• Incorporate chronic disease indicators when the data allow; and

• Highlight concepts of probability and risk for defining reference values.

With this new model as a backdrop, the IOM in 1997 issued the first set of DRIs. The nutrients included in the first of what became a series of DRI reports were: calcium, phosphorus, magnesium, vitamin D, and fluoride (IOM, 1997). Therefore, the 1997 DRIs for calcium and vitamin D—the nutrients that are the topic of this 2010 review—have been in existence for 13 years. In 2008, the U.S. and Canadian governments made the decision that there were now sufficient new data to warrant funding another study of the DRIs for vitamin D (Yetley et al., 2009). They included calcium in this study because of its close inter-relationship with vitamin D. A 14-member ad hoc expert committee was convened by the IOM in 2009 to take on this task; its work was to be completed by 2010. Committee members had general expertise in the areas of vitamin D and calcium or a closely related topic area, with specific expertise related to endocrinology, bone and skeletal health, immunology, oncology, dermatology, cardiovascular health, pregnancy and reproductive nutrition, pediatrics and infant nutrition, epidemiology, cellular metabolism, toxicology and risk assessment, nutrition monitoring, biostatistics, and minority health and health disparities. Three members of the committee had served on other DRI committees.

The current consideration of the DRIs for vitamin D and calcium takes place at a time when the interest in vitamin D is enormous. This vitamin—with its hormone-related activities—has received much media attention and has been the subject of countless publications and lay press reporting of its benefits for an array of health outcomes. Concerns about widespread vitamin D deficiency in North American populations are often expressed. This committee’s focus was, first, to review objectively the existing evidence concerning the benefits and health outcomes associated with vitamin D as well as calcium, using the well-established scientific principles for judging the quality and relevance of data from intervention as well as observational studies. The members of the committee next integrated the available data and, within the context of the risk assessment approach for establishing DRIs, carried out activities to specify DRIs for calcium and vitamin D. The reference values established in 1997 were noted by the committee, but they were not binding on the committee’s work.

The charge to the committee was to assess current relevant data and update, as appropriate, the DRIs for vitamin D and calcium. The review was to include consideration of chronic disease indicators (e.g., reduction