Total homocysteine, folate, and cobalamin, and their relation to genetic polymorphisms, lifestyle and body mass index in healthy children and adolescents

Serum binding folate receptor autoantibodies lower in autistic boys and positively-correlated with folate

Folate receptor autoantibody (FRAA) has caught increasing attention since its discovery in biological fluids of patients with autism spectrum disorder (ASD), but quantification and understanding of its function are still in their infancy. In this study, we aimed to quantify serum binding-FRAA and explore its relation with serum folate, vitamin B12 (VB12) and ferritin. We quantitated serum binding-FRAA in 132 ASD children and 132 typically-developing (TD) children, as well as serum levels of folate, VB12 and ferritin. The results showed that serum binding-FRAA in the ASD group was significantly lower than that in the TD group (p < 0.0001). Further analysis showed that the difference between these two groups was attributed to boys in each group, not girls. There was no statistically significant difference in folate levels between the ASD and TD groups (p > 0.05). However, there was significant difference in boys between these two groups, not girls. Additionally, the combination of nitrite and binding-FRAA showed potential diagnostic value in patients with ASD (AUC > 0.7). Moreover, in the ASD group, the level of folate was consistent with that of binding-FRAA, whereas in the TD group, the binding-FRAA level was high when the folate level was low. Altogether, these differences revealed that the low serum FRAA in autistic children was mediated by multiple factors, which deserves more comprehensive investigation with larger population and mechanistic studies.

Plasma homocysteine levels and associated factors in community-dwelling adolescents: the EVA-TYROL study

Background

Homocysteine (Hcy) has been associated with an adverse cardiovascular risk profile in adolescents. Assessment of the association between plasma Hcy levels and clinical/laboratory factors might improve our understanding of the pathogenesis of cardiovascular disease.

Methods

Hcy was measured in 1,900 14- to 19-year-old participants of prospective population-based EVA-TYROL Study (44.3% males, mean age 16.4 years) between 2015 and 2018. Factors associated with Hcy were assessed by physical examination, standardized interviews, and fasting blood analysis.

Results

Mean plasma Hcy was 11.3 ± 4.5 µmol/L. Distribution of Hcy was characterized by extreme right skew. Males exhibited higher Hcy and sex differences increased with increasing age. Univariate associations with Hcy emerged for age, sex, body mass index, high-density lipoprotein cholesterol, and for factors pertaining to blood pressure, glucose metabolism, renal function, and diet quality, whereas the most important multivariate predictors of Hcy were sex and creatinine.

Discussion

Clinical and laboratory factors associated with Hcy in adolescents were manifold, with sex and high creatinine identified as strongest independent determinants. These results may aid when interpreting future studies investigating the vascular risk of homocysteine.

Daily Folic Acid and/or Vitamin B12 Supplementation Between 6 and 30 Months of Age and Cardiometabolic Risk Markers After 6-7 Years: A Follow-Up of a Randomized Controlled Trial

BACKGROUND

Deficiencies of vitamin B12 and folate are associated with elevated concentrations of metabolic markers related to CVDs.

OBJECTIVES

We investigated the effect of supplementation of vitamin B12 with or without folic acid for 6 mo in early childhood on cardiometabolic risk markers after 6-7 y.

METHODS

This is a follow-up study of a 2 × 2 factorial, double-blind, randomized controlled trial of vitamin B12 and/or folic acid supplementation in 6-30-mo-old children. The supplement contained 1.8 μg of vitamin B12, 150 μg of folic acid, or both, constituting >1 AI or recommended daily allowances for a period of 6 mo. Enrolled children were contacted again after 6 y (September 2016-November 2017), and plasma concentrations of tHcy, leptin, high molecular weight adiponectin, and total adiponectin were measured (N = 791).

RESULTS

At baseline, 32% of children had a deficiency of either vitamin B12 (<200 pmol/L) or folate (<7.5 nmol/L). Combined supplementation of vitamin B12 and folic acid resulted in 1.19 μmol/L (95% CI: 0.09; 2.30 μmol/L) lower tHcy concentration 6 y later compared to placebo. We also found that vitamin B12 supplementation was associated with a lower leptin-adiponectin ratio in subgroups based on their nutritional status.

CONCLUSIONS

Supplementation with vitamin B12 and folic acid in early childhood was associated with a decrease in plasma tHcy concentrations after 6 y. The results of our study provide some evidence of persistent beneficial metabolic effects of vitamin B12 and folic acid supplementation in impoverished populations. The original trial was registered at www.

CLINICALTRIALS

gov as NCT00717730, and the follow-up study at www.ctri.nic.in as CTRI/2016/11/007494.

The role of the deficiency of vitamin B12 and folic acid on homocysteinemia in children with Turner syndrome

OBJECTIVES

Premature atherosclerosis and ischemic heart disease represent a major cause of comorbidities among children with Turner syndrome. The identification of non-traditional risk aspects is crucial for the early identification and management of such comorbidities through establishing effective preventive measures. The aim of the study is to explore the role of the deficiency of vitamin B12, folic acid and homocysteine in children with Turner syndrome.

METHODS

The study included 78 children with Turner syndrome and 67 healthy age and sex matched children. Karyotype was implemented for all patients. The serum levels of vitamin B12, folic acid and serum homocysteine were assessed. The prevalence of the deficiency of vitamin B12 and folic acid was estimated to study its correlation to hyperhomocysteinemia in Turner syndrome children.

RESULTS

The karyotype analysis showed 45,X (monosomy X) in the 78 patients. Vitamin B12 and folic acid were significantly decreased in children with Turner syndrome in 65-73% of the patients, respectively, while the serum level of homocysteine significantly increased to 48.7% compared to healthy controls. Homocysteine level negatively correlated with vitamin B12 and folic acid. The deficiency of vitamin B12 and folic acid increased the risk of hyperhomocysteinemia in children with Turner syndrome (OR 2.49 and 2.36, respectively).

CONCLUSIONS

This report highlights that hyperhomocyste-inemia in children with Turner syndrome may be related to the deficiency vitamin B12 and folic acid.

Serum pyridoxine, folate, cobalamin, and homocysteine levels in children presenting with vasovagal syncope

BACKGROUND

Recent studies confirm the role of B vitamins deficiency and hyperhomocysteinaemia in the development of dysautonomia that has been considered to be the main factor in vasovagal syncope development. The aim of the study was to investigate serum pyridoxine, folate, cobalamin, and homocysteine levels in children presenting with vasovagal syncope and to analyse the correlation between them and main clinical parameters of syncope.

METHODS

We studied 40 children, ages 8-17 years with a history of vasovagal syncope and 24 healthy volunteers. The serum pyridoxine, folate, cobalamin, and homocysteine levels were measured by a quantitative sandwich enzyme immunoassay technique using a commercial kit (Monobind, USA). Twenty-four-hour Holter monitoring and 24-hour ambulatory blood pressure monitoring were conducted for all participated patients.

RESULTS

Serum pyridoxine (9.42 ± 4.87, 16.11 ± 5.53 µg/L) and cobalamin (307.48 ± 95.50, 447.28 ± 108.85 ng/L) levels were reasonably low (p < 0.05) in patients with vasovagal syncope. Although there was no significant change in folate levels between syncope and healthy children (4.00 ± 1.34, 4.71 ± 1.73 µg/L; p = 0.20), we detected low folate-level association with longer duration of syncope (r = -0.42) and post syncope (r = -0.43) symptoms (p < 0.05). Finally, there was increased serum homocysteine level (13.55 ± 5.03, 7.81 ± 1.71 µmol/L; p < 0.05) in patients with vasovagal syncope. It was positively correlated with the average PQ interval (r = 0.35, p < 0.05) and average QTc interval (r = 0.49, p < 0.05).

CONCLUSIONS

The results suggested that pyridoxine, folate, cobalamin, and homocysteine may be involved in the pathogenesis of vasovagal syncope. This might provide a new approach for effective treatment of paediatric vasovagal syncope, requiring further study.

Adolescent Afghan Refugees Display a High Prevalence of Hyperhomocysteinemia and Associated Micronutrients Deficiencies Indicating an Enhanced Risk of Cardiovascular Disease in Later Life

A growing body of research evidence suggests that elevated homocysteine level (hyperhomocysteinemia) is an independent risk factor for cardiovascular diseases. The current study aimed to investigate the prevalence and associated risk factors for hyperhomocysteinemia among adolescent Afghan refugees aged 10−19 years. In total, 206 healthy adolescent boys and girls were randomly recruited from a refugee village in Peshawar, Pakistan, in 2020. Socio-demographic data, anthropometric assessment, and blood sample collection were performed following standard methods. Serum homocysteine was assessed using a chemiluminescent microparticle immunoassay, with hyperhomocysteinemia defined as levels ≥ 15 µmol/L. The overall prevalence of hyperhomocysteinemia was 25%, with mean homocysteine levels significantly (p = 0.004) higher among boys (14.1 µmol/L) than girls (11.8 µmol/L). Multivariate logistic regression analysis revealed a significant association between hyperhomocysteineimia and serum levels of vitamin B12 (OR 0.29; 95% CI of 0.14 to 0.62; p < 0.01) and folate (OR 0.1; 95% CI of 0.03 to 0.27; p < 0.001). Overall, our study findings indicate high prevalence of hyperhomocysteinemia among adolescent Afghan refugees who are potentially at high risk of developing cardiovascular diseases in future. There is a dire need to develop and implement nutritional and public health strategies to control hyperhomocysteinemia, protect against related diseases and complications in future, and ensure healthy lives and well-being among these vulnerable populations.

Association of Obesity with the Risk of Hyperhomocysteinemia among the Chinese Community Residents: A Prospective Cohort Study in Shanghai, China

A prospective community-based cohort study was conducted to investigate the effects of obesity on hyperhomocysteinemia (HHcy) in community residents from Shanghai, China, with a median follow-up period of 2.98 years. The exposures were high body mass index (BMI) (BMI ≥ 28.0 kg/m²) and high waist circumference (WC) (WC ≥ 85.0 cm for female and WC ≥ 90.0 for male) at baseline investigation, and the outcome was the incident of HHcy after the follow-up. A restricted cubic spline (RCS) was performed to assess the possible nonlinear relationship of BMI and WC with HHcy. A Cox proportional hazard regression model was used to evaluate the association between BMI and WC measured obesity and the risk of HHcy (Hcy level > 15 µmol/L). No significant non-linearity was found between BMI and WC with HHcy. Cox regression model showed that underweight measured by BMI was negatively associated with the risk of HHcy after controlling for confounder variables (adjusted HR = 0.64, 95% CI = 0.42 to 0.99). While abdominal obesity was positively associated with the risk of HHcy for those without CVD-related comorbidities (adjusted HR = 1.26, 95% CI = 1.05 to 1.51). Our results suggested that individuals could maintain a relatively low BMI and normal WC to lower the risk of HHcy.

Folate and Cobalamin Serum Levels in Healthy Children and Adolescents and Their Association with Age, Sex, BMI and Socioeconomic Status

This study proposes age- and sex-specific percentiles for serum cobalamin and folate, and analyzes the effects of sex, age, body mass index (BMI), and socioeconomic status (SES) on cobalamin and folate concentrations in healthy children and adolescents. In total, 4478 serum samples provided by healthy participants (2 months-18.0 years) in the LIFE (Leipzig Research Centre for Civilization Diseases) Child population-based cohort study between 2011 and 2015 were analyzed by electrochemiluminescence immunoassay (ECLIA). Continuous age-and sex-related percentiles (2.5th, 10th, 50th, 90th, 97.5th) were estimated, applying Cole's LMS method. In both sexes, folate concentrations decreased continuously with age, whereas cobalamin concentration peaked between three and seven years of age and declined thereafter. Female sex was associated with higher concentrations of both vitamins in 13- to 18-year-olds and with higher folate levels in one- to five-year-olds. BMI was inversely correlated with concentrations of both vitamins, whilst SES positively affected folate but not cobalamin concentrations. To conclude, in the assessment of cobalamin and folate status, the age- and sex-dependent dynamic of the respective serum concentrations must be considered. While BMI is a determinant of both vitamin concentrations, SES is only associated with folate concentrations.

Serum Homocysteine and Cysteine Levels and Anthropometric Changes: A Longitudinal Study among Brazilian Children and Adolescents

OBJECTIVE

This article aimed to identify the influence of high serum homocysteine (Hcy) and cysteine (Cys) levels, alone or in conjunction, on changes in anthropometric parameters in children and adolescents over a 12-month follow-up period.

METHODS

This is a cohort study involving 483 boys and girls 7-15 years of age. The outcome variables were body mass index (BMI)-for-age and waist circumference (WC) and the principal exposure variables were serum Hcy and Cys levels, alone or in conjunction. A generalized estimating equation (GEE) approach was used to identify longitudinal changes in the outcome variables.

RESULTS

Irrespective of age, sex, socioeconomic conditions, dietary intake, or the practice of physical activity, the children and adolescents in the fifth quintile of distribution of Hcy levels had a z-score increase of 0.50 (p < 0.01) and a 3.62 cm increase (p < 0.01) in mean BMI-for-age and WC, respectively, over the period of the study. In individuals with Cys values above the fifth quintile, a z-score increase of 0.59 (p < 0.01) and a 5 cm increase (p < 0.01) were found in BMI-for-age and WC, respectively. When serum Hcy and Cys levels were both above the fifth quintile of distribution, a z-score increase of 0.87 (p < 0.01) and a 6.57 cm increase (p < 0.01) were found in mean BMI-for-age and WC, respectively, over the 12-month follow-up.

CONCLUSION

High serum Hcy and Cys levels contributed to an increase in BMI-for-age and WC in children and adolescents over a 12-month follow-up period, with these increases being even greater when these 2 biochemical parameters were simultaneously high.

A Prospective Study of Homocysteine and its relation to Body Mass Index and Lipid Profile in School Children

OBJECTIVE

To study the serum Homocysteine levels in children and its relation with body mass index (BMI), lipid profile and plasma glucose.

Methods

138 children (age 5-15 y) were enrolled and categorized into normal, overweight and obese group. Blood homocysteine, lipid profile and plasma glucose were estimated.

RESULTS

Out of 138 children, 46 (33%) were normal, 40 (29%) were overweight and 52 (38%) were obese. Hyper-homocysteinemia was found in 34 (24.6%) of children. None of the normal children had hyperhomocysteinemia in contrast to 15 (37.5%) in overweight and 19 (36.5%) in obese group (P=0.001).The median homocysteine levels in obese and overweight children was significantly higher compared to normal children (P=0.001).There was a positive correlation between BMI and homocysteine levels. There was no significant correlation between lipid profile and plasma glucose with homocysteine levels.

CONCLUSION

Serum homocysteine levels are significantly higher in both overweight and obese children compared to normal children.

Hyperhomocysteinemia Is Associated with Vitamin B-12 Deficiency: A Cross-sectional Study in a Rural, Elderly Population of Shanxi China

OBJECTIVES

To report the association of lifestyle factors and plasma vitamin B-12 with hyperhomocysteinemia in a large sample of men and women living in a region of China where there is an increased risk of NTDs.

DESIGN

Community-based, cross-sectional study of Lvliang City, Shanxi Province, China.

SETTING

Hyperhomocysteinemia is an independent risk factor for cardiovascular disease (CVD) and a sensitive marker of vitamin B-12 and folate deficiency.

PARTICIPANTS

A total of 2355 (1044 men and 1311 women) participants born before 1 January 1958 (≥55 years of age) and living in Lvliang City for at least 2 months a year were included.

MEASUREMENTS

The participants were assessed regarding demographic characteristics, height, weight, as well as having a physical examination and blood sampling for serum cholesterol, total homocysteine (tHcy), folate, and vitamin B12 levels.

RESULTS

The median (25th-75th percentile) tHcy concentration was 21.5 (15.8-33.6) µmol/L in men and 18.0 (13.4-24.8) µmol/L in women. The overall prevalence of hyperhomocysteinemia (tHcy ≥15 µmol/L) was 72.6% (84.3% in men and 63.2% in women), inversely correlated with folate (r=-0.230, P=0.006) and vitamin B-12 (r=-0.540, P<0.001), and positively correlated with uric acid (r=0.054, P<0.001). Vitamin B-12 and folate deficiency, older age, and male gender were associated with elevated tHcy; with vitamin B-12 deficiency being the strongest.

CONCLUSIONS

Plasma tHcy concentration and hyperhomocysteinemia were significantly higher in this population than in previously studied populations. Vitamin B-12 and folate supplementation, concomitant lifestyle changes such as smoking cessation, and lipid-lowering treatments may help to decrease plasma tHcy concentrations and reduce the CVD risk in this population.

Dietary Intakes of Folic Acid and Methionine in Early Childhood Are Associated with Body Composition at School Age

BACKGROUND

Deficiency of vitamin B-6, vitamin B-12, folate, folic acid, or methionine may lead to dysregulation of DNA methylation, which might lead to disturbed energy and lipid metabolism.

OBJECTIVE

We aimed to explore whether intakes of vitamin B-6, vitamin B-12, folate, folic acid, and methionine at 1 y are associated with measures of growth and body composition at the age of 6 y.

METHODS

This study was performed in 2922 children participating in The Generation R Study, a population-based prospective cohort study. Dietary intakes of vitamins B-6 and B-12, folate, folic acid, and methionine were assessed at a median age of 12.9 mo by using a validated food-frequency questionnaire. At the age of 6 y, height and weight were measured, and body mass index (BMI; in kg/m(2)) was calculated. Body fat was measured with dual-energy X-ray absorptiometry, and body fat percentage and the ratio of android fat mass to gynoid fat mass (android:gynoid) were calculated.

RESULTS

In models adjusted for maternal and child characteristics, children with folic acid intakes in the highest tertile had a 0.16 SD score (SDS) lower weight (95% CI: -0.31, -0.02 SDS) and a 0.14 SDS lower BMI (95% CI: -0.26, -0.01 SDS) than children in the lowest tertile. Children with vitamin B-12 intakes in the highest tertile had a 0.13 SDS higher android:gynoid (95% CI: 0.00, 0.25 SDS) than children in the lowest tertile. In addition, children with intakes in the highest tertile of methionine had a 0.09 SDS higher BMI (95% CI: 0.01, 0.17) and a 0.12 SDS higher android:gynoid (95% CI: 0.02, 0.22) than children in the lowest tertile. Vitamin B-6 and folate intakes were not associated with any of the body composition outcomes measured.

CONCLUSIONS

In this population of children, early high folic acid intakes were associated with a lower body weight and BMI at the age of 6 y. In contrast, early higher methionine intakes were associated with unfavorable body composition at the age of 6 y. Future studies should investigate long-term consequences of these outcomes on health.

Genetic and environmental factors associated with vitamin B12status in Amazonian children

Objective

To evaluate the prevalence of vitamin B12deficiency and factors associated with vitamin B12status in Amazonian children.

Design

Genetic risk score (GRS), socio-economic and nutritional status, and morbidity data were the independent variables used in multiple linear regression models to evaluate factors associated with vitamin B12status in a population-based cross-sectional study. GRS was created by summing a number of known risk alleles for low serum vitamin B12.

Setting

Acrelândia, western Brazilian Amazon.

Subjects

Children (n988) aged <10 years.

Results

Overall prevalence of vitamin B12deficiency (<150 pmol/l) was 4·2 (95 % CI 3·0, 5·6) % and was highest in children aged <24 months: 13·6 (95 % CI % 8·8, 19·7) %. For children <24 months, wealth index (β=0·017,P=0·030) and animal protein intake(β=0·219,P=0·003) were positively associated with vitamin B12status. GRS (β=−0·114,P<0·001) and serum homocysteine (β=–0·049,P<0·001) were negatively associated. Among children aged ≥24 months, vitamin B12status was positively associated with wealth index (β=0·012,P<0·001), height-for-ageZ-score (β=0·024, P=0·033) and serum vitamin A (β=0·089,P<0·001). Age≥60 months(β=–0·118,P<0·001), GRS (β=–0·048, P<0·001), maternal schooling <5 years (β=–0·083,P<0·001), low intake of animal-derived foods (β=–0·050,P=0·030), serum homocysteine (β=–0·053,P<0·001), serum folate ≥23·6 nmol/l (β=–0·055,P=0·012) and geohelminth infection (β=–0·141,P=0·017) were negatively associated with vitamin B12status.

Conclusions

GRS, poverty, low intake of animal-derived foods, geohelminth infection, vitamin A and folate status were important factors associated with vitamin B12status of children in our study.

MTHFR polymorphisms and serum cobalamin affect plasma homocysteine concentrations differentially in females and males

A total of 523 subjects (297 females and 226 males) from the Canary Islands Nutrition Study (ENCA) were studied in order to examine the effect of the MTHFR 677C>T, 1298A>C and 1793G>A polymorphisms, adjusted for age, serum (S)‑folate and S‑cobalamin levels, on total plasma homocysteine concentrations (tHcy). Genotyping was performed with Pyrosequencing® technology. The MTHFR 677T‑allele was associated with increased tHcy concentrations only in males (P=0.005). The MTHFR 1298C‑allele was found to be associated with higher tHcy levels but similarly, only in males (P=0.025). The MTHFR 1793A‑allele was associated with decreased tHcy concentrations in the younger males (P=0.042). A haplotype‑based approach was marginally superior in explaining the genetic interaction of the MTHFR polymorphisms on tHcy plasma levels (R2 0.352 vs. 0.342 for a simple genotype‑based approach). A nutrigenetic interaction between the MTHFR 677C>T genotype and S‑cobalamin on tHcy levels was demonstrated in both genders. The increase in tHcy was more pronounced with decreasing S‑cobalamin quintiles in 677TT homozygotes (P=0.005 for males and P=0.015 for females) than with decreasing S‑folate quintiles (P for trend not significant). It was concluded that gene‑nutrient interactions may differ depending on the sex and age of the subjects. The transferability of gene‑nutrient interactions from one community to others may therefore be limited not only by different food patterns but also by different ages, genders and genotype distributions.

Folic acid supplementation on homocysteine levels in children taking antiepileptic drugs: A randomized controlled trial

OBJECTIVES

To assess the level of homocysteine (tHcy) in children taking AEDs and to study whether daily oral supplementation of folic acid for 1 month will reduce the tHcy level.

MATERIALS AND METHODS

This was a double-blinded, randomized control trial conducted in Institute of Maternal and Child Health, Kozhikode, India. Totally 60 children were recruited and of them, 48 were enrolled. Of these children, 32 were assigned to the experimental group and 16 to the control group. Baseline data collection and tHcy estimation were done. One mg folic acid tablets were given to the experimental group and placebo tablets to the control group for 30 days. tHcy levels were re-estimated after 1 month follow-up. Statistical significance was tested by χ(2) test, and paired and unpaired t-tests, as appropriate. Correlation was tested by Pearson correlation test and P value less than 0.05 was taken as the cut-off for statistical significance.

RESULTS

Baseline plasma tHcy concentrations in both groups were comparable [11.90 (6.3) and 13.02 (2.4) μmol/l, respectively]. During the follow-up period, no increase in seizure episodes or no serious adverse reactions were noticed in either group. The reduction of tHcy in the experimental group was 1.92 μmol/l (P = 0.04) and in the control group, there was an increase of 1.05 μmol/l (P = 0.16).

CONCLUSIONS

In children on AED treatment, folic acid supplementation may reduce tHcy level and thus reduce CVD risk.

Three-month B vitamin supplementation in pre-school children affects folate status and homocysteine, but not cognitive performance

BACKGROUND

Suboptimal vitamin B status might affect cognitive performance in early childhood. We tested the hypothesis that short-term supplementation with folic acid and selected B vitamins improves cognitive function in healthy children in a population with relatively low folate status.

METHODS

We screened 1,002 kindergarten children for suboptimal folate status by assessing the total urinary para-aminobenzoylglutamate excretion. Two hundred and fifty low ranking subjects were recruited into a double blind, randomized, controlled trial to receive daily a sachet containing 220 μg folic acid, 1.1 mg vitamin B2, 0.73 mg B6, 1.2 μg B12 and 130 mg calcium, or calcium only for 3 months. Primary outcomes were changes in verbal IQ, short-term memory and processing speed between baseline and study end. Secondary outcomes were urinary markers of folate and vitamin B12 status, acetyl-para-aminobenzoylglutamate and methylmalonic acid, respectively, and, in a subgroup of 120 participants, blood folate and plasma homocysteine.

RESULTS

Pre- and post-intervention cognitive measurements were completed by 115 children in the intervention and 122 in the control group. Compared to control, median blood folate increased by about 50% (P for difference, P < 0.0001). Homocysteine decreased by 1.1 μmol/L compared to baseline, no change was seen in the control group (P for difference P < 0.0001) and acetyl-para-aminobenzoylglutamate was 4 nmol/mmol higher compared to control at the end of the intervention (P < 0.0001). We found no relevant differences between the groups for the cognitive measures.

CONCLUSION

Short-term improvement of folate and homocysteine status in healthy children does not appear to affect cognitive performance.

Study of pattern of dyslipidemia and its correlation with cardiovascular risk factors in patients with proven coronary artery disease

INTRODUCTION

Dyslipidemia is a primary, widely established as an independent major risk factor for coronary artery disease (CAD). Asians differs in prevalence of various lipid abnormalities than non-Asians. Hence, this study was conducted with objective to evaluate the lipid abnormalities and there correlation with traditional and non-traditional risk factors in known subjects with CAD.

MATERIALS AND METHODS

We studied the pattern and association of dyslipidemia with cardiovascular risk factors in 300 (Male: 216; Female: 84, age: 60.9 ± 12.4 years, range: 25-92 years) angiographically proved CAD patients. All patients were evaluated for anthropometry and cardiovascular risk factors and blood samples were collected for biochemical and inflammatory markers.

RESULTS

Hypercholesterolemia, hypertriglyceridemia and low high density lipoprotein (HDL) was present in 23.3%, 63.0% and 54.6% in the total study population respectively. A total of 41.3% had atherogenic dyslipidemia (raised triglycerides [TG] and low HDL). Percentage of patients with type-2 diabetes mellitus and hypertension were higher in subjects with atherogenic dyslipidemia. Insulin sensitivity was low; insulin and insulin resistance (IR) along with inflammatory markers were high in subjects with atherogenic dyslipidemia. Patients with atherogenic dyslipidemia had significantly lower serum vitamin B12 levels and higher homocysteine (Hcy) levels. Hypertriglyceridemia was positively correlated with insulin, homeostasis model assessment of IR, Hcy, interleukin-6, Tumor necrosis factor-alpha, highly sensitive C-reactive protein and negatively with vitamin B12 and quantitative insulin check index and an opposite correlation of all quoted parameters was observed with low HDL. The correlation of traditional and non-traditional risk factors was stronger with low HDL and high TG compared with hypercholesterolemia.

CONCLUSIONS

Hypertriglyceridemia and low HDL cholesterol is common in patients with CAD compared with hypercholesterolemia. This suggests that different preventive strategy is required in Indian patients with CAD.

Folate, vitamin B₁₂ and total homocysteine levels in Arab adolescent subjects: reference ranges and potential determinants

BACKGROUND & AIMS

Elevated circulating fasting total homocysteine (tHcy) concentration is associated with an increased risk of occlusive vascular disease in adults. Important determinants of tHcy levels are folate, vitamin B(12) and vitamin B(6). This study aimed to investigate age, gender, and body mass as determinants of folate, vitamin B(12) and tHcy levels in Arab older children and adolescents and to propose population, gender and age-specific reference ranges for these biomarkers.

METHODS & RESULTS

774 (316 boys, 458 girls) healthy 10-19 yr olds attending secondary schools in Kuwait were assessed for anthropometry and fasting blood levels of Hcy, folate and vitamin B(12). The mean (95% CI) serum levels of tHcy, folate and vitamin B(12) were respectively 6.57 μmol/L (6.42-6.73), 16.0 ng/ml (15.6-16.3) and 354.3 pg/ml (343.0-365.7). Boys had significantly higher tHcy and folate concentrations than the girls, although vitamin B(12) levels were greater in the latter. Folate and vitamin B(12) levels decreased significantly with age, while correspondingly, tHcy levels increased, with mean values (μmol/L) for boys (6.71; 8.25) and girls (5.36; 6.67) aged 10-14 yr and 14-19 yr respectively. Bivariate and multivariate analyses with adjustment for confounders such as age, gender, need for dietary control and socio-demographic variables indicated that the independent determinants of levels of tHcy were age, gender and body mass.

CONCLUSION

There is an age-related increase in tHcy in adolescents reflecting decreased levels of folate and vitamin B(12), with the suggestion that age-related reference ranges for these biomarkers be used. These observations may have implications for prevention of future atherogenic disease.

Cognitive impairment and vitamin B12: a review

BACKGROUND

This review examines the associations between low vitamin B12 levels, neurodegenerative disease, and cognitive impairment. The potential impact of comorbidities and medications associated with vitamin B12 derangements were also investigated. In addition, we reviewed the evidence as to whether vitamin B12 therapy is efficacious for cognitive impairment and dementia.

METHODS

A systematic literature search identified 43 studies investigating the association of vitamin B12 and cognitive impairment or dementia. Seventeen studies reported on the efficacy of vitamin B12 therapy for these conditions.

RESULTS

Vitamin B12 levels in the subclinical low-normal range (<250 ρmol/L) are associated with Alzheimer's disease, vascular dementia, and Parkinson's disease. Vegetarianism and metformin use contribute to depressed vitamin B12 levels and may independently increase the risk for cognitive impairment. Vitamin B12 deficiency (<150 ρmol/L) is associated with cognitive impairment. Vitamin B12 supplements administered orally or parenterally at high dose (1 mg daily) were effective in correcting biochemical deficiency, but improved cognition only in patients with pre-existing vitamin B12 deficiency (serum vitamin B12 levels <150 ρmol/L or serum homocysteine levels >19.9 μmol/L).

CONCLUSION

Low serum vitamin B12 levels are associated with neurodegenerative disease and cognitive impairment. There is a small subset of dementias that are reversible with vitamin B12 therapy and this treatment is inexpensive and safe. Vitamin B12 therapy does not improve cognition in patients without pre-existing deficiency. There is a need for large, well-resourced clinical trials to close the gaps in our current understanding of the nature of the associations of vitamin B12 insufficiency and neurodegenerative disease.

Congenital heart defects and biomarkers of methylation in children: a case-control study

BACKGROUND

Derangements in the maternal methylation pathway, expressed by global hypomethylation and hyperhomocysteinemia, are associated with the risk of having a child with a congenital heart defect (CHD). It is not known whether periconception exposure to these metabolic derangements contributes to chromosome segregation and metabolic programming of this pathway in the foetus.

DESIGN

In a Dutch population-based case-control study of 143 children with CHD and 186 healthy children, we investigated S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), total homocysteine (tHcy), the vitamins folate and B12 and the functional single nucleotide polymorphisms in the folate gene MTHFR 677C>T and 1298A>C. Comparisons were made between cases and controls adjusting for age, medication, vitamin use and CHD family history.

RESULTS

In the overall CHD group, the median concentrations of SAM (P = 0·011), folate in serum (P = 0·021) and RBC (P = 0·030) were significantly higher than in the controls. Subgroup analysis showed that this was mainly attributable to complex CHD with higher SAM (P < 0·001), SAH (P = 0·012) and serum folate (P = 0·010) independent of carriership of MTHFR polymorphisms. Highest concentrations of SAM, SAH and folate RBC were observed in complex syndromic CHD. The subgroup of children with Down syndrome, however, showed significantly higher SAH (P = 0·037) and significantly lower SAM:SAH ratio (P = 0·034) compared with other complex CHD, suggesting a state of global hypomethylation.

CONCLUSION

High concentrations of methylation biomarkers in very young children are associated with complex CHD. Down syndrome and CHD may be associated with a global hypomethylation status, which has to be confirmed in tissues and global DNA methylation in future studies.

Relation of body mass index to blood folate and total homocysteine concentrations in Japanese adults

PURPOSE

Plasma folate concentrations are suggested to be negatively associated with body mass index (BMI, kg/m(2)), although these findings are controversial. Our objective was to evaluate the association of BMI with blood folate and total homocysteine (tHcy) concentrations.

METHODS

We measured plasma and erythrocyte folate and plasma tHcy concentrations in 434 healthy adults (343 women and 91 men; mean age of 63.8 ± 10.7 [SD, range 23-88] years), who participated in a 2007 population-based survey in western Japan.

RESULTS

The overall mean plasma and erythrocyte folate and tHcy were 21.6 (±11.0, SD) nmol/L, 844 (±291) nmol/L and 11.6 (±3.9) μmol/L, respectively. The mean BMI was 22.8 (±3.0; 15.6-33.3) kg/m(2), and only 72 subjects (17%) had BMI > 26.0 kg/m(2). Mean plasma folate decreased as BMI increased (p-trend < 0.01), whereas mean erythrocyte folate and plasma tHcy were similar regardless of BMI (p-trends = 0.49 and 0.28, respectively).

CONCLUSION

Our data indicate that the interpretation of plasma folate concentrations to assess folate nutritional status is complicated by BMI, although the impact of BMI on plasma folate was relatively small. It is important to take this association into account for the selection of subjects for future large-scale studies. The mechanism of this inverse association between BMI and plasma folate concentrations should be investigated.

Association of methylenetetrahydrofolate reductase C677T polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

Background

The association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and serum lipid profiles is still controversial in diverse ethnics. Bai Ku Yao is an isolated subgroup of the Yao minority in China. The aim of the present study was to eveluate the association of MTHFR C677T polymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations.

Methods

A total of 780 subjects of Bai Ku Yao and 686 participants of Han Chinese were randomly selected from our previous stratified randomized cluster samples. Genotyping of the MTHFR C677T was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing.

Results

The levels of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein (Apo) AI and ApoB were lower in Bai Ku Yao than in Han (P < 0.05-0.001). The frequency of C and T alleles was 77.4% and 22.6% in Bai Ku Yao, and 60.9% and 39.1% in Han (P < 0.001); respectively. The frequency of CC, CT and TT genotypes was 58.7%, 37.3% and 4.0% in Bai Ku Yao, and 32.6%, 56.4% and 11.0% in Han (P < 0.001); respectively. The levels of TC and LDL-C in both ethnic groups were significant differences among the three genotypes (P < 0.05-0.01). The T allele carriers had higher serum TC and LDL-C levels than the T allele noncarriers. The levels of ApoB in Han were significant differences among the three genotypes (P < 0.05). The T allele carriers had higher serum ApoB levels as compared with the T allele noncarriers. The levels of TC, TG and LDL-C in Bai Ku Yao were correlated with genotypes (P < 0.05-0.001), whereas the levels of LDL-C in Han were associated with genotypes (P < 0.001). Serum lipid parameters were also correlated with sex, age, body mass index, alcohol consumption, cigarette smoking, and blood pressure in the both ethnic groups.

Conclusions

The differences in serum TC, TG, LDL-C and ApoB levels between the two ethnic groups might partly result from different genotypic and allelic frequencies of the MTHFR C677T or different MTHFR gene-enviromental interactions.

Genetic variability in the MTHFR gene and colorectal cancer risk using the colorectal cancer family registry

BACKGROUND

The MTHFR C677T TT genotype is associated with a 15% to 18% reduction in colorectal cancer risk, but it is not clear if other variants of the gene are associated with colorectal cancer risk.

METHODS

We used a tagSNP approach to comprehensively evaluate associations between variation in the MTHFR gene and colorectal cancer risk using a large family-based case-control study of 1,750 population-based and 245 clinic-based families from the Colon Cancer Family Registry. We assessed 22 TagSNPs, selected based on pairwise r(2) >95%, using the Haploview Tagger and genotyped the TagSNPs on the Illumina GoldenGate or Sequenom platforms. The association between single nucleotide polymorphisms and colorectal cancer was assessed using log-additive, codominant, and recessive models.

RESULTS

From studying the population-based families, the C677T (rs1801133) and A1298C (rs1801131) polymorphisms were associated with a decreased colorectal cancer risk overall [odds ratio (OR), 0.81; 95% confidence interval (95% CI), 0.63-1.04; and OR, 0.82; 95% CI, 0.64-1.07, respectively]. The 677 TT genotype was associated with a decreased risk of microsatellite-stable/microsatellite-low tumors (OR, 0.69; 95% CI, 0.49-0.97) and an increased risk of microsatellite-high tumors (OR, 2.22; 95% CI, 0.91-5.43; P(interaction) = 0.01), as well as an increased risk of proximal cancers and a decreased risk of distal and rectal cancers (P(interaction) = 0.02). No other single nucleotide polymorphism was associated with risk overall or within subgroups.

CONCLUSION

The 677 TT and 1298 CC genotypes may each be associated with a decrease in colorectal cancer risk. We observed little evidence of additional genetic variability in the MTHFR gene relevant to colorectal cancer risk.

Serum homocysteine in Indian adolescents

OBJECTIVE

To assess serum homocysteine levels and its association with conventional risk factors for cardiovascular disease (CVD) in Indian adolescents.

METHODS

This was a cross-sectional study conducted in tertiary care hospital in northern India in apparently healthy adolescents aged 10-19 yr. A pre-designed questionnaire was used to assess conventional risk factors. Serum homocysteine levels of > or = 12 micromol/L, serum triglycerides > or = 150 mg% and serum cholesterol > or = 200 mg% were taken as hyperhomocysteinemia, hypertriglyceridemia and hypercholesterolemia, respectively. Serum high-density lipoprotein (HDL) > or = 40 mg% was considered protective for CVD.

RESULTS

In 103 subjects, 36.87 % females, mean serum homocysteine level was 11.649 +/-0.416 micromol/L. Hyperhomocysteinemia was present in 46 (44.6%, 95% CI: 34.965-54.75) subjects. Dietary deficiency of vitamin B12 and folic acid, body mass index (BMI) > 84(th) percentile and altered lipid profile were associated with hyperhomocysteinemia on univariate analysis. After multivariate adjustment for BMI and vegetarian diet, low serum HDL (OR: 23.81, 95% CI: 2.86-200; p = 0.003) and serum hypertriglyceridemia (OR: 4.17, 95% CI: 1.51-13.51; p = 0.022) had independent association with hyperhomocysteinemia.

CONCLUSION

Since we have also found an association between hyperhomocysteinemia and low serum HDL levels and hypertriglyceridemia, which are conventional risk factors for CVD, interventional strategies are urgently needed among adolescents for prevention of CVD.

Total homocysteine, B-vitamins and genetic polymorphisms in patients with classical phenylketonuria

Hyperhomocysteinemia has occasionally been reported in patients with phenylketonuria (PKU) and B-vitamin deficiency. In our study total homocysteine (tHcy) and B-vitamins were measured in treated PKU patients and healthy controls. In the patients, dietary parameters and genetic polymorphisms affecting the Hcy pathway were investigated to identify parameters modulating tHcy. A case control study including 37 PKU patients and 63 healthy controls was conducted. t-Tests for independent samples were used to test between groups. Multiple regressions with tHcy as dependent variable were calculated. Hardy-Weinberg expectations were tested against the observed distribution of genotypes applying the Chi-square goodness-of-fit method. THcy concentrations were not significantly different (p=0.059) while folate and cobalamin (Cbl) concentrations were significantly higher in PKU patients compared to controls. However, 29.7% of patients had tHcy concentrations >97th centile. THcy did not vary with age nor correlate with folate and Cbl concentrations probably due to high saturatory levels. The presence of genetic polymorphisms had no impact on tHcy. In conclusion, in PKU patients treated with amino acid mixtures enriched with B-vitamins, tHcy is not significantly higher than in healthy controls, but tHcy concentrations exceed the 97th centile in about one third of patients. Even higher B-vitamin saturation may be required to further decrease tHcy concentrations and factors generally influencing tHcy such as betaine are to be investigated in PKU patients in the future.

Marginal folate inadequacy observed in a group of young children in Kwangju, Korea

Folate is important for multiple metabolic processes such as nucleic acid synthesis and interconversions, and cell division. Folate deficiency may be a risk factor for several pathologies, such as neural tube birth defects, dementia, and cardiovascular diseases. The objectives of this study were to estimate folate intakes and plasma concentrations of young children living in Kwangju, Korea. Three consecutive 24-h food recalls and fasting blood samples were obtained from 24 boys and 30 girls, aged 2-6 y, living in Kwangju, Korea. The daily folate intake (mean ± SD) of the children was 146.7 ± 73.6 µg dietary folate equivalents. No differences in folate intakes were observed by gender (p≥0.05). The mean folate intakes of the 2 and 3 y old groups were significantly lower (p<0.05) than those of 5 and 6 y old groups. Over half of subjects consumed <Korean Estimated Average Requirements for folate. The plasma folate concentration (mean ± SD) of all subjects was 19.2 ± 8.7 nmol/L, and there was no significant difference by age nor gender (p≥0.05). No significant correlation was observed between folate intakes and plasma folate concentrations. One subject (1.9%) in this study had a plasma folate concentration <6.8 nmol/L, which is indicative of folate deficiency. Approximately 24% of subjects had plasma folate concentrations of 6.8-13.4 nmol/L, which is representative of marginal folate status. In conclusion, some young children may have less than adequate folate status in Korea.