Table 1.

Baseline characteristics of the cohort overall and by strata of prediagnosis recent BMIa

Prediagnosis recent BMI
Total (N = 5,615)<18.5 (N = 83)18.5–<25 (N = 1,897)25–<30 (N = 2,152)≥30 (N = 1,483)
CategoriesN (%)N (%)N (%)N (%)N (%)Pb
Age at diagnosis, y
 <40559 (10)22 (26.5)244 (12.9)186 (8.6)107 (7.2)P < 0.0001
 40–<501,800 (32.1)26 (31.3)663 (34.9)620 (28.8)491 (33.1)
 50–<601,339 (23.8)6 (7.2)387 (20.4)531 (24.7)415 (28)
 60–<701,312 (23.4)15 (18.1)392 (20.7)553 (25.7)352 (23.7)
 ≥70605 (10.8)14 (16.9)211 (11.1)262 (12.2)118 (8)
Sex
 Men2,928 (52.1)17 (20.5)733 (38.6)1,367 (63.5)811 (54.7)P < 0.0001
 Women2,687 (47.9)66 (79.5)1,164 (61.4)785 (36.5)672 (45.3)
Self-identified race
 White4,549 (81)67 (80.7)1,506 (79.4)1,787 (83)1,189 (80.2)P < 0.0001
 Black or African American376 (6.7)3 (3.6)78 (4.1)140 (6.5)155 (10.5)
 American Indian or Alaskan Native20 (0.4)0 (0)2 (0.1)10 (0.5)8 (0.5)
 More than one race162 (2.9)1 (1.2)63 (3.3)49 (2.3)49 (3.3)
 Unknown, other, or not reported508 (9)12 (14.5)248 (13.1)166 (7.7)82 (5.5)
Educationc
 Less than high school841 (15)13 (15.7)244 (12.9)348 (16.2)236 (15.9)P < 0.0001
 High school graduate1,296 (23.1)17 (20.5)404 (21.3)490 (22.8)385 (26)
 Vocational/technical school1,865 (33.2)30 (36.1)610 (32.2)691 (32.1)534 (36)
 Undergraduate or graduate1,573 (28)22 (26.5)624 (32.9)609 (28.3)318 (21.4)
 Missing40 (0.7)1 (1.2)15 (0.8)14 (0.7)10 (0.7)
Smoking statusd
 Never2,357 (42)33 (39.8)851 (44.9)860 (40)613 (41.3)P < 0.0001
 Former2,056 (36.6)14 (16.9)595 (31.4)870 (40.4)577 (38.9)
 Current1,096 (19.5)35 (42.2)421 (22.2)389 (18.1)251 (16.9)
 Missing106 (1.9)1 (1.2)30 (1.6)33 (1.5)42 (2.8)
Red meat intakee
 <2 servings/week787 (14)22 (26.5)325 (17.1)276 (12.8)164 (11.1)P <0.0001
 2 or 3 servings/week1,963 (35)26 (31.3)696 (36.7)757 (35.2)484 (32.6)
 >3–5 servings/week1,262 (22.5)17 (20.5)403 (21.2)499 (23.2)343 (23.1)
 >5 servings/week1,347 (24)14 (16.9)367 (19.3)533 (24.8)433 (29.2)
 Missing256 (4.6)4 (4.8)106 (5.6)87 (4)59 (4)
Physical activityf
 0–6 METs/week1,207 (21.5)18 (21.7)358 (18.9)446 (20.7)385 (26)P <0.0001
 6.1–20 METs/week765 (13.6)15 (18.1)261 (13.8)272 (12.6)217 (14.6)
 20.1–44 METs/week1,614 (28.7)21 (25.3)583 (30.7)649 (30.2)361 (24.3)
 >44 METs/week1,510 (26.9)20 (24.1)537 (28.3)604 (28.1)349 (23.5)
 Missing519 (9.2)9 (10.8)158 (8.3)181 (8.4)171 (11.5)
Colon or rectal siteg
 Colon3,713 (66.1)57 (68.7)1,234 (65.1)1,402 (65.1)1,020 (68.8)P = 0.08
 Rectum1,902 (33.9)26 (31.3)663 (34.9)750 (34.9)463 (31.2)
TNM summary stageh
 I1,205 (21.5)21 (25.3)424 (22.4)475 (22.1)285 (19.2)P = 0.28
 II1,210 (21.5)18 (21.7)416 (21.9)468 (21.7)308 (20.8)
 III1,431 (25.5)17 (20.5)459 (24.2)565 (26.3)390 (26.3)
 IV609 (10.8)8 (9.6)205 (10.8)214 (9.9)182 (12.3)
 Missing1,160 (20.7)19 (22.9)393 (20.7)430 (20.0)318 (21.4)
MSI status
 MS-stable3,226 (57.5)50 (60.2)1,114 (58.7)1,239 (57.6)823 (55.5)P = 0.41
 MSI-low317 (5.6)4 (4.8)109 (5.7)124 (5.8)80 (5.4)
 MSI-high588 (10.5)6 (7.2)210 (11.1)215 (10)157 (10.6)
 Missing1,484 (26.4)23 (27.7)464 (24.5)574 (26.7)423 (28.5)
BRAF
 Wild-type4,018 (71.6)57 (68.7)1,368 (72.1)1,545 (71.8)1,048 (70.7)P = 0.96
 Mutation396 (7.1)6 (7.2)135 (7.1)149 (6.9)106 (7.1)
 Missing1,201 (21.4)20 (24.1)394 (20.8)458 (21.3)329 (22.2)
  • aDerived from prediagnosis recent body weight (defined as “weight 2 years prior to enrollment”) in kg divided by height in meters squared.

  • bχ2 test for differences across strata.

  • cDefined as the highest completed level of education.

  • dCigarette smoking was defined as ever smoking one cigarette per day for 3 months or longer. Current smoking was indicated when the participant smoked cigarettes in the period two years prior to enrollment (referent period); former smoking was indicated when smoking stopped before the referent period.

  • eOne serving was defined as two to three ounces. Examples of red meat included beef, steak, hamburger, prime rib, and ham.

  • fDerived from responses to total years, total months, and duration per week of nine modes of activity for three periods of the lifespan (20–29, 30–49, 50 years or older).

  • gAccording to International Classification of Diseases for Oncology, Third Edition anatomic site codes: C180, C182, C183, C184, C185, C186, C187, C188, C189, C260 (colon); C199, C209 (rectum).

  • hDerived according to American Joint Commission on Cancer (AJCC) Tumor Node Metastasis (TNM) criteria or converted from SEER summary stage to TNM summary stage.