Calcium supplements and colorectal adenomas. Polyp Prevention Study Group.
Experimental and observational findings suggest that calcium intake may protect against colorectal neoplasia. To investigate this hypothesis, we conducted a randomized, double-blind trial of colorectal adenoma recurrence. Nine hundred thirty patients with a recent history of colorectal adenomas were randomly given calcium carbonate (3 gm daily; 1200 mg elemental calcium) or placebo, with follow-up colonoscopies one and four years after the qualifying examination. The main analysis focused on new adenomas found after the first follow-up endoscopy, up to (and including) the second follow-up examination. Risk ratios of at least one recurrent adenoma and ratios of the average numbers of adenomas were calculated as measures of calcium effect. There was a lower risk of recurrent adenomas in subjects assigned calcium. Eight hundred thirty-two patients had two follow-up examinations and were included in the main analysis; the adjusted risk ratio of one or more adenomas was 0.81 (95% CI 0.67 to 0.99); the adjusted ratio of the average numbers of adenomas was 0.76 (95% CI 0.60 to 0.96). Among subjects who had at least one follow-up colonoscopy, the adjusted risk ratio of one or more recurrent adenomas was 0.85 (95% CI 0.74 to 0.98). The effect of calcium seemed independent of initial dietary fat and calcium intake. No toxicity was associated with supplementation. These findings indicate that calcium supplementation has a modest protective effect against colorectal adenomas, precursors of most colorectal cancers.
Baron
J A
JA
Department of Medicine, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA. john.baron@dartmouth.edu
Beach
M
M
Mandel
J S
JS
van Stolk
R U
RU
Haile
R W
RW
Sandler
R S
RS
Rothstein
R
R
Summers
R W
RW
Snover
D C
DC
Beck
G J
GJ
Frankl
H
H
Pearson
L
L
Bond
J H
JH
Greenberg
E R
ER
D000236:Adenoma / Q000188:drug therapy* / Q000473:pathology*; D000368:Aged; D002118:Calcium / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012306:Risk; D055502:Secondary Prevention; D016896:Treatment Outcome
D002118:Calcium