Table 4

Adenoma OR* (95% CI) for joint effects of HAA intakes and smoking by NAT2 and CYP1A2 activities

HAA sourceTertile cutpointNAT2 N OR (95% CI)pinteraction ValueCYP1A2§ N OR (95% CI)pinteraction Value
PhIP (ng/day)<49T153/1011.00.54T157/871.00.71
50–14065/851.47 (0.91 to 2.39)53/940.74 (0.45 to 1.21)
>14076/901.45 (0.90 to 2.33)71/921.01 (0.62 to 1.62)
<49T260/931.16 (0.71 to 1.88)T259/950.80 (0.49 to 1.29)
50–14071/871.50 (0.92 to 2.50)66/900.99 (0.61 to 1.60)
>14078/981.37 (0.85 to 2.20)74/901.06 (0.66 to 1.71)
<49T358/821.51 (0.91 to 2.50)T358/910.87 (0.54 to 1.42)
50–14069/1061.34 (0.82 to 2.18)75/911.13 (0.70 to 1.82)
>14091/892.14 (1.31 to 3.49)89/911.26 (0.78 to 2.02)
DiMeIQx (ng/day)<0.77T162/1041.00.52T150/1031.000.35
0.77–3.2766/781.30 (0.81 to 2.09)70/871.57 (0.98 to 2.54)
>3.2766/941.05 (0.66 to 1.68)61/831.31 (0.80 to 2.16)
<0.77T271/911.22 (0.77 to 1.93)T270/831.62 (1.01 to 2.62)
0.77–3.2775/931.15 (0.72 to 1.84)65/991.15 (0.71 to 1.85)
>3.2763/941.03 (0.64 to 1.66)64/931.28 (0.78 to 2.09)
<0.77T360/821.32 (0.81 to 2.16)T366/881.47 (0.91 to 2.38)
0.77–3.2773/1071.16 (0.72 to 1.87)79/871.64 (1.02 to 2.64)
>3.2785/881.70 (1.06 to 2.75)77/981.47 (0.90 to 2.38)
MeIQx (ng/day)<22.4T153/991.00.15T148/981.00.97
22.4–82.170/901.25 (0.77 to 2.02)66/971.28 (0.79 to 2.07)
>82.171/871.31 (0.80 to 2.14)67/781.46 (0.88 to 2.42)
<22.4T270/931.25 (0.78 to 2.02)T262/881.29 (0.79 to 2.10)
22.4–82.179/891.46 (0.90 to 2.37)64/881.25 (0.77 to 2.05)
>82.160/960.98 (0.59 to 1.61)73/991.32 (0.81 to 2.15)
<22.4T360/841.43 (0.86 to 2.36)T363/871.43 (0.88 to 2.34)
22.4–82.164/1001.17 (0.71 to 1.93)77/891.49 (0.91 to 2.43)
>82.194/931.91 (1.16 to 3.16)82/971.51 (0.92 to 2.46)
HAA (ng/day)<89.1T154/1031.00.51T155/1021.00.99
89.1–23766/891.28 (0.79 to 2.08)59/841.11 (0.68 to 1.81)
>23774/841.48 (0.91 to 2.41)67/871.18 (0.73 to 1.91)
<89.1T268/961.24 (0.77 to 1.99)T257/851.04 (0.64 to 1.69)
89.1–23769/801.51 (0.92 to 2.48)73/961.25 (0.78 to 2.00)
>23772/1021.16 (0.71 to 1.87)69/941.13 (0.70 to 1.82)
<89.1T353/771.40 (0.83 to 2.35)T357/861.11 (0.68 to 1.81)
891–23775/1091.38 (0.85 to 2.24)75/941.27 (0.79 to 2.04)
>23790/911.95 (1.19 to 3.18)90/931.52 (0.95 to 2.44)
Pack-years0T174/1291.00.66T190/1521.00.08
1–1955/701.32 (0.83 to 2.11)46/771.11 (0.70 to 1.77)
>1965/771.48 (0.93 to 2.35)62/601.94 (1.22 to 3.08)
0T287/1560.86 (0.57 to 1.29)T279/1500.87 (0.59 to 1.29)
1–1957/611.65 (1.02 to 2.66)62/801.35 (0.87 to 2.08)
>1965/611.75 (1.08 to 2.83)69/582.23 (1.41 to 3.53)
0T388/1331.23 (0.80 to 1.89)T372/1091.23 (0.81 to 1.85)
1–1955/761.38 (0.86 to 2.24)56/511.96 (1.22 to 3.16)
>1975/682.28 (1.42 to 3.67)66/841.37 (0.88 to 2.13)
  • * OR and 95% CI are estimated by unconditional logistic regression, adjusted for sex, age, race/ethnicity, initial examination modality (flexible sigmoidoscopy or colonoscopy) and clinic, date of screening, family history of colorectal cancer, body mass index 5 years ago, energy-adjusted dietary fibre, energy-adjusted total intakes (foods and supplements) of calcium and folate, pack-years of smoking and alcohol intake.

  • Cutpoints are 0.29 and 0.58 based on all controls.

  • Number of cases/number of controls.

  • § Cutpoints are 0.87 and 1.08 based on all controls.

  • Energy-adjusted by the method of residuals.

  • CYP1A2, cytochrome P450 1A2; Di-MeIQx, 2-amino-3,4,8-dimethylimidazo[4,5-f]quinoxaline; HAA, heterocyclic amine; MeIQx, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline; NAT2, N-acetyltransferase-2; PhIP, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine.