The association of calcium and vitamin D, and colon and rectal cancer in Wisconsin women.
BACKGROUND
Calcium and vitamin D have been hypothesized to reduce colorectal cancer risk. Epidemiological evidence, however, is mixed.


METHODS
To explore those relationships, data were collected as part of a population-based, case-control study of colorectal cancer in Wisconsin women (678 controls, 348 colon and 164 rectal cancer cases). A semi-quantitative food frequency questionnaire was used to ascertain food and dietary supplement intake 2 years prior to interview. Logistic regression models were used to calculate odds ratios (OR).


RESULTS
Higher levels of calcium intake were associated with reduced colon and rectal cancer risk. The following adjusted OR and 95% confidence intervals (CI) were observed, comparing the fifth quintile (based on control intake) with the first: colon cancer: OR = 0.6, 95% CI: 0.4-1.0, P-trend: 0.03; rectal cancer: OR = 0.6, 95% CI: 0.3-1.1, P-trend: 0.07. Similar relationships were observed for vitamin D intake, although OR were closer to the null value and did not always behave in a step-wise fashion (fifth quintile versus the first--colon cancer: OR = 0.7, 95% CI: 0.4-1.1, P-trend: 0.05; rectal cancer: OR = 0.8, 95% CI: 0.5-1.5, P-trend: 0.42).


CONCLUSIONS
These data support a protective association of calcium on colon and rectal cancer risk.
Marcus
P M
PM
University of Wisconsin Comprehensive Cancer Center, Madison 53792, USA.
Newcomb
P A
PA
D000368:Aged; D002136:Calcium, Dietary; D016022:Case-Control Studies; D003110:Colonic Neoplasms / Q000453:epidemiology*; D004435:Eating; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D012004:Rectal Neoplasms / Q000453:epidemiology*; D014807:Vitamin D; D014922:Wisconsin / Q000453:epidemiology
D002136:Calcium, Dietary; D014807:Vitamin D