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Colorectal Cancer Prevention (PDQ®): Prevention - Health Professional Information [NCI] - Overview



The evidence is fair that elemental calcium without vitamin D as a supplement in the level of 1,000 to 1,200 mg/day increases the risk of myocardial infarction. Based on fair evidence, calcium supplementation with vitamin D at doses less than 1,000 has few harms.

Magnitude of Effect: In a meta-analysis of RCTs of calcium alone, the risk of myocardial infarction was increased from 4.8% to 5.8% (HR = 1.31; 95% CI, 1.02–1.67).

Study Design: Pooled and individual prospective cohort studies plus RCTs.
Internal Validity: Good.
Consistency: Poor (one meta-analysis of 11 RCTs for calcium alone found increased myocardial infarction; no other individual studies found this).[34]
External Validity: Good.



Based on solid evidence, statins do not reduce the incidence or mortality from CRC.

Study Design: Meta-analyses of RCTs.[35,36,37]
Internal Validity: Good.
Consistency: Good.
External Validity: N/A.


Based on solid evidence, the harms of statins are small.

Study Design: Observational studies [38], multiple RCTs, and a review.[39]
Internal Validity: Good.
Consistency: Good.
External Validity: Good.


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Last Updated: February 25, 2014
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