Dietary risk factors for colon and rectal cancers: a comparative case-control study.
BACKGROUND
In Japan, the incidence rate of colon cancer has more rapidly increased than that of rectal cancer. The differential secular trends may be due to different dietary factors in the development of colon and rectal cancers.


METHODS
To compare dietary risk factors between colon and rectal cancers, we undertook a case-control study at Aichi Cancer Center Hospital, Japan. Subjects were 507 patients with newly diagnosed colon (n = 265) and rectal (n = 242) cancers, and 2,535 cancer-free outpatients (controls). Intakes of nutrients and food groups were assessed with a food frequency questionnaire, and multivariate-adjusted odds ratios (ORs) were estimated using unconditional logistic models.


RESULTS
We found a decreasing risk of colon cancer with increasing intakes of calcium and insoluble dietary fiber; the multivariate ORs across quartiles of intake were 1.00, 0.90, 0.80, and 0.67 (trend p = 0.040), and 1.00, 0.69, 0.64, and 0.65 (trend p = 0.027), respectively. For rectal cancer, a higher consumption of carotene and meat was associated with a reduced risk; the corresponding ORs were 1.00, 1.10, 0.71, and 0.70 for carotene (trend p = 0.028), and 1.00, 0.99, 0.68, and 0.72 for meat (trend p = 0.036). Carbohydrate intake was positively correlated with the risk of rectal cancer (ORs over quartiles: 1.00, 1.14, 1.42, and 1.54; trend p = 0.048). This association was stronger in women, while fat consumption was inversely correlated with the risk of female colon and rectal cancers.


CONCLUSIONS
Dietary risk factors appear to considerably differ between colon and rectal cancers.
Wakai
Kenji
K
Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan. wakai@aichi-cc.jp
Hirose
Kaoru
K
Matsuo
Keitaro
K
Ito
Hidemi
H
Kuriki
Kiyonori
K
Suzuki
Takeshi
T
Kato
Tomoyuki
T
Hirai
Takashi
T
Kanemitsu
Yukihide
Y
Tajima
Kazuo
K
D000328:Adult; D000368:Aged; D002136:Calcium, Dietary / Q000008:administration & dosage; D002338:Carotenoids / Q000008:administration & dosage; D016022:Case-Control Studies; D003110:Colonic Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D004032:Diet / Q000145:classification*; D004043:Dietary Fiber / Q000008:administration & dosage; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005502:Food / Q000145:classification*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D008460:Meat; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D011795:Surveys and Questionnaires
D002136:Calcium, Dietary; D004043:Dietary Fiber; D002338:Carotenoids