The relationships between plasma total homocysteine and selected atherosclerotic risk factors according to the C677T methylenetetrahydrofolate reductase gene in Japanese:

Folate, Vitamin B6 and Vitamin B12 Intake in Relation to Hyperuricemia

To assess the association between intake of folate, vitamin B6, and vitamin B12 with hyperuricemia (HU) among adults from the United States (US), we extracted relevant data from 24,975 US adults aged 20–85 years from the National Health and Nutrition Examination Survey (NHANES) in 2001–2014. All dietary intake was evaluated by 24-h dietary recalls. Multivariable logistic regression analysis was performed to explore the associations after adjustment for confounders. Compared to the lowest quintile (Q1), for males, adjusted odds ratios (ORs) of HU in Q2 to Q5 of folate (dietary folate equivalent, DFE) intake were 0.84 (95% CI, 0.73–0.96), 0.84 (0.73–0.97), 0.72 (0.62–0.84), and 0.64 (0.53–0.77), respectively (p for trend <0.0001). In females, adjusted ORs in Q2 to Q4 of folate (DFE) intake were 0.84 (95% CI, 0.71–0.99), 0.81 (0.68–0.96), and 0.82 (0.68–0.99), with a p for trend of 0.1475. Our findings indicated the intakes of total folate, folic acid, food folate, folate (DFE), vitamin B12, but not vitamin B6, were inversely related to the risk of HU in males. A lower risk of HU with higher intakes of total folate, food folate, and folate (DFE) was found in females, but with no association between intakes of folic acid, vitamin B6, B12, and the risk of HU for females.

Determinants of hyperhomocysteinemia in healthy and hypertensive subjects: A population-based study and systematic review

AIMS

Hyperhomocysteinemia (HHcy) is known to increase the risk of many diseases. Factors influencing HHcy in healthy and hypertensive subjects remain under-researched.

METHODS

A large population-based study was conducted in 60 communities from Shenzhen, China. Responses to standardized questions on lifestyle factors and blood samples were collected from all participants after a 12-h overnight fast. Multiple linear and multivariate logistic regressions were used to explore risk factors for HHcy. Results were then compared to those from a systematic review of English-language articles listed in Pubmed, EBSCOhost, Web of Science, Embase and Cochrane libraries that investigated HHcy risk factors in healthy and hypertensive subjects.

RESULTS

A total of 1586 healthy (Male/Female = 642/944) and 5935 hypertensive subjects (Male/Female = 2928/3007) participated in our population-based study. In logistic regression analyses, age, BMI and creatinine (Cr) were risk factors, while being female, fruit intake and physical activity were protective factors for HHcy in healthy subjects. In hypertensive subjects, seven [age, smoking, salt intake, systolic blood pressure (SBP), uric acid, triglycerides (TG), and Cr] and four [female, fruit intake, total cholesterol (TC), and glucose] factors were associated with higher and lower HHcy respectively. The review of 71 studies revealed that potential risk factors for Hcy included nutritional, physiologic, lifestyle habits, ethnicity, genetics, interactions between gene-environment, gene-gene, gene-nutritional, environment-environment, nutritional-nutritional.

CONCLUSION

Our study indicates the potential importance of increasing folic acid and vitamin B supplementation, daily fruit and vegetable intake, regular exercise and refraining from tobacco smoking and alcohol consumption as preventive strategies for Hcy.

Effects of combined enalapril and folic acid therapy on the serum uric acid levels in hypertensive patients: a multicenter, randomized, double-blind, parallel-controlled clinical trial

Objective The efficacy of combined treatment consisting of enalapril and folic acid (FA) was compared to that of enalapril alone in reducing the serum uric acid (UA) levels in adult hypertensive patients in China. Methods Patients with mild to moderate hypertension (n=480) were randomly assigned to one of three treatment groups: (1) 10 mg enalapril (control group), (2) 10 mg enalapril plus 0.4 mg FA (low-FA group) or (3) 10 mg enalapril plus 0.8 mg FA (high-FA group) daily for eight weeks. The primary outcome was the UA ratio (week 8 UA: baseline UA). Results The final analysis included 450 patients (43.1% men, 27-75 years of age). An adjusted multivariable regression analysis revealed no significant differences in the UA ratio between the three groups after eight weeks of treatment. In the subgroup analysis stratified according to the baseline UA level, the high-FA group demonstrated a significantly greater UA-lowering response among the patients with an elevated baseline UA concentration (UA ≥310 μmol/L) [median UA ratio (25th percentile, 75th percentile): 0.94 (0.83, 1.01)], compared with that observed in the control group [0.97 (0.90, 1.00), p=0.025]. Similar results were found in the participants with baseline hyperuricemia (HUA; UA: men >420 μmol/L, women >350 μmol/L). Conclusion In this sample of adult hypertensive patients, the administration of a daily dose of 10 mg of enalapril combined with 0.8 mg of FA had a greater beneficial effect on the serum UA levels than did that of 10 mg of enalapril alone in patients with either an elevated UA concentration or HUA.

Pharmacogenetic study of methylenetetrahydrofolate reductase and thymidylate synthase in Japanese and assessment of ethnic and gender differences

OBJECTIVES

We investigated the four polymorphisms of the 5,10-methylenetetrahydrofolate reductase (MTHFR) and thymidylate synthase (TYMS) genes that are related to the pharmacologically active sites of methotrexate for the treatment of rheumatoid arthritis in 102 healthy Japanese adults and assessed the possibility of ethnic and gender differences.

METHODS

Polymorphisms of MTHFR C677T, A1298C, the two or three 28-bp tandem repeats in the TYMS 5'-untranslated regions (UTR), and the 6-bp deletion/insertion in the TYMS 3'-UTR were measured using polymerase chain reaction with restriction fragment length polymorphism method. Published data on allelic frequencies by ethnic group and gender were collected from Medline.

RESULTS

Allelic frequencies in healthy Japanese adults were: MTHFR 677T allele 41%, MTHFR 1298C allele 22%, TYMS 5'-UTR 3R allele 84%, and TYMS 3'-UTR-6-bp allele 59%. Significant differences were found in the distribution of MTHFR C677T between black and Japanese populations, of TYMS 5'-UTR alleles between Caucasian or black and Japanese populations, and of TYMS 3'-UTR alleles between Caucasian and Japanese populations (p < 0.001). Moreover, a gender difference was found in TYMS 3'-UTR allelic frequency in Japanese (p = 0.015).

CONCLUSION

Ethnic and gender variations in the distribution of these allelic frequencies may associate with the difference in the effects of methotrexate in rheumatoid arthritis patients.

Association of methylenetetrahydrofolate reductase (C677T) polymorphism with hyperuricemia

BACKGROUND AND AIMS

Homozygosity for the thermolabile variant of 5,10-methylene tetrahydrofolate reductase (C677T) has been suggested to be positively associated with the risk of vascular disease and neural tube defects. In addition, recent studies have suggested that elevated serum uric acid predicts ischemic heart disease, and epidemiological data on ethnic groups have suggested that genetic factors are determinants of serum uric acid levels. In this study, we tested the hypothesis that 5,10-methylenetetrahydrofolate reductase (C677T) polymorphism may be associated with hyperuricemia.

METHODS AND RESULTS

Samples from 518 healthy individuals (268 men and 250 women) were analyzed for MTHFR genotyping and serum uric acid. The participants were categorized to homozygous wild type (CC), heterozygous for wild type and thermolabile (CT), or homozygous for the thermolabile (TT) variant. Serum uric acid was significantly higher in males and females with TT genotype than those with either CC or CT genotype (p=0.0001, ANOVA). Univariate and multivariate analysis showed that 5,10-methylenetetrahydrofolate reductase (C677T) polymorphism was a strong correlate and predictor of uric acid in males (r=0.28, p=0.0001, beta=0.673, p=<0.001) and in females (r=0.27, p=0.0001, beta=0.599, p=<0.001). Odds ratio analysis has also shown that the risk of hyperuricemia was greater in males (OR 3.1, CI 1.8-5.2, p=0.001) and females (OR 3.3, CI 1.9-5.7, p=<0.001) with CT genotypes and in males (OR 3.7, CI 1.3-10.7, p=0.014) and females (OR 3.2, CI 1.1-9.7, p=0.032) with TT genotypes than in those with CC genotypes.

CONCLUSION

Results from this study suggest that mutation of 5-MTHFR C677T contributes to the higher uric acid levels in both males and females and may be a risk factor for hyperuricemia.