Preface

Vitamin D is the subject of great controversy. Initially, the controversy was based on the difficulty of obtaining accurate measurements of vitamin D. Then, subsequent discovery of multiple hydroxylated products led to confusion as to which are the most clinically important forms. Least controversial was the effect of vitamin D deficiency on bone formation. Finally, an explosion of reports on extraskeletal pathophysiology have suggested that vitamin D has a great impact on multiple tissues and organ function that can worsen diseases and affect mortality.

This book is organized into four sections: Section 1 "The Growing Importance of Vitamin D"; Section 2 "Extraskeletal Effects of Vitamin D Deficiency"; Section 3 "New Frontiers of Vitamin D Research"; and Section 4 "Clinical Application of Measurement of Vitamin D and Replacement." Chapters in these sections cover the earliest investigations of vitamin D, the extraskeletal consequences of vitamin D, and the impact of correction of vitamin D deficiency on overall health and mortality.

A unique theme developed in Section 2 is the similarity of vitamin D's structure to steroid molecules, including sex hormone structures. This is further discussed in the chapters on the effect of vitamin D on physical performance, its psychological impact on behavior, and its role in metabolism and response to stress. An important future area of research into both skeletal and extraskeletal consequences of vitamin D deficiency is a chapter on the study of vitamin D in space. Finally, clinical application of measurement and treatment is presented in the replacement of vitamin D to patients with rheumatologic problems and systemic problems such as those in the intensive care unit.

This book presents a concise summary of a broad body of international research that reports advantages as well as disadvantages of vitamin D in skeletal and extraskeletal tissue physiology.

**II**

**Chapter 7 95**

Extraskeletal Effects of Vitamin D Deficiency in Intensive Care Patients

*by Edward T. Zawada*

**Edward T. Zawada Jr. M.D., M.A.C.P.** Professor and Chairman Emeritus, Department of Internal Medicine, University of South Dakota, Sanford School of Medicine, Nephrologist and Intensivist, Shasta Critical Care Specialists, Redding, California

**1**

Section 1

Growing Importance of

Vitamin D
