Insufficient levels of 25-hydroxyvitamin D found in majority of Danish kidney allograft recipient.
BARCELONA—Most renal transplant patients in Denmark have inadequately low vitamin D levels, according to researchers who say routine supplementation may be required to mitigate the adverse clinical consequences.
Bettina Ewers, MSc, a research assistant at Copenhagen University Hos-pital in Herlev, and colleagues iden-tified determinants of low vitamin D in 173 kidney transplant recipients (mean age 53 years) who had their grafts for a median of 7.4 years.
After adjusting analyses for possible confounders, they found that 51% of the group had insufficient vitamin D concentrations—defined by Kidney Disease Outcome Quality Initiative guidelines as serum levels of 25-hydroxyvitamin D (25-OHD) between 40 and 75 nmol/L. Another 29% had moderate to severe vitamin D deficiency, defined as serum 25-OHD levels of 39 nmol/L or less.
These deficiencies occurred even though 69% of the women and 51% of the men were already taking ergocalciferol supplements, Ewers pointed out. Patients who avoided the sun—as transplantation patients are all instructed to do to reduce their risk of skin cancer—were more likely to be vitamin D deficient than those who did not avoid the sun. She presented findings here at the 44th Congress of the European Renal Association-European Dialysis and Transplant Association.
Nevertheless, sun exposure still did not guarantee that patients would have adequate levels of vitamin D, Ewers noted, and dietary sources of vitamin D have a relatively limited effect on vitamin D concentrations. With this in mind, Ewers and colleagues recommended that ergocalciferol at doses of 22-30 µg/day be routinely prescribed to ensure kidney transplant recipients achieve a serum 25-OHD level of at least 75 nmol/L.
In the winter, the prevalence of vitamin D deficiency in the general Danish population is 33%; among the elderly, it is 80%. “Ours and others’ findings show that vitamin D deficiency is frequent in the general population of countries at high latitudes and even more frequent in kidney disease patients, including kidney transplanted patients,” commented co-investigator Peter Marckmann, MD, also of Copenhagen University Hospital.
“So it is important to identify and correct hypovitaminosis D not only for optimizing bone health, but also to prevent other potential adverse effects of hypovitaminosis D such as increased risks of cardiovascular disease, certain cancers, and immunological disorders.”