Table 4.

Association between average ER/SFRP methylation (z-score) and selected demographic, lifestyle, and dietary variables in the right colon and rectum

CountsOverallRectumRight colon
NT/NL/NRMeana (SE)PbMeana (SE)PbMeana (SE)PbPc
Age, y
 Q1 (30–52)107/107/106−0.40 (0.05)0.0001−0.21 (0.06)0.0001−0.59 (0.05)0.00010.30
 Q2 (53–58)96/94/96−0.17 (0.06)−0.01 (0.08)−0.34 (0.07)
 Q3 (59–64)93/92/92− 0.15 (0.06)0.40 (0.09)−0.11 (0.07)
 Q4 (65–78)92/92/91− 0.50 (0.08)0.76 (0.10)− 0.23 (0.09)
Sex
 Male246/244/244− 0.01 (0.04)0.820.24 (0.06)0.53−0.22 (0.05)0.770.42
 Female142/141/142−0.01 (0.05)0.19 (0.06)−0.20 (0.06)
Race
 White325/322/324− 0.02 (0.03)0.0010.25 (0.05)0.002−0.20 (0.04)0.0090.002
 African American22/22/21−0.36 (0.09)−0.22 (0.10)−0.51 (0.11)
 Hispanic22/22/22−0.01 (0.13)0.05 (0.18)−0.08 (0.13)
 Other19/19/19− 0.00 (0.12)0.45 (0.15)−0.45 (0.13)
Smoking
 Never164/164/163−0.04 (0.04)0.680.21 (0.06)0.36−0.28 (0.06)0.700.49
 Former163/162/163− 0.06 (0.05)0.27 (0.07)−0.14 (0.06)
 Current60/58/58−0.07 (0.07)0.10 (0.10)−0.24 (0.08)
Alcohol
 Never123/123/122− 0.09 (0.07)0.100.34 (0.09)0.12−0.15 (0.07)0.300.65
 1 per day85/83/85−0.04 (0.04)0.16 (0.05)−0.24 (0.05)
 2+ per day165/164/163−0.06 (0.06)0.15 (0.08)−0.26 (0.07)
Treatment
 Placebo190/187/189− 0.03 (0.05)0.340.29 (0.06)0.12−0.22 (0.05)0.960.14
 Folic acid198/198/196−0.03 (0.04)0.16 (0.05)−0.21 (0.05)
Treatment
 Placebo128/126/127−0.04 (0.04)0.780.13 (0.06)0.23−0.19 (0.06)0.420.19
 Aspirin 81 mg137/137/136− 0.05 (0.06)0.30 (0.07)−0.20 (0.06)
 Aspirin 325 mg123/122/122−0.01 (0.05)0.24 (0.07)−0.26 (0.06)
Multivitamin used
 No256/255/253− 0.05 (0.05)0.040.29 (0.06)0.03−0.19 (0.05)0.310.26
 Yes130/130/130−0.06 (0.04)0.13 (0.05)−0.25 (0.05)
Dietary folate, μg/d
 Q1 (78.08–205.86)94/94/93−0.03 (0.05)0.490.18 (0.07)0.32−0.25 (0.06)0.800.64
 Q2 (206.87–277.3)94/94/94− 0.03 (0.07)0.24 (0.09)−0.16 (0.08)
 Q3 (277.31–373.65)94/94/93−0.05 (0.06)0.14 (0.09)−0.25 (0.07)
 Q4 (376.17–1,285.59)93/91/92− 0.06 (0.07)0.33 (0.09)−0.20 (0.07)
Dietary protein, g/d
 Q1 (17.00–44.91)94/94/93− 0.01 (0.06)0.020.21 (0.08)0.08−0.18 (0.07)0.050.42
 Q2 (45.15–60.32)94/93/94− 0.14 (0.07)0.37 (0.10)−0.08 (0.07)
 Q3 (60.70–78.71)94/94/93− 0.00 (0.05)0.28 (0.07)−0.27 (0.07)
 Q4 (78.82–144.62)93/92/92−0.15 (0.06)0.04 (0.07)−0.33 (0.07)

Abbreviations: NT, total individuals; NL, total individuals with samples in the rectum; NR, total individuals with samples on the right side.

  • aMeans are adjusted for age, sex, randomized folate treatment assignment, smoking status, alcohol intake, and adenoma occurrence during the 3-year randomized period.

  • bP value for trend.

  • cP for interaction between colorectal location and variables in the table.

  • dMultivitamins used during the trial did not contain folic acid.