Table 3.
Associations of OBS Measures With Incident, Sporadic Colorectal Adenoma in Data From 3 Case-Control Studies (CPRU Study, 1991–1994; MAP I Study, 1994–1997; and MAP II Study, 2002)
| OBSa | CPRU Study |
MAP Studies |
Pooled Data |
||||||
|---|---|---|---|---|---|---|---|---|---|
| No. of Cases | RRb | 95% CI | No. of Cases | RRb | 95% CI | No. of Cases | RRb | 95% CI | |
| OBS–equal weight | |||||||||
| Tertile 1 | 258 | 1.00 | Referent | 102 | 1.00 | Referent | 360 | 1.00 | Referent |
| Tertile 2 | 182 | 0.68 | 0.53, 0.87 | 65 | 0.67 | 0.43, 1.07 | 247 | 0.67 | 0.54, 0.83 |
| Tertile 3 | 124 | 0.51 | 0.39, 0.68 | 58 | 0.67 | 0.41, 1.09 | 182 | 0.54 | 0.43, 0.69 |
| Ptrend | <0.0001 | 0.09 | <0.0001 | ||||||
| OBS–lit. review | |||||||||
| Tertile 1 | 301 | 1.00 | Referent | 141 | 1.00 | Referent | 442 | 1.00 | Referent |
| Tertile 2 | 150 | 0.62 | 0.47, 0.81 | 36 | 0.32 | 0.19, 0.53 | 186 | 0.53 | 0.42, 0.67 |
| Tertile 3 | 113 | 0.47 | 0.35, 0.64 | 48 | 0.44 | 0.27, 0.73 | 161 | 0.45 | 0.35, 0.58 |
| Ptrend | <0.0001 | <0.001 | <0.0001 | ||||||
| OBS–a posteriori | |||||||||
| Tertile 1 | 299 | 1.00 | Referent | 122 | 1.00 | Referent | 421 | 1.00 | Referent |
| Tertile 2 | 164 | 0.57 | 0.44, 0.74 | 66 | 0.56 | 0.36, 0.88 | 230 | 0.57 | 0.46, 0.71 |
| Tertile 3 | 101 | 0.40 | 0.30, 0.53 | 37 | 0.34 | 0.21, 0.57 | 138 | 0.38 | 0.29, 0.49 |
| Ptrend | <0.0001 | <0.0001 | <0.0001 | ||||||
| OBS–Bayesian | |||||||||
| Tertile 1 | 305 | 1.00 | Referent | 139 | 1.00 | Referent | 444 | 1.00 | Referent |
| Tertile 2 | 150 | 0.57 | 0.43, 0.73 | 35 | 0.27 | 0.16, 0.46 | 185 | 0.47 | 0.38, 0.60 |
| Tertile 3 | 109 | 0.45 | 0.34, 0.60 | 51 | 0.47 | 0.29, 0.76 | 160 | 0.45 | 0.35, 0.58 |
| Ptrend | <0.0001 | <0.001 | <0.0001 | ||||||
Abbreviations: CI, confidence interval; CPRU, Cancer Prevention Research Unit; MAP, Markers of Adenomatous Polyps; OBS, oxidative balance score; RR, relative risk.
a OBS–equal weight: all OBS components received equal weights; OBS–lit. review: weights for OBS components were based on effect estimates derived from literature review; OBS–a posteriori: weights for OBS components were based on CPRU Study data; OBS–Bayesian: weights for OBS components were based on Bayesian analysis of case-control data. Tertiles for OBS are sex-specific, and the dietary components were adjusted for total energy intake.
b Adjusted for age, sex, education, family history of colorectal cancer in a first-degree relative, regular aspirin use, regular use of nonsteroidal antiinflammatory drugs, total calcium intake, total vitamin D intake, total energy intake, total folate intake, dietary fiber intake, and hormone therapy (among women).