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	Return to Search Result Full Text PDF PDA Full Text PowerPoint Slide Set Editorial by Forman, M. R. Letters Add to Personal Archive Add to Citation Manager Notify a Friend E-mail When Cited E-mail When Letters Appear Related Article PubMed Citation

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 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 [ClinicalTrials.gov] .)

Source Information

Address reprint requests to Dr. Wactawski-Wende at the Department of Social and Preventive Medicine, University at Buffalo, 270 Farber Hall, Buffalo, NY 14214, or at jww{at}buffalo.edu.

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Calcium plus Vitamin D and the Risk of Colorectal Cancer
Holick M. F., Giovannucci E., Wactawski-Wende J., Anderson G. L., O'Sullivan M.
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N Engl J Med 2006; 354:2287-2288, May 25, 2006. Correspondence

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