September: Calcium, Vitamin D Supplementation, and Physical Function in the Women’s Health Initiative

The average lifespan and the percentage of the population in older age categories, has increased in the United States. As one ages, a number of physiological and functional changes can occur. Typically, aging can contribute to increased disability, falls and fractures. Bone health and osteoporotic changes are complex and the changes could be from a variety of factors (genetics, nutrition, activity level, etc.). None the less, research has shown that calcium and vitamin D are most closely related to bone health and with aging. Supplementation is critical to reduce calcium and bone loss and increase physical performance. Physical activity (exercise) also supports bone maintenance, muscle strength, and balance.

This study included 33,067 women, ages 50-79. These women were postmenopausal. They were studied at 40 study centers, in the United States. The calcium and vitamin D trial was a random, double-blind and placebo controlled study. The participants were given 1,000 mg of calcium carbonate, plus 400 IU of vitamin D-3, or a matching placebo of two pills per day were given. Among the subjects, 31.1% were also in hormone therapy only, 54.9% were in dietary modification only, and 14% were in both the hormone therapy and dietary modification trials. Adherence was assessed annually from an interview and the weight of the remaining pills. Physical functioning (the activities the person could or could not perform) was measured with questionnaires at the beginning and again at the end (about 7.1 years) of the study.

This was the first long-term randomized study to examine calcium and vitamin D supplementation in older women. The results of this study did not support the benefit of supplementing calcium and vitamin D to protect against the decline of physical functioning in older women. The level of vitamin D supplementation given to the participants, which was considered adequate at the time the study began, is now considered low. Further studies are needed to measure the effectiveness of calcium and vitamin D supplementation for improving physical functioning.

The additional article, "Calcium and Vitamin D Supplementation for Postmenopausal Bone Health," addresses the prevention and treatment of osteoporosis through calcium and vitamin D supplementation. In the article, it mentions that previous research found calcium and vitamin D to have positive effects on bone health, but current research has been perplexing and unsure of the effects of these supplements. Research is ever-changing, it is important to investigate and interpret the literature properly, and to provide an evidence-based recommendation to patient’s at risk.

JADA Continuing Education Article:
Brunner, R., Cochrane, B., Jackson, R., Larson, J., Lewis, C., Limacher, M., Rosal, M., Shumaker, S., Wallace, R. (2008). Calcium, Vitamin D Supplementation, and Physical Function in the Women’s Health Initiative. Journal of the American Dietetic Association. 108: 1472-1479.

Additional Article:
Kessenich, C. (2007). Calcium and Vitamin D Supplementation for Postmenopausal Bone Health. The Journal for Nurse Practitioners. 3: 155-159.