1.
Homocysteine, vitamin B12, and folate levels in patients with multiple sclerosis in Chinese population: A case-control study and meta-analysis.
Pan, L, Yin, Y, Chen, J, Ma, Z, Chen, Y, Deng, X, Zhang, HT, Leng, H, Wu, K
Multiple sclerosis and related disorders. 2019;:101395
Abstract
BACKGROUND Current studies suggested discrepancies on the correlations between multiple sclerosis (MS) and blood levels of homocysteine (Hcy), vitamin B12 (VB12), and folate. We performed a case-control study and meta-analysis to help resolve the controversy of these lab values in Chinese patients with MS. METHODS We recruited 80 Chinese MS patients, 86 age/sex matched neurological controls (patients with peripheral vertigo or sleep disorders), and 80 age- and sex-matched healthy controls. Serum Hcy levels were measured using flourimetric high-performance liquid chromatography, serum levels of VB12 and folate using immune assay. A literature search of PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure, Wanfang, and SinoMed was conducted for case-control studies with pure Chinese populations published up to March 16, 2019. The effective size was estimated by the pooled standardized mean difference (SMD) and associated 95% confidence interval (CI). RESULTS The case-control study results suggest higher Hcy levels (mean ± SD) and frequency of hyperhomocysteinemia in the Chinese MS cases than control groups (all p < 0.001), lower for VB12 levels (mean ± SD, p = 0.043 or 0.039). No significant difference was observed for levels of folate (mean ± SD, both p > 0.05), and for frequency of folate or VB12 deficiency (all p > 0.05). Analysis of pooled SMDs and 95% CIs suggested increased Hcy levels in Chinese MS patients (SMD: 2.31, 95% CI: 1.33-3.28, p < 0.001), and in relapsing or remitting cases relative to controls (SMD: 0.94 or 0.85, 95% CI: 0.49-1.39 or 0.35-1.34, both p < 0.001). The meta-analysis results also suggested reduced VB12 levels in Chinese MS patients (SMD: -0.30, 95% CI: -0.46-0.14, p < 0.001), and in relapsing MS patients compared to controls (SMD: -0.31, 95% CI: -0.47-0.15, p < 0.001), while no statistical difference for cases in remission. No significant difference was observed for levels folate in all comparisons. CONCLUSION Patients with MS tend to have increased blood Hcy levels compared to controls. MS patients of Chinese origin and those in relapse may have decreased levels of VB12. Hcy and VB12 may contribute to pathogenesis of the disease, and VB12 may correlate with MS relapse.
2.
Influence of a methionine synthase (D919G) polymorphism on plasma homocysteine and folate levels and relation to risk of myocardial infarction.
Chen, J, Stampfer, MJ, Ma, J, Selhub, J, Malinow, MR, Hennekens, CH, Hunter, DJ
Atherosclerosis. 2001;(3):667-72
Abstract
Methionine synthase (MS) encodes an enzyme that catalyzes the remethylation of homocysteine to methionine using a methyl group donated by 5-methyltetrahydrofolate, which is the major circulating form of folate in the body. Functional genetic variants of the MS may alter total homocysteine (tHcy) as well as folate levels which are independent risk factors for vascular disease. The influence of a common genetic polymorphism (2756A-->G, D919G) of the MS gene on plasma tHcy and folate levels and its relation to the risk of myocardial infarction (MI) in a prospective study of male physicians in the US was investigated. A nested case-control study was conducted within the Physicians' Health Study which was originally designed as a double-blind trial of aspirin and beta-carotene among 22071 US male physicians, aged 40-84 years in 1982. Sixty-eight percent of participants also donated a blood sample. The study included 387 incident MI case and 767 controls matched on age, smoking status, and time from randomization in 6-month intervals. Individuals with GG genotype had a non-significant reduction of MI risk (RR 0.51, 95% CI 0.17-1.16) compared to individuals with DD genotype after adjusting for MI risk factors. The MS polymorphism was associated with decreased tHcy (10.55, 9.87 and 9.57 nmol/ml for DD, DG and GG genotypes, respectively) and increased folate levels (3.95, 3.78, 7.31 ng/ml for DD, DG and GG genotypes, respectively) only among controls but not cases. It was concluded that influence of the MS (D919G) polymorphism on the plasma tHcy and folate levels is at most moderate, but should be further investigated in other large prospective studies.