Calcium plus vitamin D supplementation and health outcomes five years after active intervention ended: The women's health initiative

Jane A. Cauley, Rowan T. Chlebowski, Jean Wactawski-Wende, John A. Robbins, Rebecca J. Rodabough, Zhao Chen, Karen C. Johnson, Mary Jo O'Sullivan, Rebecca D. Jackson, Joann E. Manson

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

Abstract

Background: Clinical outcomes of the Women's Health Initiative (WHI) calcium plus vitamin D supplementation trial have been reported during 7.0 years of active intervention. We now report outcomes 4.9 years after the intervention stopped and cumulative findings. Methods: Postmenopausal women (N=36,282) were randomized; postintervention follow-up continued among 29,862 (86%) of surviving participants. Primary outcomes were hip fracture and colorectal cancer. Breast cancer, all cancers, cardiovascular disease (CVD), and total mortality were predetermined major study outcomes. Results: Hip fracture incidence was comparable in the supplement and the placebo groups, postintervention hazard ratio (HR)=0.95, 95% confidence interval (95% CI: 0.78, 1.15) and overall HR=0.91 (95% CI: 0.79, 1.05). Overall, colorectal cancer incidence did not differ between randomization groups, HR=0.95 (95% CI: 0.80, 1.13). Throughout, there also was no difference in invasive breast cancer, CVD, and all-cause mortality between groups. In subgroup analyses, the invasive breast cancer effect varied by baseline vitamin D intake (p=0.03 for interaction). Women with vitamin D intakes >600 IU/d, had an increased risk of invasive breast cancer, HR=1.28 (95% CI; 1.03, 1.60). Over the entire study period, in post hoc analyses, the incidence of vertebral fractures, HR=0.87 (95% CI: 0.76, 0.98) and in situ breast cancers, HR=0.82 (95% CI: 0.68, 0.99) were lower among women randomized to supplementation. Conclusion: After an average of 11 years, calcium and vitamin D supplementation did not decrease hip fracture or colorectal cancer incidence. Exploratory analyses found lower vertebral fracture and in situ breast cancer incidence in the supplement users. There was no effect on CVD or all-cause mortality.

Original languageEnglish (US)
Pages (from-to)915-929
Number of pages15
JournalJournal of Women's Health
Volume22
Issue number11
DOIs
StatePublished - Nov 1 2013

ASJC Scopus subject areas

  • General Medicine

Fingerprint

Dive into the research topics of 'Calcium plus vitamin D supplementation and health outcomes five years after active intervention ended: The women's health initiative'. Together they form a unique fingerprint.

Cite this