Table 3.

Effect of folate treatment on the risk of adenomas, by MTHFR genotype

GenotypeAny adenoma
Advanced adenoma*
NsFolate/Placebo RR (95% CI)NsFolate/Placebo RR (95% CI)
677C>T (n) Folate/PlaceboFolate /PlaceboFolate/Placebo
CC (204/201)96/861.09 (0.87-1.36)21/220.96 (0.54-1.68)
CT (203/197)93/841.06 (0.85-1.33)22/151.48 (0.78-2.79)
TT (43/50)16/200.93 (0.57-1.53)4/41.30 (0.34–4.96)
1298A>C (n)
AA (218/226)91/911.01 (0.81-1.26)22/211.11 (0.62-1.98)
AC (189/190)94/841.11 (0.89-1.39)21/171.22 (0.66-2.27)
CC (44/33)20/161.02 (0.62-1.68)6/31.40 (0.36-5.38)
MTHFR 677/1298 Genotype
CC/AA (69/68)27/280.90 (0.60-1.35)4/100.39 (0.13-1.19)
CC/AC (92/100)49/421.25 (0.92-1.72)13/91.41 (0.62-3.22)
CC/CC (43/33)20/161.04 (0.63-1.72)6/31.44 (0.37-5.54)
CT/AA (106/108)48/431.12 (0.82-1.53)14/72.05 (0.85-4.95)
CT/AC (97/89)45/410.99 (0.72-1.37)8/80.99 (0.38-2.55)
TT/CC (43/50)16/200.93 (0.56-1.53)4/41.30 (0.34-4.95)
  • * Advanced adenoma defined as tubulovillous or villous adenoma, large adenoma (≥1 cm), carcinoma in situ, or invasive cancer.

  • Number of subjects in folate/placebo treatment groups.

  • RR, risk ratio for effect of 1 mg/day folate supplement versus placebo on adenoma recurrence risk; RRs were adjusted for age, sex, clinical center, and aspirin treatment assignment.