Approximately 10 million Americans over the age of 50 have osteoporosis, a condition that causes bones to become weak and more likely to break[i]. In fact, two million bone breaks occur every year in the U.S. due to osteoporosis, often resulting in immobility, pain, placement in a nursing home, isolation and other health problems. Scientific evidence has established that calcium and vitamin D are needed for growth and maintenance of healthy bone tissue[ii].
NOF recognizes and appreciates the importance and need to further study the effect of nutrition on bone health and fracture prevention. We also recognized it is particularly difficult to study nutrients and even more difficult to interpret meta-analyses that combine studies that are different from one another in aspects such as type of subject, dose of supplements, evaluation/control of intervening variables, length of follow up, etc.
In a recently published study in the Journal of the American Medical Association (JAMA), Dr. Jia-Guo Zhao et al, used data from 33 prior studies including the Women’s Health Initiative (WHI), and found no significant relationship between calcium and vitamin D supplementation and fracture incidence. It is important to note that this study looked at healthy, community dwelling individuals and does not address people with osteoporosis. Moreover, baseline vitamin D levels were not measured in all study participants, and those who are not deficient in calcium or vitamin D, including many in the WHI, are not likely to benefit from supplementation. Also, Dr. Zhao et al. use data where patients were treated for less than six months, which is likely not long enough to have an effect on fractures.
In contrast, NOF’s rigorous analysis of randomized trials in its 2015 paper published in the journal, Osteoporosis International, Calcium plus Vitamin D Supplementation and Risk of Fractures: An Updated Meta-Analysis from the National Osteoporosis Foundation, found a significant risk reduction in fractures with calcium and vitamin D. In this study, NOF updated a former evidence report published in 2011 by the U.S. Agency for Healthcare Research and Quality with new clinical trial data. The NOF study excluded those who were taking their own supplements and those who had previous fractures, which increases their risk of future fractures. The NOF study also considered adherence to study protocols. These results strongly suggested that calcium plus vitamin D supplementation in select populations can significantly reduce the risk of total fractures by 16% and hip fractures by 32%.
[i] Wright, N. C., Looker, A. C., Saag, K. G., Curtis, J. R., Delzell, E. S., Randall, S., & Dawson-Hughes, B. (2014). The Recent Prevalence of Osteoporosis and Low Bone Mass in the United States Based on Bone Mineral Density at the Femoral Neck or Lumbar Spine. Journal of Bone and Mineral Research : The Official Journal of the American Society for Bone and Mineral Research, 29(11), 2520–2526. http://doi.org/10.1002/jbmr.2269
[ii] C. M. Weaver, C. M. Gordon, K. F. Janz, H. J. Kalkwarf, J. M. Lappe, R. Lewis, M. O’Karma, T. C. Wallace and B. S. Zemel. The National Osteoporosis Foundation’s position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations. Osteoporosis Int. 2016; 27: 1281–1386.