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. Author manuscript; available in PMC: 2015 May 5.
Published in final edited form as: JAMA Intern Med. 2015 May 1;175(5):767–776. doi: 10.1001/jamainternmed.2015.59

Table 2.

Relative Hazard of Incident Cancers of the Colon and Rectum: Vegetarians vs Nonvegetarians

Dietary Patterna No. of Participants HR (95% CI) P Valueb
Total Cancer Cases
Colorectal cancer
  Model 1c
    Vegetarian 40 367 252 0.80 (0.67–0.96) .02
    Nonvegetarian 37 292 238 1 [Reference]
  Model 2d
    Vegetarian 40 367 252 0.78 (0.64–0.95) .01
    Nonvegetarian 37 292 238 1 [Reference]
  Model 3e
    Vegetarian 40 367 252 0.79 (0.64–0.97) .03
    Nonvegetarian 37 292 238 1 [Reference]
Colon cancer
  Model 1c
    Vegetarian 40 367 197 0.80 (0.65–0.97) .04
    Nonvegetarian 37 292 183 1 [Reference]
  Model 2d
    Vegetarian 40 367 197 0.81 (0.65–1.00) .053
    Nonvegetarian 37 292 183 1 [Reference]
  Model 3e
    Vegetarian 40 367 197 0.83 (0.66–1.05) .12
    Nonvegetarian 37 292 183 1 [Reference]
Rectal cancer
  Model 1c
    Vegetarian 40 367 55 0.80 (0.54–1.18) .26
    Nonvegetarian 37 292 55 1 [Reference]
  Model 2d
    Vegetarian 40 367 55 0.71 (0.47–1.06) .09
    Nonvegetarian 37 292 55 1 [Reference]
  Model 3e
    Vegetarian 40 367 55 0.66 (0.43–1.02) .06
    Nonvegetarian 37 292 55 1 [Reference]

Abbreviation: HR, hazard ratio.

a

The dietary patterns are described in the Dietary Data subsection of the Methods section.

b

P value for Wald χ2 test of β coefficient in the Cox proportional hazards regression model.

c

Model 1 was adjusted by age (ie, attained age as time variable), race (black, nonblack), and sex (male, female).

d

Model 2 was adjusted as in model 1 and by educational level (up to high school graduate, trade school/some college/associate degree, or bachelor degree or higher), moderate or vigorous exercise (none, ≤60 min/wk, or >60 min/wk), smoking (never, quit ≥1 year ago, or current or quit <1 year ago), alcohol use (none, <28 servings/mo, or ≥28 servings/mo), family history of colorectal cancer (yes, no), history of peptic ulcer (yes, no), history of inflammatory bowel disease (yes, no), treatment for diabetes mellitus within the past year (yes, no), used aspirin at least weekly at least 2 of the past 5 years (yes, no), used statins at least 2 of the past 5 years (yes, no), prior colonoscopy or flexible sigmoidoscopy (yes, no), supplemental calcium use (yes, no), supplemental vitamin D (micrograms per day), dietary energy (kilocalories per day), and hormone therapy among menopausal women (yes, no).

e

Model 3 was adjusted as in model 2 and by body mass index (calculated as weight in kilograms divided by height in meters squared) (<18.5, 18.5–24.9, 25.0–29.9, or ≥30.0) and fiber intake (<20 g/d, 20 to <30 g/d, 30 to <40 g/d, or ≥40 g/d).