Table 4.
Associations between baseline serum insulin level and risk of prostate cancer, adjusted for age and body mass index and stratified by selected baseline characteristics: Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study*
| Insulin quartile |
||||||
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | |||
| Subgroup | 1 (≤ 2.75 μU/mL) | 2 (> 2.75 to ≤ 4.10 μU/mL) | 3 (> 4.10 to ≤ 6.10 μU/mL) | 4 (> 6.10 μU/mL) | Ptrend† | Pinteraction† |
| Age, y | ||||||
| <56‡ | 4/51 | 8/50 | 8/55 | 10/42 | ||
| OR (95% CI) | 1.00 (ref) | 1.80 (0.48 to 6.83) | 2.05 (0.52 to 8.02) | 3.36 (0.74 to 15.37) | .13 | |
| ≥56‡ | 13/49 | 15/51 | 19/48 | 23/54 | .56 | |
| OR (95% CI) | 1.00 (ref) | 1.23 (0.53 to 2.90) | 1.79 (0.75 to 4.24) | 2.28 (0.91 to 5.70) | .07 | |
| BMI, kg/m2 | ||||||
| <26.1‡ | 13/78 | 20/69 | 13/36 | 9/15 | ||
| OR (95% CI) | 1.00 (ref) | 2.05 (0.91 to 4.57) | 2.46 (0.98 to 6.18) | 3.89 (1.31 to 11.54) | .01 | |
| ≥26.1‡ | 4/22 | 3/32 | 14/67 | 24/81 | .06 | |
| OR (95% CI) | 1.00 (ref) | 0.53 (0.11 to 2.63) | 1.02 (0.30 to 3.50) | 1.27 (0.37 to 4.36) | .33 | |
| Occupational activity | ||||||
| Low‡ | 10/65 | 18/64 | 24/80 | 32/75 | ||
| OR (95% CI) | 1.00 (ref) | 2.12 (0.89 to 5.04) | 2.31 (0.98 to 5.44) | 3.66 (1.48 to 9.04) | .04 | |
| High‡ | 7/35 | 5/37 | 3/23 | 1/21 | .04 | |
| OR (95% CI) | 1.00 (ref) | 0.71 (0.20 to 2.53) | 0.80 (0.17 to 3.71) | 0.35 (0.03 to 4.00) | .42 | |
| No. of cigarettes per day | ||||||
| <20‡ | 11/30 | 5/34 | 8/35 | 10/29 | ||
| OR (95% CI) | 1.00 (ref) | 0.47 (0.14 to 1.57) | 1.02 (0.33 to 3.17) | 1.64 (0.53 to 5.08) | .21 | |
| ≥20‡ | 6/70 | 18/67 | 19/68 | 23/67 | .94 | |
| OR (95% CI) | 1.00 (ref) | 3.21 (1.18 to 8.78) | 3.16 (1.13 to 8.81) | 3.79 (1.23 to 11.74) | .08 | |
| Total energy, kcal/d | ||||||
| <2721‡ | 6/51 | 10/51 | 12/46 | 16/44 | ||
| OR (95% CI) | 1.00 (ref) | 1.96 (0.64 to 6.00) | 2.61 (0.85 to 8.06) | 4.09 (0.24 to 13.45) | .02 | |
| ≥2721‡ | 10/43 | 12/46 | 14/53 | 13/49 | .63 | |
| OR (95% CI) | 1.00 (ref) | 1.24 (0.48 to 3.24) | 1.29 (0.49 to 3.41) | 1.44 (0.47 to 4.41) | .56 | |
| Dietary protein, g/d | ||||||
| <100‡ | 8/53 | 8/54 | 12/44 | 12/41 | ||
| OR (95% CI) | 1.00 (ref) | 1.14 (0.39 to 3.36) | 2.43 (0.84 to 6.98) | 3.21 (0.99 to 10.42) | .04 | |
| ≥100‡ | 8/41 | 14/43 | 14/55 | 17/52 | .69 | |
| OR (95% CI) | 1.00 (ref) | 1.82 (0.68 to 4.90) | 1.30 (0.47 to 3.62) | 1.75 (0.58 to 5.27) | .48 | |
| Dietary carbohydrate, g/d | ||||||
| <294‡ | 5/48 | 10/53 | 12/51 | 17/39 | ||
| OR (95% CI) | 1.00 (ref) | 2.41 (0.73 to 7.96) | 2.86 (0.85 to 9.59) | 6.20 (1.72 to 22.35) | .005 | |
| ≥294‡ | 11/46 | 12/44 | 14/48 | 12/54 | .21 | |
| OR (95% CI) | 1.00 (ref) | 1.21 (0.48 to 3.06) | 1.37 (0.53 to 3.53) | 1.19 (0.40 to 3.57) | .81 | |
| Alcohol intake, g/d | ||||||
| <11.4‡ | 11/45 | 11/48 | 15/49 | 12/49 | ||
| OR (95% CI) | 1.00 (ref) | 1.02 (0.39 to 2.63) | 1.46 (0.57 to 3.71) | 1.15 (0.39 to 3.38) | .89 | |
| ≥11.4‡ | 5/49 | 11/49 | 11/50 | 17/44 | .15 | |
| OR (95% CI) | 1.00 (ref) | 2.66 (0.83 to 8.55) | 2.42 (0.73 to 8.11) | 5.70 (1.60 to 20.28) | .01 | |
| Time to diagnosis, y | ||||||
| <9.2‡ | 11/100 | 9/101 | 13/103 | 17/96 | ||
| OR (95% CI) | 1.00 (ref) | 0.96 (0.37 to 2.45) | 1.57 (0.63 to 3.88) | 2.84 (1.08 to 7.46) | .02 | |
| ≥9.2‡ | 6/100 | 14/101 | 14/103 | 16/96 | .45 | |
| OR (95% CI) | 1.00 (ref) | 2.47 (0.90 to 6.78) | 2.17 (0.76 to 6.19) | 2.39 (0.76 to 7.55) | .32 | |
| Stage | ||||||
| 0–II‡ | 10/100 | 14/101 | 21/103 | 24/96 | ||
| OR (95% CI) | 1.00 (ref) | 1.62 (0.68 to 3.90) | 2.36 (1.00 to 5.56) | 3.19 (1.25 to 8.13) | .02 | |
| III–IV‡ | 7/100 | 9/101 | 6/103 | 8/96 | 0.38 | |
| OR (95% CI) | 1.00 (ref) | 1.38 (0.49 to 3.91) | 0.98 (0.30 to 3.21) | 1.53 (0.44 to 5.35) | .57 | |
*
BMI = body mass index (weight [kg]/height [m2]); CI = confidence interval; OR = odds ratio; ref = referent.
†
T statistic. All statistical tests were two-sided.
‡
No. of case subjects/No. of noncase subjects.