Table 3.
Hazard ratios and 95% confidence intervals for colorectal cancer risk across quintiles of the dietary inflammatory index, excluding colorectal cancer cases which developed within three years from baseline; Women’s Health Initiative, 1993–2010
| Q1 (−7.055, <− 3.139) (healthiest) | Q2 (−3.139, <− 1.997) | Q3 (−1.997, <− 0.306) | Q4 (−0.306, <1.949) | Q5 (1.949, 5.636) (least healthy) | ||
|---|---|---|---|---|---|---|
|
| ||||||
| Referent | a HR (95%b CI) | HR (95%CI) | HR (95%CI) | HR (95%CI) | Ptrend | |
| Colorectal cancer | ||||||
| Age-adjusted modeld | 1.00 | 1.10 (0.94, 1.28) | 1.07 (0.92, 1.25) | 1.10 (0.94, 1.29) | 1.42 (1.23, 1.65)* | <0.0001 |
| Multivariable-adjusted modele | 1.00 | 1.07 (0.91, 1.27) | 1.00 (0.84, 1.19) | 1.04 (0.87, 1.23) | 1.30 (1.09, 1.56)* | 0.008 |
| Colorectal cancer cases, 1462 | 274 (18.7%) | 296 (20.2%) | 273 (18.7%) | 282 (19.3%) | 337 (23.1%) | |
| Colon cancer | ||||||
| Age-adjusted modeld | 1.00 | 1.12 (0.94, 1.33) | 1.05 (0.89, 1.25) | 1.13 (0.95, 1.34) | 1.46 (1.24, 1.72)* | <0.0001 |
| Multivariable-adjusted modele | 1.00 | 1.11 (0.92, 1.33) | 1.00 (0.82, 1.21) | 1.11 (0.92, 1.33) | 1.36 (1.11, 1.66)* | 0.003 |
| Colon cancer cases, 1202 | 222 (18.5%) | 246 (20.5%) | 218 (18.1%) | 239 (19.9%) | 277 (23.0%) | |
| Proximal colon (C18.0–18.4)c | ||||||
| Age-adjusted model | 1.00 | 1.20 (0.96, 1.48) | 0.96 (0.76, 1.21) | 1.20 (0.97, 1.50) | 1.45 (1.17, 1.80)* | 0.0007 |
| Multivariable-adjusted model | 1.00 | 1.18 (0.95, 1.46) | 0.93 (0.74, 1.18) | 1.15 (0.91, 1.44) | 1.38 (1.09, 1.75)* | 0.01 |
| Proximal colon cancer cases, 827d | 153 (18.5%) | 179 (21.6%) | 139 (16.8%) | 168 (20.3%) | 188 (22.7%) | |
| Distal colon (C18.5–18.7)c | ||||||
| Age-adjusted model | 1.00 | 0.91 (0.63, 1.33) | 1.17 (0.82, 1.67) | 1.01 (0.76, 1.58) | 1.23 (0.86, 1.75) | 0.17 |
| Multivariable-adjusted model | 1.00 | 0.86 (0.59, 1.26) | 1.08 (0.75, 1.55) | 0.97 (0.67, 1.41) | 1.03 (0.69, 1.54) | 0.71 |
| Distal colon cancer cases, 296d | 58 (19.6%) | 52 (17.6%) | 65 (22.0%) | 59 (19.9%) | 62 (20.9%) | |
| Rectal cancere | ||||||
| Age-adjusted modeld | 1.00 | 1.00 (0.69, 1.43) | 1.15 (0.81, 1.64) | 1.00 (0.69, 1.44) | 1.27 (0.89, 1.80)* | 0.22 |
| Multivariable-adjusted modele | 1.00 | 0.93 (0.63, 1.38) | 0.99 (0.67, 1.47) | 0.77 (0.51, 1.16) | 1.08 (0.71, 1.65) | 0.96 |
| Rectal cancer cases, 260 | 52 (20.0%) | 50 (19.2%) | 55 (21.5%) | 43 (16.5%) | 60 23.1%) | |
Statistically significant;
hazard ratio and associated 95% confidence interval;
all multivariable models were adjusted for total energy intake, age, body mass index, race/ethnicity, physical activity, educational level, smoking status, family history of colorectal cancer, hypertension, diabetes, arthritis, history of colonoscopy, history of occult blood tests, NSAID use, category and duration of estrogen use, category and duration of estrogen & progesterone use, dietary modification trial arm, hormone therapy trial arm and calcium and vitamin D trial arm;
ICD-O-2 codes used to define location of colon cancer include C18.0 for cecum, C18.2, ascending colon, right colon, C18.3, hepatic flexure of colon, C18.4, transverse colon, C18.5, splenic flexure of colon, C18.6, descending colon, left colon and C18.7, sigmoid colon;
proximal and distal colon cancer cases do not add up to the total number of colon cancer cases because of missing ICD codes and codes C18.8 and C18.9 for large intestine Not Otherwise Specified, were not included;
rectal cancer include all rectum and rectosigmoid cases.