Table 2.
Overall, sex- and age-specific risk of colon and rectal cancer according to SHMT1 C1420T and MTHFR C677T polymorphisms
| Colon cancer | p | Rectal cancer | p | |
|---|---|---|---|---|
| OR* (95% CI) | p† | OR* (95% CI) | p† | |
| SHMT11420 | ||||
| CC | 1.00 (reference) | 0.611 | 1.00 (reference) | 0.014 |
| CT | 1.07 (0.81-1.41) | 0.62 | 0.86 (0.66-1.13) | 0.27 |
| TT | 0.86 (0.56-1.33) | 0.49 | 0.57 (0.36-0.89) | 0.013 |
| CT+TT | 1.02 (0.79-1.32) | 0.90 | 0.80 (0.62-1.03) | 0.08 |
| MTHFR 677 | ||||
| CC | 1.00 (reference) | 0.338 | 1.00 (reference) | 0.083 |
| CT | 1.08 (0.81-1.42) | 0.61 | 1.40 (1.06-1.84) | 0.016 |
| TT | 1.19 (0.80-1.78) | 0.39 | 1.14 (0.75-1.73) | 0.53 |
| CT+TT | 1.11 (0.87-1.44) | 0.43 | 1.35 (1.04-1.74) | 0.024 |
| Males | ||||
| SHMT11420 | ||||
| CC | 1.00 (reference) | 0.334 | 1.00 (reference) | 0.015 |
| CT | 0.93 (0.63-1.39) | 0.73 | 0.92 (0.65-1.29) | 0.63 |
| TT | 0.75 (0.40-1.39) | 0.36 | 0.42 (0.23-0.75) | 0.003 |
| CT+TT | 0.89 (0.61-1.30) | 0.54 | 0.80 (0.58-1.10) | 0.16 |
| MTHFR 677 | ||||
| CC | 1.00 (reference) | 0.121 | 1.00 (reference) | 0.494 |
| CT | 1.36 (0.91-2.05) | 0.14 | 1.45 (1.03-2.05) | 0.034 |
| TT | 1.42 (0.80-2.50) | 0.23 | 0.89 (0.52-1.51) | 0.67 |
| CT+TT | 1.37 (0.94-2.00) | 0.10 | 1.29 (0.94-1.79) | 0.12 |
| Females | ||||
| SHMT11420 | ||||
| CC | 1.00 (reference) | 0.824 | 1.00 (reference) | 0.390 |
| CT | 1.22 (0.83-1.80) | 0.31 | 0.77 (0.49-1.22) | 0.27 |
| TT | 0.94 (0.50-1.74) | 0.83 | 0.97 (0.47-2.01) | 0.93 |
| CT+TT | 1.13 (0.79-1.62) | 0.50 | 0.80 (0.52-1.22) | 0.29 |
| MTHFR 677 | ||||
| CC | 1.00 (reference) | 0.863 | 1.00 (reference) | 0.052 |
| CT | 0.87 (0.59-1.28) | 0.48 | 1.39 (0.88-2.19) | 0.16 |
| TT | 1.07 (0.60-1.90) | 0.82 | 1.81 (0.91-3.60) | 0.09 |
| CT+TT | 0.93 (0.65-1.33) | 0.68 | 1.45 (0.94-2.23) | 0.09 |
| Age < 60 years | ||||
| SHMT11420 | ||||
| CC | 1.00 (reference) | 0.485 | 1.00 (reference) | 0.002 |
| CT | 1.22 (0.82-1.82) | 0.33 | 0.81 (0.55-1.19) | 0.29 |
| TT | 0.67 (0.37-1.23) | 0.19 | 0.32 (0.16-0.61) | 0.0006 |
| CT+TT | 1.08 (0.74-1.57) | 0.69 | 0.69 (0.48-0.99) | 0.044 |
| MTHFR 677 | ||||
| CC | 1.00 (reference) | 0.047 | 1.00 (reference) | 0.112 |
| CT | 1.72 (1.15-2.59) | 0.008 | 1.97 (1.33-2.92) | 0.0007 |
| TT | 1.37 (0.77-2.44) | 0.29 | 0.98 (0.54-1.76) | 0.94 |
| CT+TT | 1.65 (1.14-2.39) | 0.008 | 1.67 (1.16-2.40) | 0.005 |
| Age ≥ 60 years | ||||
| SHMT11420 | ||||
| CC | 1.00 (reference) | 0.943 | 1.00 (reference) | 0.763 |
| CT | 0.91 (0.62-1.34) | 0.64 | 0.90 (0.61-1.32) | 0.58 |
| TT | 1.13 (0.59-2.18) | 0.71 | 1.04 (0.54-1.98) | 0.91 |
| CT+TT | 0.92 (0.64-1.33) | 0.67 | 0.92 (0.64-1.31) | 0.63 |
| MTHFR 677 | ||||
| CC | 1.00 (reference) | 0.489 | 1.00 (reference) | 0.432 |
| CT | 0.70 (0.47-1.03) | 0.07 | 1.03 (0.70-1.52) | 0.89 |
| TT | 0.99 (0.56-1.73) | 0.96 | 1.33 (0.73-2.42) | 0.35 |
| CT+TT | 0.75 (0.52-1.08) | 0.13 | 1.08 (0.74-1.56) | 0.70 |
* adjusted for BMI, sex and age for overall risk, BMI and age for sex-specific risk, BMI and sex for age-specific risk; † test of gene-dosage effect