Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial

• Published in: The American journal of clinical nutrition 2007-06, Vol.85 (6), p.1586-1591
• Main Authors: Lappe, Joan M, Travers-Gustafson, Dianne, Davies, K Michael, Recker, Robert R, Heaney, Robert P
• Format: Article
• Language: English
• Subjects: adults; Biological and medical sciences; blood chemistry; bone fractures; Calcifediol - blood; calcium; Calcium - therapeutic use; calcium and vitamin D3supplementation; cancer; Dietary Supplements; disease diagnosis; disease incidence; Double-Blind Method; elderly; elderly nutrition; Feeding. Feeding behavior; Female; Fractures, Bone - prevention & control; Fundamental and applied biological sciences. Psychology; Humans; Incidence; Kaplan-Meier Estimate; Logistic Models; Middle Aged; neoplasms; Neoplasms - epidemiology; Neoplasms - prevention & control; nutrient-nutrient interactions; regression analysis; risk reduction; rural women; Serum 25-hydroxyvitamin D; Vertebrates: anatomy and physiology, studies on body, several organs or systems; vitamin D; Vitamin D - therapeutic use; vitamin-mineral supplements; women
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/85.6.1586

Background:Numerous observational studies have found supplemental calcium and vitamin D to be associated with reduced risk of common cancers. However, interventional studies to test this effect are lacking. Objective:The purpose of this analysis was to determine the efficacy of calcium alone and calcium plus vitamin D in reducing incident cancer risk of all types. Design:This was a 4-y, population-based, double-blind, randomized placebo-controlled trial. The primary outcome was fracture incidence, and the principal secondary outcome was cancer incidence. The subjects were 1179 community-dwelling women randomly selected from the population of healthy postmenopausal women aged >55 y in a 9-county rural area of Nebraska centered at latitude 41.4°N. Subjects were randomly assigned to receive 1400–1500 mg supplemental calcium/d alone (Ca-only), supplemental calcium plus 1100 IU vitamin D3/d (Ca + D), or placebo. Results:When analyzed by intention to treat, cancer incidence was lower in the Ca + D women than in the placebo control subjects (P< 0.03). With the use of logistic regression, the unadjusted relative risks (RR) of incident cancer in the Ca + D and Ca-only groups were 0.402 (P= 0.01) and 0.532 (P= 0.06), respectively. When analysis was confined to cancers diagnosed after the first 12 mo, RR for the Ca + D group fell to 0.232 (CI: 0.09, 0.60; P< 0.005) but did not change significantly for the Ca-only group. In multiple logistic regression models, both treatment and serum 25-hydroxyvitamin D concentrations were significant, independent predictors of cancer risk. Conclusions:Improving calcium and vitamin D nutritional status substantially reduces all-cancer risk in postmenopausal women. This trial was registered at clinicaltrials.govas NCT00352170.