Calcium plus vitamin D supplementation and the risk of colorectal cancer.
N Engl J Med
; 354(7): 684-96, 2006 Feb 16.
Article
in En
| MEDLINE
| ID: mdl-16481636
ABSTRACT
BACKGROUND:
Higher intake of calcium and vitamin D has been associated with a reduced risk of colorectal cancer in epidemiologic studies and polyp recurrence in polyp-prevention trials. However, randomized-trial evidence that calcium with vitamin D supplementation is beneficial in the primary prevention of colorectal cancer is lacking.METHODS:
We conducted a randomized, double-blind, placebo-controlled trial involving 36,282 postmenopausal women from 40 Women's Health Initiative centers 18,176 women received 500 mg of elemental calcium as calcium carbonate with 200 IU of vitamin D3 [corrected] twice daily (1000 mg of elemental calcium and 400 IU of vitamin D3) and 18,106 received a matching placebo for an average of 7.0 years. The incidence of pathologically confirmed colorectal cancer was the designated secondary outcome. Baseline levels of serum 25-hydroxyvitamin D were assessed in a nested case-control study.RESULTS:
The incidence of invasive colorectal cancer did not differ significantly between women assigned to calcium plus vitamin D supplementation and those assigned to placebo (168 and 154 cases; hazard ratio, 1.08; 95 percent confidence interval, 0.86 to 1.34; P=0.51), and the tumor characteristics were similar in the two groups. The frequency of colorectal-cancer screening and abdominal symptoms was similar in the two groups. There were no significant treatment interactions with baseline characteristics.CONCLUSIONS:
Daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal women. The long latency associated with the development of colorectal cancer, along with the seven-year duration of the trial, may have contributed to this null finding. Ongoing follow-up will assess the longer-term effect of this intervention. (ClinicalTrials.gov number, NCT00000611.).
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Vitamin D
/
Calcium Carbonate
/
Colorectal Neoplasms
/
Adenocarcinoma
Type of study:
Clinical_trials
/
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Aged
/
Female
/
Humans
/
Middle aged
Language:
En
Journal:
N Engl J Med
Year:
2006
Document type:
Article
Affiliation country:
United States
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA