Table 1.
General participant characteristics by MTHFR genotype
| MTHFR genotypea | ||||
|---|---|---|---|---|
| CC (n = 2677) | CT (n = 2660) | TT (n = 739) | P valueb | |
| MTHFR genotype, n (%) | 2677 (44) | 2660 (44) | 739 (12) | |
| Age, years | 68.9 (15.1) | 69.0 (15.5) | 68.6 (15.6) | 0.806 |
| Sex, male | 943 (35%) | 961 (36%) | 256 (35%) | 0.678 |
| Waist, cm | 94.5 (13.9) | 94.5 (14.1) | 94.7 (14.7) | 0.982 |
| Height, cm | 162.6 (10.2) | 162.9 (10.1) | 162.6 (10.0) | 0.619 |
| Weight, kg | 73.7 (16.5) | 73.7 (16.8) | 74.2 (17.3) | 0.853 |
| Body mass index, kg/m2 | 27.8 (5.2) | 27.7 (5.4) | 27.9 (5.2) | 0.458 |
| Current smokers, n (%) | 359 (13%) | 355 (13%) | 89 (12%) | 0.530 |
| Alcohol Intake, units/week | 8.6 (12.2) | 8.8 (12.7) | 8.0 (11.3) | 0.402 |
| Serum triglycerides, mmol/L | 1.51 (0.84) | 1.56 (0.88) | 1.55 (0.78) | 0.087 |
| Serum total cholesterol, mmol/L | 4.68 (1.03) | 4.68 (1.06) | 4.73 (1.05) | 0.383 |
| Serum HDL, mmol/L | 1.51 (0.49) | 1.48 (0.45) | 1.49 (0.47) | 0.439 |
| Calculated LDL, mmol/L | 2.50 (0.88) | 2.50 (0.89) | 2.54 (0.88) | 0.472 |
| Serum creatinine, μmol/L | 86.3 (27.4) | 86.0 (26.4) | 85.9 (27.2) | 0.928 |
| B-vitamin biomarkers | ||||
| Red blood cell folate, nmol/L | 1095 (579)a | 1088 (626)a | 971 (563)b | < 0.001 |
| Serum vitamin B12, pmol/L | 295 (155) | 295 (238) | 296 (238) | 0.194 |
| Riboflavin status, EGRacc | 1.35 (0.21) | 1.35 (0.21) | 1.34 (0.21) | 0.769 |
| Plasma homocysteine, μmol/L | 14.2 (5.4)a | 14.3 (5.4)a | 15.7 (6.8)b | < 0.001 |
Data are expressed as mean (standard deviation) or n (%).
aCC (wild type), CT (heterozygous), TT (homozygous variant), genotypes for the MTHFR 677C→T polymorphism
bP value from one-way ANOVA comparing genotype groups, following log-transformation of data for normalisation purposes, as appropriate. Different superscript letters (i.e. a, b) within a row indicate significant differences by Bonferroni post hoc test, whilst the same letter (i.e. a, a) indicates no significant differences. Level of significance (P < 0.003) adjusted for Bonferroni correction (n = 16). Categorical variables are assessed using chi-square analysis
cBiomarker status of riboflavin determined by the functional assay, erythrocyte glutathione reductase activation coefficient (EGRac); higher EGRac values indicate lower riboflavin status