Table 2

Genotype frequencies, adjusted RRs, and 95% CIs for esophageal, gastric cardia, and combined esophageal and gastric cardia cancers and MTHFR C677T, MTHFR A1298C, and MTRR A66G, Linxian Nutrition Intervention Trials and follow-up 1991 through 1996

GenotypeControl subjects (n = 398)Esophagus cases (n = 129)RRa (95% CI)Gastric cardia cases (n = 90)RRa (95% CI)Esophageal gastric cardia cases (n = 219)RRa (95% CI)
n (%)n (%)n (%)n (%)
MTHFR 677 b
CC65 (16.3)23 (17.8)1.00 (reference)17 (18.9)1.00 (reference)40 (18.3)1.00 (reference)
CT209 (52.5)58 (45.0)0.86 (0.48–1.54)36 (40.0)0.67 (0.35–1.29)94 (42.9)0.78 (0.49–1.26)
TT124 (31.2)48 (37.2)1.24 (0.68–2.26)37 (41.1)1.17 (0.61–2.25)85 (38.8)1.21 (0.74–1.98)
P-trend = 0.32cP-trend = 0.30cP-trend = 0.19c
MTHFR 677
CC or CT274 (68.8)81 (62.8)1.00 (reference)53 (58.9)1.00 (reference)134 (61.2)1.00 (reference)
TT124 (31.2)48 (37.2)1.38 (0.89–2.11)37 (41.1)1.57 (0.98–2.50)85 (38.8)1.45 (1.02–2.05)
MTHFR 1298 d
AA294 (73.9)94 (72.9)1.00 (reference)69 (76.7)1.00 (reference)163 (74.3)1.00 (reference)
AC104 (26.1)32 (24.8)0.92 (0.57–1.48)21 (23.3)0.78 (0.45–1.34)53 (24.2)0.87 (0.59–1.28)
CC03 (2.3)Infinity003 (1.4)Infinity
P = 0.03eP = 0.05e
AC or CC104 (26.1)35 (27.1)1.07 (0.76–1.51)21 (21.8)0.78 (0.45–1.34)56 (25.6)0.91 (0.62–1.34)
MTRR 66 f
AA186 (46.7)50 (38.8)1.00 (reference)43 (47.8)1.00 (reference)93 (42.5)1.00 (reference)
AG179 (45.0)63 (48.8)1.52 (0.97–2.37)37 (41.1)1.04 (0.64–1.69)100 (45.7)1.30 (0.91–1.85)
GG33 (8.3)16 (12.4)1.94 (0.98–3.85)10 (11.1)1.22 (0.56–2.65)26 (11.9)1.59 (0.90–2.79)
P-trend = 0.02cP-trend = 0.66cP-trend = 0.06c
AG or GG212 (53.3)79 (61.2)1.59 (1.04–2.42)96 (53.6)1.07 (0.67–1.70)126 (57.6)1.35 (0.96–1.89)
  • a Adjusted for age, sex, trial, BMI, smoking, and alcohol use during past 12 months.

  • b χ2 test P for MTHFR C677T: esophageal cancer, P = 0.32; gastric cardia cancer, P = 0.09; and combined esophageal/gastric cardia cancer, P = 0.12.

  • c Trends across three genotypes estimated using score tests from a continuous variable based on the number of variant alleles in each genotype.

  • d χ2 test P for MTHFR A1298C and gastric cardia cancer, P = 0.58.

  • e Fisher’s exact test P.

  • f χ2 test P for MTRR A66G: esophageal cancer, P = 0.18; gastric cardia cancer, P = 0.63; combined esophageal/gastric cardia cancer, P = 0.20.