The aim of this study was to determine the associations between calcium + vitamin D supplementation (vs placebo) and height loss in 36,282 participants of the Women's Health Initiative Calcium and Vitamin D trial.
Post hoc analysis of data from a double-blind randomized controlled trial of 1,000 mg of elemental calcium as calcium carbonate with 400 IU of vitamin D3 daily (CaD) or placebo in postmenopausal women at 40 US clinical centers. Height was measured annually (mean follow-up 5.9 y) with a stadiometer.
Average height loss was 1.28 mm/y among participants assigned to CaD versus 1.26 mm/y for women assigned to placebo (P = 0.35). Effect modification of the CaD intervention was not observed by age, race/ethnicity, or baseline intake of calcium or vitamin D. Randomization to the CaD group did not reduce the risk of clinical height loss (loss of ≥1.5 inches [3.8 cm]: hazard ratio (95% CI) = 1.00 (0.81, 1.23). A strong association (P < 0.001) was observed between age group and height loss. When we censored follow-up data in participants who became nonadherent to study pills, the results were similar to those of our primary analysis.
Compared with placebo, the CaD supplement used in this trial did not prevent height loss in healthy postmenopausal women.
1Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at University of California, Los Angeles, CA
2WHI Clinical Coordinating Center, Fred Hutchinson Cancer Research Center, Seattle, WA
3Endocrine, Skeletal Health and Osteoporosis Center, Brigham and Women's Hospital, Boston, MA
4Division of Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester, MA
5Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, Buffalo, NY
6Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA
7HealthPartners Institute, Minneapolis, MN
8Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
Address correspondence to: Carolyn J. Crandall, MD, MS, David Geffen School of Medicine at University of California, UCLA Medicine/GIM, 911 Broxton Ave, 1st floor, Los Angeles, CA 90024. E-mail: firstname.lastname@example.org
Received 30 March, 2016
Revised 2 May, 2016
Accepted 2 May, 2016
Study conception and design—C.J.C.; acquisition of data—J.W.W., M.S.L., J.A.C., K.L.M., J.E.M., J.A.C.; statistical analysis—C.A. and A.A.; data interpretation—C.J.C., A.K.A., M.S.L., W.L., J.W.W., J.A.C., K.L.M., and J.E.M.; drafting of manuscript—C.J.C.; critical revision of manuscript for important intellectual content—C.J.C., A.K.A., M.S.L., W.L., J.W.W., J.A.C., K.L.M., and J.E.M.
Funding/support: The WHI program is funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, US Department of Health and Human Services through contracts HHSN268201100046C, HHSN268201100001C, HHSN268201100002C, HSN268201100003C, HHSN268201100004C, and HH SN271201100004C.
Financial disclosure/conflicts of interest: M.S.L. at Brigham and Women's Hospital has received funding from the NIH determining effects of randomized vitamin D supplementation in on bone density structure and architecture and for prevention of fractures. J.E.M. at Brigham and Women's Hospital receive funding from the NIH for a randomized trial of vitamin D supplementation in the prevention of cancer and cardiovascular disease. C.J.C., W.L., J.W.W., K.L.M., J.A.C., and A.K.A. report no conflicts of interest.