Book Review

Vitamin D

N Engl J Med 1998; 339:856September 17, 1998

Article

Vitamin D
Edited by David Feldman, with Francis H. Glorieux and J. Wesley Pike. 1285 pp., illustrated. San Diego, Calif., Academic Press, 1997. $175. ISBN: 0-12-252685-6

A colleague of mine, after attending a lecture on bone disease, remarked that the vitamin D pathways looked just like chicken wire — an apt observation, because it emphasizes that this “vital amine” is actually a steroid hormone with complex metabolism and multisystemic effects. Vitamin D, a new textbook edited by Feldman, Glorieux, and Pike, has enough chicken wire to fence in a farm, but most of it is very interesting. There are about 30 naturally occurring metabolites of vitamin D and more than 800 synthetic analogues designed to treat a variety of diseases, ranging from rickets to cancer. A slight twist in the molecule, an extra double bond, or an additional carbon atom can change the metabolism, the half-life, the pattern of binding to vitamin D–binding protein, the action of the vitamin D receptor, or perhaps the heterodimer formation and attachment to the vitamin D–response elements on the DNA. These structure–function relations, as well as each step of vitamin D metabolism and action, are clearly detailed in the book.

The chapters are generally well written, beginning with the remarkable history of vitamin D and ending with summaries of preliminary clinical trials of the new vitamin D analogues that have the potential to treat cancer. In between are sections on physiology and clinical disorders related to vitamin D. Some of the best chapters are those by the editors, including the introduction to the vitamin D receptor by Pike, “Vitamin D Pseudodeficiency” by Glorieux and St.-Arnaud, and “Hereditary 1,25-Dihydroxyvitamin D Resistant Rickets” by Malloy, Pike, and Feldman. Other highlights include the discussion of calcium economy by Heaney, the explanation of dimerization by Freedman and Lemon, the review of vitamin D insufficiency in the elderly by Chapuy and Meunier, the collection of radiographs of patients with rickets by Judith Adams, and the chapter about the role of vitamin D in lymphoproliferative diseases by John Adams.

The chapter on vitamin D and osteoporosis was disappointing. The authors did not provide details about clinical trials of vitamin D, calcitriol, or 1α-hydroxyvitamin D. Tables showing research evidence would have been helpful. The authors concluded that calcitriol in doses of 0.75 μg per day was effective and safe, but in one of the largest studies they cited, many women had to have the dose reduced to 0.25 μg per day because hypercalciuria or hypercalcemia developed at higher doses.

Because X-linked hypophosphatemic rickets is the most common genetic disorder related to vitamin D, I was surprised that a chapter was not devoted to it. There was merely a scant description of the clinical presentation and treatment of the disease in a list of other disorders of phosphate homeostasis.

Although some redundancy is to be expected in a large, multiauthored book, there is more than necessary in this one. For example, there were more copies of the table of vitamin D–response elements than editors of the book. Each of the chapters on the use of vitamin D for a specific cancer repeated the general mechanisms of vitamin D action on malignant tissue. The section on the target organs overlapped considerably with that on the disorders of these organs. This redundancy, however, is more obvious to a reviewer who reads the book straight through than to a clinician or investigator who uses it as a reference tool.

Overall, the book provides a comprehensive introduction to vitamin D. It will be especially useful for clinical investigators who would like a review of the metabolism of vitamin D so that they can keep abreast of rapid new developments and for basic scientists who are entering the field. It will also be a helpful resource for clinicians in medical specialties that previously did not involve vitamin D metabolism (such as oncology and dermatology), because these physicians may soon be using the new analogues.

Susan Ott, M.D.
University of Washington, Seattle, WA 98195