Prevalence of 25(OH) vitamin D (calcidiol) deficiency at time of renal transplantation: a prospective study.

25(OH) Vitamin D (calcidiol) is the major circulating form of vitamin D and is considered the most reliable measure of vitamin D status. Adequate vitamin D status is important for bone health but there is increasing evidence that low serum concentrations of calcidiol (<30 ng/mL) are associated with many adverse health outcomes in the general population. Little is known about calcidiol status at the time of renal transplantation, a period when bone loss is greatest and immunosuppression is highest. We prospectively measured serum calcidiol and parathyroid hormone immediately after transplant from March 2005 onwards. Of 112 patients studied, 29% had calcidiol deficiency (<10 ng/mL), 59% had calcidiol insufficiency (10-29 ng/mL) and only 12% of patients had a normal calcidiol concentration (>30 ng/mL). The prevalence of calcidiol deficiency in black recipients was extremely high at 41%. Serum calcidiol tended to be lower in winter than other seasons. In conclusion, the prevalence of 25(OH) vitamin D (calcidiol) deficiency/insufficiency at the time of renal transplant is very high. The clinical effects of this deficiency/insufficiency deserve further study.