Vitamin D in Chronic Kidney Disease

Vitamin D deficiency, circulating levels lower than 15 ng/ml, is an epidemic disease worldwide with  more than a billion people suffering of it in the beginning of the 21-century. Besides its impact on mineral and bone metabolism, these low vitamin D levels are also associated with a diversity of non-skeletal complications, among them cardiovascular disease, diabetes mellitus, multiple sclerosis, cancer, tuberculosis, and immune system dysfunction. Chronic Kidney Disease is also a very common disease, affecting more than 10% of the world population, ranging from stage 1 to stage 5 before dialysis. Approximately 1% of the population in industrialized countries is affected by end-stage renal disease (ESRD), needing a renal replacement therapy either hemodialysis or peritoneal dialysis, and ultimately by renal transplantation. Those CKD patients are more susceptible to exhibit reduced vitamin D stocks. Consequently, more than eighty percent of CKD patients have either insufficient or deficient vitamin D levels for multiple reasons.

Pablo URENA TORRES, M.D., Ph.D.
Department of Nephrology and Dialysis. Clinique du Landy. 23, rue du Landy. 93400 Saint Ouen, France, and Department of Department of Renal Physiology. Necker Hospital, University of Paris Descartes, Paris, France

Mario COZZOLINO, M.D. Ph.D.
Department of Health Sciences, Renal Division, San Paolo Hospital, University of Milan, Milan, Italy

Marc G. VERVLOET, M.D., Ph.D.
Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands