CONCLUSIONS Dietary calcium intake is not associated with risk of fracture , and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures .
OBJECTIVE To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures .
Health risks and benefits from calcium and vitamin D supplementation: Women's Health Initiative clinical trial and cohort study
Summary The Women 's Health Initiative ( WHI ) double-blind , placebo-controlled clinical trial r and omly assigned 36,282 postmenopausal women in the U.S. to 1,000 mg elemental calcium carbonate plus 400 IU of vitamin D3 daily or placebo , with average intervention period of 7.0 years . The trial was design ed to test whether calcium plus vitamin D supplementation in a population in which the use of these supplements was widespread would reduce hip fracture , and secondarily , total fracture and colorectal cancer . Introduction This study further examines the health benefits and risks of calcium and vitamin D supplementation using WHI data , with emphasis on fractures , cardiovascular disease , cancer , and total mortality . Methods WHI calcium and vitamin D r and omized clinical trial ( CT ) data through the end of the intervention period were further analyzed with emphasis on treatment effects in relation to duration of supplementation , and these data were contrasted and combined with corresponding data from the WHI prospect i ve observational study ( OS ) . Results Among women not taking personal calcium or vitamin D supplements at baseline , the hazard ratio [ HR ] for hip fracture occurrence in the CT following 5 or more years of calcium and vitamin D supplementation versus placebo was 0.62 ( 95 % confidence interval ( CI ) , 0.38–1.00 ) . In combined analyses of CT and OS data , the corresponding HR was 0.65 ( 95 % CI , 0.44–0.98 ) . Supplementation effects were not apparent on the risks of myocardial infa rct ion , coronary heart disease , total heart disease , stroke , overall cardiovascular disease , colorectal cancer , or total mortality , while evidence for a reduction in breast cancer risk and total invasive cancer risk among calcium plus vitamin D users was only suggestive . Conclusion Though based primarily on a subset analysis , long-term use of calcium and vitamin D appears to confer a reduction that may be substantial in the risk of hip fracture among postmenopausal women . Other health benefits and risks of supplementation at doses considered , including an elevation in urinary tract stone formation , appear to be modest and approximately balanced
CONCLUSIONS Dietary calcium intake is not associated with risk of fracture , and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures .
OBJECTIVE To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures .