1.
Plasma Homocysteine, Serum Folic Acid, Serum Vitamin B12, Serum Vitamin B6, MTHFR, and Risk of Normal-Tension Glaucoma.
Li, J, Xu, F, Zeng, R, Gong, H, Lan, Y
Journal of glaucoma. 2016;(2):e94-8
Abstract
BACKGROUND This meta-analysis aims to comprehensively evaluate the association between total homocysteine (tHcy) levels, serum folic acid, vitamin B12, vitamin B6 levels, methylenetetrahydrofolate reductase (MTHFR) C677T genotype, and risk of normal-tension glaucoma (NTG). MATERIALS AND METHODS A systematic search of the EMBASE and PubMed databases was performed to evaluate plasma tHcy levels, serum folic acid, B vitamins' mean difference, and odds ratios of MTHFR C677T genotype between cases and controls. RESULTS A total of 7 studies including 458 cases and 555 controls meeting the inclusion criteria were involved in this meta-analysis. There were 4 studies for tHcy (149 cases and 148 controls), 2 studies for vitamin B6, vitamin B12, and folate (90 cases and 82 controls), and 4 studies for MTHFR (343 cases and 449 controls). Overall, the mean plasma tHcy levels, serum folic acids, vitamin B12, and vitamin B6 levels were 1.16 μmol/L [95% confidence interval (CI), -0.13, 2.45], -0.62 μmol/L (95% CI, -1.98, 0.74), 5.81 μmol/L (95% CI, -3.53, 15.14), and -16.79 μmol/L (95% CI, -86.09, 52.51). MTHFR TT genotype was found to be unrelated to NTG risk (odds ratio=1.08; 95% CI, 0.69, 1.69). CONCLUSION NTG is not associated with elevated plasma tHcy, serum folic acid, serum vitamin B12, serum vitamin B6, and MTHFR C677T genotype.
2.
Plasma homocysteine, serum folic acid, serum vitamin B12, serum vitamin B6, MTHFR and risk of pseudoexfoliation glaucoma: a meta-analysis.
Xu, F, Zhang, L, Li, M
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2012;(7):1067-74
Abstract
BACKGROUND The aim of this meta-analysis is to explore the relationship between plasma total homocysteine (tHcy) levels, serum folic acid, vitamin B12 and vitamin B6 levels, methylenetetrahydrofolate reductase (MTHFR) C677T genotype and risk of pseudoexfoliation glaucoma (PEXG). METHODS A systematic search of EMBASE and PubMed of relevant articles was carried out for all published articles. Main outcome measures included the calculation of plasma tHcy levels, serum folic acid, vitamin B12, and vitamin B6 levels mean difference and odds ratios (OR) of MTHFR C677T genotype between cases and controls. RESULTS There were 14 studies for tHcy (485 cases and 456 controls), five studies for folic acid (188 cases and 189 controls), six studies for vitamin B12 (199 cases and 225 controls), three studies for vitamin B6 (128 cases and 130 controls) and eight studies for MTHFR (479 cases and 661 controls). Overall, the mean plasma tHcy levels in cases was 3.38 umol/l (95% confidence intervals (CI): 2.35-4.42) higher than in controls. Serum folic acids, but not vitamin B12 and vitamin B6 levels, was significantly lower in cases than in controls; the weighted mean differences with 95% CI were -1.50 umol/l (-2.53, -0.46), -36.29 umol/l (-81.27, 8.68) and -0.60 umol/l (-2.55, 1.35) respectively. There was no evidence of association between the MTHFR C677T genotype and PEXG (OR = 1.28, 95% CI: 0.85, 1.93). CONCLUSIONS PEXG is associated with elevated plasma tHcy and low serum folic acid levels, but not serum vitamin B12, vitamin B6 levels, and MTHFR C677T genotype.
3.
Homocysteine, B vitamins, methylenetetrahydrofolate reductase gene, and risk of primary open-angle glaucoma: a meta-analysis.
Xu, F, Zhao, X, Zeng, SM, Li, L, Zhong, HB, Li, M
Ophthalmology. 2012;(12):2493-9
Abstract
BACKGROUND To evaluate the association between plasma total homocysteine (tHcy) levels, serum folic acid, vitamin B(12) and vitamin B(6) levels, methylenetetrahydrofolate reductase (MTHFR) C677T genotype and risk of primary open-angle glaucoma (POAG). CLINICAL RELEVANCE There are conflicting reports on the association of Hcy, folic acid, vitamin B(12), vitamin B(6), MTHFR, and risk of POAG. We conducted this meta-analysis to derive a more precise estimation of the association. METHODS Pertinent articles were identified through a systematic search of the EMBASE and Medline databases. Results were pooled using meta-analytic methods. The main outcome measure included tHcy, folic acid, vitamin B(12) and vitamin B(6) levels, and MTHFR C677T genotype. RESULTS Twelve studies were eligible for Hcy, 6 studies for folic acid, 6 studies for vitamin B(12), 3 studies for vitamin B(6), and 10 studies for MTHFR. The combined results showed that plasma tHcy levels in POAG were 2.05 μmol/L (95% confidence interval [CI], 0.63-3.47) higher than in controls. There was no difference between serum folic acid, vitamin B(6), and vitamin B(12) levels in POAG and controls. The weighted mean difference with 95% CI were 0.34 μmol/L (-0.37 to 1.05), 2.75 μmol/L (-3.68 to 9.18), and 0.97 μmol/L (-30.45 to 32.40), respectively. The MTHFR 677TT genotype was not associated with the risk of POAG (odds ratio, 1.10; 95% CI, 0.83-1.47). CONCLUSIONS We found that POAG is associated with elevated plasma tHcy levels, but not serum folic acid, vitamin B(12), vitamin B(6) levels, or MTHFR C677T genotype. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.