Table 3.
Associations between the genotypes involved in one-carbon metabolism and homocysteine concentration by total population and folate concentration tertiles.
| Homocysteine 1 | Total | Folate Concentration | p-Interaction 3 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| First Tertile | Second Tertile | Third Tertile | |||||||
| Mean | SEM | Mean | SEM | Mean | SEM | Mean | SEM | ||
| MTHFR 677C>T | |||||||||
| C:C | 9.3 | 0.2 | 9.7 | 0.4 | 9.6 | 0.4 | 8.9 | 0.3 | 0.208 |
| C:T | 10.3 | 0.4 | 10.5 | 0.8 | 10.0 | 0.4 | 10.5 | 1.0 | |
| T:T | 12.6 | 1.3 | 12.6 | 1.3 | 10.2 | 1.7 | 13.9 | 3.9 | |
| p-value 2 | 0.000 * | 0.006 * | 0.162 | 0.038 * | |||||
| MTHFR 1298A>C | |||||||||
| A:A | 10.5 | 0.4 | 11.0 | 0.6 | 9.5 | 0.4 | 10.9 | 1.0 | 0.327 |
| A:C | 9.7 | 0.2 | 10.3 | 0.5 | 10.0 | 0.5 | 9.0 | 0.3 | |
| C:C | 9.2 | 0.7 | 7.1 | 0.6 | 12.1 | 1.6 | 8.4 | 1.3 | |
| p-value 2 | 0.304 | 0.121 | 0.190 | 0.187 | |||||
| MTR 2756A>G | |||||||||
| A:A | 10.0 | 0.3 | 10.1 | 0.4 | 9.5 | 0.3 | 10.4 | 0.8 | 0.397 |
| A:G | 10.4 | 0.5 | 11.5 | 1.2 | 10.5 | 0.7 | 9.2 | 0.4 | |
| G:G | 9.1 | 0.5 | 9.6 | 0.7 | 8.5 | 1.0 | 9.8 | 1.5 | |
| p-value 2 | 0.439 | 0.583 | 0.859 | 0.374 | |||||
| MTRR 66A>G | |||||||||
| A:A | 10.2 | 0.4 | 10.4 | 0.5 | 10.0 | 0.6 | 10.6 | 1.1 | 0.825 |
| A:G | 10.0 | 0.4 | 10.6 | 0.8 | 9.5 | 0.5 | 9.6 | 0.9 | |
| G:G | 10.1 | 0.4 | 9.8 | 0.9 | 10.1 | 0.6 | 10.4 | 0.7 | |
| p-value 2 | 0.576 | 0.59 | 0.612 | 0.388 | |||||
| RFC1 80G>A | |||||||||
| G:G | 10.7 | 0.5 | 11.7 | 1.2 | 11.0 | 0.8 | 9.2 | 0.5 | 0.214 |
| G:A | 10.1 | 0.4 | 9.6 | 0.4 | 9.7 | 0.4 | 11.2 | 1.2 | |
| A:A | 9.4 | 0.3 | 10.5 | 0.7 | 8.5 | 0.5 | 9.2 | 0.5 | |
| p-value 2 | 0.281 | 0.920 | 0.001 * | 0.396 | |||||
| deletion DHFR | |||||||||
| WT:WT | 10.4 | 0.6 | 10.5 | 1.3 | 9.7 | 0.8 | 10.8 | 1.3 | 0.535 |
| WT:del | 10.1 | 0.3 | 10.2 | 0.4 | 9.8 | 0.4 | 10.1 | 0.8 | |
| del:del | 10.1 | 0.4 | 11.2 | 0.8 | 10.3 | 0.6 | 8.9 | 0.5 | |
| p-value 2 | 0.312 | 0.071 | 0.667 | 0.836 | |||||
1 Hcy concentration data are mean and SEM. Hcy concentration values were Log transformed before analysis. 2 Linear regression model adjusted by race, sex, age, estimated consumption of total folate (mcg of DFE/day), body mass index, serum concentrations of vitamins folate, B6, and B12. 3 p-value of genotypes-folate concentration interaction term at the linear regression model. * p-values were considered significant (p < 0.05).