels between AD patients with BPSD (17.48 µmol/l) and AD patients without BPSD (17.34 µmol/l). Similarly, there was no significant difference between the two groups in the mean serum B12 (382.61 and 391.60 pg/ml, respectively) and folate (7.95 and 10.02 ng/ml, respectively). Mean levels for both vitamins were well within the laboratory reference range. Neither individual nor cluster NPI scores correlated significantly with plasma homocysteine. Conclusion: This study shows for the first time that BPSD are not associated with hyperhomocysteinaemia in Alzheimer dementia. Although previous studies have identified homocysteine as an independent risk factor in AD, the results reported here do not lend weight to an aetiological role for homocysteine specifically in BPSD.

Homocysteine levels in adolescent schizophrenia patients

Homocysteine is a sulfur containing amino acid that has been widely investigated for its putative role in cardiovascular and neuropsychiatric disorders. It has been suggested that homocysteine has implications especially in young, male schizophrenia patients. In this prospective case-control study, we compared plasma homocysteine levels in a group of adolescent schizophrenia inpatients (aged 14–21 years; n=23) to normal healthy controls (n=51). Mean plasma homocysteine levels were significantly higher in the patient group than in the control group (15.40±2.00 and 9.78±0.33 μmol/L, respectively, p<0.032). The difference was almost entirely attributable to the male schizophrenia subgroup (18.18±5.65 in male patients vs. 10.31±5.33 μmol/L in female patients). The group×sex interaction was statistically significant (p=0.0035). These data indicate that a subgroup of male adolescent schizophrenia patients has high homocysteine blood levels. The role of homocysteine in the pathophysiology of adolescent-onset schizophrenia merits further investigation.

Cigarette smoking and cardiovascular risk factors among Aboriginal Canadian youths

Aboriginal populations in North America are exhibiting an increased prevalence of cardiovascular disease and associated traditional and nontraditional cardiovascular risk factors, trends believed to be due to the influence of Western lifestyle habits. Because these influences are present at an early age, we sought to study the patterns of one such habit, cigarette smoking, among Aboriginal Canadian youths and to assess the associated accrual of cardiovascular risk factors at an early age. Patterns of cigarette smoking were assessed in a population-based, cross-sectional study involving 236 youths aged 10-19 (mean 14.9) years in the Oji-Cree community of Sandy lake, in northwestern Ontario. Participants underwent clinical and metabolic evaluation with assessment of cardiovascular risk factors. The prevalence of cigarette smoking among the study participants was considerably higher than age-specific national averages, with fully 50% of the participants overall and 82% of the adolescent participants (aged 15-19) being current smokers. Compared with their peers, children smoking 6 or more cigarettes per day had an enhanced cardiovascular risk profile consisting of a higher mean systolic blood pressure (111 v. 107.5 mm Hg, p = 0.036), a higher mean plasma homocysteine level (8.7 v. 7.6 micromol/L, p = 0.008) and a lower mean serum folate level (4.5 v. 5.4 mmol/L, p = 0.007), after adjustment for age, sex and body mass index. In separate multiple linear regression analyses, current cigarette exposure (number of cigarettes smoked per day) emerged as an independent determinant of both systolic blood pressure and plasma homocysteine level. In this Aboriginal community with remarkably high rates of cigarette smoking among its youth, an independent dose-response relation was found between current smoking exposure and both traditional (systolic blood pressure) and nontraditional (homocysteine level) cardiovascular risk factors. The association of cigarette smoking with an enhanced cardiovascular risk profile at an early age may be a factor contributing to the high prevalence of cardiovascular disease in this Aboriginal population.

Hyperhomocysteinaemia as a Risk Factor for Deep-vein Thrombosis

ObjectiveSeveral studies have shown a relation between hyperhomocysteinaemia and vascular disease. To assess the risk of deep-vein thrombosis (DVT) associated with hyperhomocysteinaemia, we studied plasma homocysteine levels in patients with deep-vein thrombosis and in normal control subjects. Materials and methodsWe measured plasma homocysteine levels in 48 patients with deep-vein thrombosis and in 33 healthy controls matched to the patients according to age and sex. Plasma homocysteine levels were measured with high performance liquid chromatography and fluorescence detection. Hyperhomocysteinaemia was defined as a plasma homocysteine level about 15μmol/L in both groups. The diagnosis of all patients with deep-vein thrombosis (n=48) was verified by Doppler ultrasonography. ResultsPlasma homocysteine levels were found to be increased in the deep-vein thrombosis group compared the control group (p<0.001, t-test). The mean plasma homocysteine level in the patients was 17.1 SD 5.13μmol/L (range 6.4–31.3), and that in the controls was 9.0 SD 1.27μmol/L (range 6.0–11.5).The association between elevated homocysteine levels and venous thrombosis was stronger among men than among women. ConclusionsThe increased plasma homocysteine levels we have observed may have a causative role in the development of deep-vein thrombosis.

Role of vitamins B6, B12 and folic acid on hyperhomocysteinemia in a Pakistani population of patients with acute myocardial infarction

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.