Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


The Effect of Calcium and Vitamin D Supplementation on the Incidence of Rheumatoid Arthritis in the Women's Health Initiative Randomized Study.

Racovan10,  Marius, Walitt10,  Brian, Collins10,  Christopher, Pettinger2,  Mary, Parks4,  Christine, Shikany6,  James, Wactawski-Wende8,  Jean

Brigham and Women's Hospital, Harvard Medical School
Washington Hospital Center
Fred Hutchinson Cancer Research Center
MedStar Research Institute
National Institute of Enviromental Health Sciences
Ohio State University
University of Alabama
University of Arizona
University of Buffalo
University of Pittsburgh

Objective:

To determine if calcium and vitamin D supplementation reduces the incidence of rheumatoid arthritis (RA).

Methods:

32,435 postmenopausal women enrolled in the WHI calcium plus vitamin D (CaD) randomized controlled trial were included in a study with primary endpoints of hip fracture or colorectal cancer. The participants were assigned in a randomized, double-blind manner to either daily 1000 mg of calcium carbonate plus 400 IU of vitamin D3 or placebo. In a post-hoc analysis, a previously validated method was used to identify RA cases using participant self-report plus concomitant use of disease modifying anti-rheumatic drugs (DMARDs). Cox proportional hazards ratios and Kaplan-Meier curves were used to compare the incidence of RA in the treatment versus the placebo groups. Covariates, such as age, hormone therapy, smoking, duration of breastfeeding and geographic location, were considered in the model.

Results:

163 new RA cases were identified over 6 years. No significant differences were observed between the two groups in terms of demographics or non-experimental vitamin D intake (total vitamin D supplementation [p = 0.96], multivitamin intake [p = 0.07] and sun exposure [p= 0.85]). There was no difference between the two groups in RA incidence (p=0.82, Figure 1). Stratification of the results by age, regional solar irradiance and total vitamin D intake and adjustments for covariates such as smoking, hormone therapy, longer duration of breastfeeding did not alter the results.

Conclusions:

Calcium and vitamin D intake as a dietary supplement did not have a statistically significant effect on the incidence of RA in the WHI randomized CaD trial. These results suggest that calcium and low dose vitamin D replacement had no effect on the development of RA in post-menopausal women. Further research is needed to assess the effect of supplementation with higher doses of vitamin D on the incidence of RA.

Figure 1. Cumulative hazard of incident RA.

To cite this abstract, please use the following information:
Racovan, Marius, Walitt, Brian, Collins, Christopher, Pettinger, Mary, Parks, Christine, Shikany, James, et al; The Effect of Calcium and Vitamin D Supplementation on the Incidence of Rheumatoid Arthritis in the Women's Health Initiative Randomized Study. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1062
DOI: 10.1002/art.28829

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