vitamin-b-12 and Cataract

Topics: Adrenalectomy; Amblyopia; Aminosalicylic Acids; Anticoagulants; Cataract; Clofibrate; Diabetic Retinopathy; Diet; Diplopia; Fructose; Glaucoma; Humans; Light Coagulation; Lipotropic Agents; Pituitary Gland; Retina; Rutin; Steroids; Vision Disorders; Vitamin B 12

To examine the incidence of cataract and cataract extraction in a trial of folic acid and vitamins B6 and B12.. In a randomized, double-masked, placebo-controlled trial, 5442 female health professionals aged 40 years or older with preexisting cardiovascular disease (CVD) or three or more CVD risk factors were randomly assigned to receive a combination of folic acid (2.5 mg/day), vitamin B6 (50 mg/day), and vitamin B12 (1 mg/day), or placebo. A total of 3925 of these women did not have a diagnosis of cataract at baseline and were included in this analysis. The primary endpoint was age-related cataract, defined as an incident age-related lens opacity, responsible for a reduction in best-corrected visual acuity to 20/30 or worse, based on self-report confirmed by medical record review. Extraction of incident age-related cataract was a secondary endpoint of the trial.. During an average of 7.3 years of treatment and follow-up, 408 cataracts and 275 cataract extractions were documented. There were 215 cataracts in the combination treatment group and 193 in the placebo group (hazard ratio, HR, 1.10, 95% confidence interval, CI, 0.90-1.33; p = 0.36). For the secondary endpoint of cataract extraction, there were 155 in the combination treatment group and 120 in the placebo group (HR 1.28, 95% CI 1.01-1.63; p = 0.04).. In this large-scale randomized trial of women at high risk of CVD, daily supplementation with a combination of folic acid, vitamin B6, and vitamin B12 had no significant effect on cataract, but may have increased the risk of cataract extraction.

Topics: Adult; Aged; Cardiovascular Diseases; Cataract; Cataract Extraction; Double-Blind Method; Drug Combinations; Female; Folic Acid; Health Personnel; Humans; Incidence; Middle Aged; Risk Factors; Vitamin B 12; Vitamin B 6; Vitamin B Complex

Homocysteine (Hcy) is a potential risk factor for age-related cataract (ARC). Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme for Hcy metabolism, and variants of MTHFR may affect MTHFR enzyme activity. This study mainly evaluated the associations between variants in MTHFR gene, plasma MTHFR enzyme activity, total Hcy (tHcy) levels and ARC risk in Chinese population. Four single nucleotide polymorphisms (SNPs) in MTHFR gene were genotyped using the high-resolution melting (HRM) method in 502 ARC patients (mean age, 70.2 [SD, 9.0], 46.0% male) and 890 healthy controls (mean age, 67.1 [SD, 11.1], 47.6% male). The plasma MTHFR activity, folic acid (FA), vitamins B12 and B6 levels were detected by enzyme-linked immunosorbent assays (ELISA). The plasma tHcy levels were measured by an automated enzymatic assay. After the Bonferroni correction, the minor allele T of SNP rs1801133 showed a significant association with an increased risk of overall ARC (OR = 1.26, P = 0.003). Consistent association was also found between SNP rs1801133 and cortical ARC risk (OR = 1.44, P = 0.003). Haplotype analyses revealed an adverse effect of the haplotype "C-A-T-C" (alleles in order of SNPs rs3737967, rs1801131, rs1801133 and rs9651118) on ARC risk (OR = 1.55, P = 0.003). Moreover, in a joint analysis of SNPs rs9651118 and rs1801133, subjects with two unfavorable genotypes had a 1.76-fold increased risk of ARC compared with the reference group, and a statistically significant dose-response trend (Ptrend = 0.001) was also observed. Further, in healthy controls and patients with cortical ARC, the allele T of SNP rs1801133 and the increasing number of unfavorable genotypes were significantly correlated with decreased MTHFR activity as well as increased tHcy levels. However, there was no significant association between FA, vitamins B12, B6 levels and MTHFR variants. Our data indicated that variants in MTHFR gene might individually and jointly influence susceptibility to ARC by affecting MTHFR enzyme activity and tHcy levels.

Topics: Aged; Aged, 80 and over; Aging; Asian People; Case-Control Studies; Cataract; Female; Genetic Predisposition to Disease; Haplotypes; Homocysteine; Humans; Male; Methylenetetrahydrofolate Reductase (NADPH2); Middle Aged; Polymorphism, Single Nucleotide; Vitamin B 12; Vitamin B 6

We assessed associations between serum levels of homocysteine, vitamin B12, and folate, and the prevalence and 5-year incidence of posterior subcapsular cataract (PSC) in Blue Mountains Eye Study participants.. We examined 3508 participants aged 49+ years during 1997 to 2000, including 2334 (75.1% of survivors) original and 1174 (85.2% of those eligible) newly recruited subjects. Five years later (2002-2004), 1952 (76.6% of survivors) original participants were re-examined. Detailed examinations, including lens photographs and fasting blood tests, were conducted at both visits. Logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI) after multivariable adjustment.. In this population, those with PSC were older, less likely to have higher education, and more likely to have diabetes and myopia. The PSC prevalence was 5.7% (150/2644). Higher levels of homocysteine (per SD; OR, 1.17; 95% CI, 1.00-1.37) and lower levels of folate (per SD; OR, 1.24; 95% CI, 0.99-1.56) were associated with prevalent PSC. There was significant interaction (P < 0.05) between vitamin B12 and homocysteine; for B12 ≥125 pmol/L, 28% higher PSC prevalence was associated with homocysteine (per SD; OR, 1.28; 95% CI, 1.09-1.52); however, for B12 <125 pmol/L, nonsignificant lower PSC prevalence was associated with homocysteine (per SD; OR, 0.16; 95% CI, 0.02-1.57). The 5-year PSC incidence was 5.7% (n = 59/1030) with no significant associations with homocysteine, B12, and folate.. Higher serum homocysteine level was associated with PSC prevalence in this population. Vitamin B12 status seemed to modify this association. Lack of longitudinal association could have resulted from insufficient study power.

Topics: Aged; Biomarkers; Cataract; Cross-Sectional Studies; Female; Folic Acid; Follow-Up Studies; Homocysteine; Humans; Incidence; Male; Middle Aged; New South Wales; Population Surveillance; Prevalence; Retrospective Studies; Vitamin B 12

Topics: Arteriosclerosis; Blood Glucose; Blood Proteins; Cataract; Cholesterol; Classification; Diabetes Mellitus; Diabetic Retinopathy; Eye Manifestations; Fibrinolysin; Humans; Japan; Pathology; Retinitis; Statistics as Topic; Vitamin B 12