Table 4.
Exposure prevalence, hazard ratios for CRC incidence by exposure level, and fractions of CRC incidence attributable to exposure to behavioral risk factors by sociodemographic factors
| Effect modifier | Subgroup 1 |
Subgroup 2 |
Subgroup 3 |
P† | |||
|---|---|---|---|---|---|---|---|
| Behavioral risk factor | PR, % | HR (95% CI)* | PR, % | HR (95% CI)* | PR, % | HR (95% CI)* | |
| Age group, y | <65 | 65–74 | ≥75 | ||||
| Smoking status | |||||||
| 1. Never | 53 | 1 | 47 | 1 | 52 | 1 | |
| 2. Former | 29 | 1.33 (1.18 to 1.51) | 44 | 1.19 (1.06 to 1.34) | 44 | 1.14 (0.98 to 1.33) | |
| 3. Current | 18 | 1.29 (1.07 to 1.55) | 9 | 1.23 (0.98 to 1.54) | 4 | 1.44 (0.94 to 2.20) | |
| PAF (2, 3 → 1) | 13.4 (7.3 to 19.0) | 9.9 (3.6 to 15.8) | 7.5 (–0.3 to 14.7) | P1-2 = .42, P1-3 = .22, P2-3 = .62 | |||
| PAF (3 → 1) | 4.8 (1.0 to 8.4) | 1.9 (–0.3 to 4.1) | 1.5 (–0.6 to 3.6) | P1-2 = .20, P1-3 = .14, P2-3 = .80 | |||
| BMI, kg/m2 | |||||||
| 1. <18.5 | 2 | 1.15 (0.63 to 2.10) | 0 | 1.20 (0.77 to 1.88) | 2 | 0.89 (0.53 to 1.49) | |
| 2. 18.5–24.9 | 37 | 1 | 25 | 1 | 29 | 1 | |
| 3. 25.0–29.9 | 34 | 1.11 (0.97 to 1.28) | 39 | 0.99 (0.87 to 1.12) | 42 | 1.21 (1.03 to 1.42) | |
| 4. ≥30 | 27 | 1.33 (1.15 to 1.55) | 35 | 1.24 (1.07 to 1.44) | 27 | 1.11 (0.88 to 1.40) | |
| PAF (3, 4 → 2) | 11.6 (3.7 to 18.8) | 7.3 (–1.6 to 15.5) | 10.8 (0.3 to 20.3) | P1-2 = .47, P1-3 = .91, P2-3 = .60 | |||
| PAF (4 → 3) | 5.4 (1.1 to 9.6) | 8.4 (3.0 to 13.5) | –2.3 (–8.8 to 3.7) | P1-2 = .39, P1-3 = .04, P2-3 = .01 | |||
| Alcohol consumption, drinks/d | |||||||
| 1. ≤2 | 82 | 1 | 81 | 1 | 89 | 1 | |
| 2. >2 | 18 | 1.33 (1.15 to 1.54) | 19 | 1.28 (1.10 to 1.49) | 11 | 1.25 (0.995 to 1.57) | |
| PAF (2 → 1) | 6.1 (2.7 to 9.3) | 5.4 (1.8 to 8.9) | 2.9 (–0.3 to 6.0) | P1-2 = .78, P1-3 = .17, P2-3 = .29 | |||
| Joint behaviors | |||||||
| PAF: ever smoking, BMI ≥25 kg/m2, and >2 alcoholic drinks/d | 27.7 (19.3 to 35.1) | 20.8 (11.3 to 29.4) | 19.8 (8.1 to 30.0) | P1-2 = .26, P1-3 = .25, P2-3 = .88 | |||
| Educational attainment | Low | Intermediate | High | ||||
| Smoking status | |||||||
| 1. Never | 49 | 1 | 46 | 1 | 67 | 1 | |
| 2. Former | 31 | 1.12 (1.01 to 1.25) | 36 | 1.27 (1.10 to 1.47) | 26 | 1.48 (1.23 to 1.77) | |
| 3. Current | 20 | 1.07 (0.90 to 1.28) | 19 | 1.32 (1.00 to 1.73) | 7 | 2.19 (1.58 to 3.03) | |
| PAF (2, 3 → 1) | 5.3 (–0.5 to 10.8) | 13.8 (5.3 to 21.6) | 17.8 (10.7 to 24.3) | P1-2 = .09, P1-3 = .01, P2-3 = .47 | |||
| PAF (3 → 1) | 1.4 (–2.4 to 5.2) | 5.3 (–0.4 to 10.7) | 7.2 (3.2 to 10.9) | P1-2 = .26, P1-3 = .04, P2-3 = .58 | |||
| BMI, kg/m2 | |||||||
| 1. <18.5 | 2 | 1.01 (0.69 to 1.49) | 1 | 1.12 (0.61 to 2.05) | 2 | 1.11 (0.52 to 2.36) | |
| 2. 18.5–24.9 | 34 | 1 | 31 | 1 | 42 | 1 | |
| 3. 25.0–29.9 | 34 | 1.04 (0.93 to 1.16) | 37 | 1.24 (1.06 to 1.45) | 36 | 1.15 (0.95 to 1.40) | |
| 4. ≥30 | 30 | 1.26 (1.11 to 1.42) | 31 | 1.40 (1.16 to 1.69) | 21 | 1.20 (0.93 to 1.55) | |
| PAF (3, 4 → 2) | 8.3 (1.7 to 14.3) | 17.8 (8.0 to 26.5) | 9.1 (–1.6 to 18.7) | P1-2 = .09, P1-3 = .89, P2-3 = .21 | |||
| PAF (4 → 3) | 6.1 (2.1 to 9.9) | 4.1 (–2.1 to 9.9) | 1.0 (–4.9 to 6.5) | P1-2 = .58, P1-3 = .14, P2-3 = .46 | |||
| Alcohol consumption, drinks/d | |||||||
| 1. ≤2 | 83 | 1 | 79 | 1 | 86 | 1 | |
| 2. >2 | 17 | 1.38 (1.20 to 1.58) | 21 | 1.29 (1.08 to 1.54) | 14 | 1.23 (0.99 to 1.52) | |
| PAF (2 → 1) | 6.3 (3.4 to 9.2) | 6.1 (1.5 to 10.5) | 3.6 (–0.5 to 7.4) | P1-2 = .95, P1-3 = .27, P2-3 = .39 | |||
| Joint behaviors | |||||||
| PAF: ever smoking, BMI ≥25 kg/m2, and >2 alcoholic drinks/d | 18.4 (10.5 to 25.6) | 33.3 (22.8 to 42.3) | 27.5 (16.9 to 36.7) | P1-2 = .02, P1-3 = .15, P2-3 = .41 | |||
| Country of birth | Australia | Elsewhere | |||||
| Smoking status | |||||||
| 1. Never | 50 | 1 | 58 | 1 | |||
| 2. Former | 32 | 1.26 (1.15 to 1.38) | 30 | 1.17 (0.999 to 1.37) | |||
| 3. Current | 18 | 1.28 (1.09 to 1.51) | 12 | 1.33 (1.03 to 1.72) | |||
| PAF (2, 3 → 1) | 12.3 (7.4 to 16.6) | 9.0 (1.7 to 15.7) | P1-2 = .45 | ||||
| PAF (3 → 1) | 4.5 (1.3 to 7.7) | 4.0 (0.1 to 7.8) | P1-2 = .83 | ||||
| BMI, kg/m2 | |||||||
| 1. <18.5 | 2 | 1.11 (0.79 to 1.55) | 2 | 0.81 (0.40 to 1.63) | |||
| 2. 18.5–24.9 | 34 | 1 | 38 | 1 | |||
| 3. 25.0–29.9 | 34 | 1.12 (1.02 to 1.24) | 38 | 1.05 (0.89 to 1.24) | |||
| 4. ≥30 | 30 | 1.41 (1.26 to 1.57) | 23 | 1.06 (0.87 to 1.40) | |||
| PAF (3, 4 → 2) | 14.4 (8.9 to 19.6) | 3.2 (–6.8 to 12.3) | P1-2 = .045 | ||||
| PAF (4 → 3) | 7.4 (3.8 to 10.8) | 0.4 (–4.3 to 4.8) | P1-2 = .02 | ||||
| Alcohol consumption, drinks/d | |||||||
| 1. ≤2 | 80 | 1 | 88 | 1 | |||
| 2. >2 | 20 | 1.27 (1.14 to 1.42) | 12 | 1.49 (1.22 to 1.81) | |||
| PAF (2 → 1) | 5.6 (2.8 to 8.3) | 6.0 (2.6 to 9.2) | P1-2 = .87 | ||||
| Joint behaviors | |||||||
| PAF: ever smoking, BMI ≥25 kg/m2, and >2 alcoholic drinks/d | 28.7 (22.6 to 34.4) | 16.8 (5.9 to 26.5) | P1-2 = .047 | ||||
*
Adjusted for age, sex, study, smoking, BMI, and alcohol consumption. Some percentages do not add up to 100 because of rounding. BMI = body mass index; CI = confidence interval; CRC = colorectal cancer; HR = hazard ratio; PAF = population attributable fraction; PR = prevalence.
†
P value for difference in PAF estimates between subgroups.