Table 3.
Relative risks for colon cancer by imazethapyr intensity weighted lifetime exposure days (IWED) and site of origin among AHS participants, 1993-2004a
| Cancer Site | IWED | Cases (n) | Multivariate Adjusted RR (95% CI)b |
|---|---|---|---|
| Proximal Colonc | No Exposure | 64 | 1.00 |
| T1 | 13 | 1.27 (0.69, 2.34) | |
| T2 | 17 | 1.90 (1.09, 3.29) | |
| T3 (lower half) | 7 | 1.45 (0.65, 3.21) | |
| T3 (upper half) | 11 | 2.73 (1.42, 5.25) | |
| p for trend | 0.001 | ||
| Distal Colond | No Exposure | 69 | 1.00 |
| T1 | 8 | 0.61 (0.29, 1.27) | |
| T2 | 9 | 0.76 (0.38, 1.54) | |
| T3 (lower half) | 5 | 0.75 (0.30, 1.88) | |
| T3 (upper half) | 7 | 1.21 (0.55, 2.68) | |
| p for trend | 0.75 |
Abbreviations (alphabetical): Agricultural Health Study (AHS); Confidence
Interval (CI); Rate Ratio (RR). IWED categories are defined as: <54.1 (T1), 54.1 to <152.9 (T2), 152.9 to <311.9 (T3 lower half), and ≥ 311.9 (T3 upper half).
a
Excludes Not Otherwise Specified Colon (n=6) and Overlapping lesion of colon (N=4).
b
Adjusted for age, enrollment year, and race, chlorpyrifos use and aldicarb use.
c
Includes cecum, appendix, ascending colon, hepatic flexure and transverse colon.
d
Includes splenic flexure, descending colon and sigmoid colon.