Grahame J Elder1. 1. Centre for Transplant and Renal Research, Westmead Millennium Institute, Sydney, New South Wales, Australia. g.elder@garvan.unsw.edu.au
Abstract
AIM: Many patients with chronic kidney disease (CKD) have reduced levels of 25-hydroxyvitamin D (25(OH)D). Although renal conversion of 25(OH)D to calcitriol is reduced or absent in CKD stage 5 (GFR < 15 mL/min per 1.73 m(2) or on dialysis), 25(OH)D may have direct skeletal and non-skeletal paracrine actions. The aim of this study was to assess seasonal variation in levels of 25(OH)D, bone turnover markers and bone mineral density, which would support a direct physiological role for 25(OH)D. METHODS: Vitamin D levels, bone turnover markers and bone mineral density were measured and assessed for seasonal variation in 257 patients about to undergo kidney or kidney pancreas transplantation. RESULTS: The mean age was 43 +/- 11 years; 62% were on haemodialysis, 24% on peritoneal dialysis and 34% had type 1 diabetes. Serum 25(OH)D was less than 50 nmol/L in 39% and lower levels were associated with female sex, diabetes and peritoneal dialysis (P < 0.0001 for each). Levels of 25(OH)D varied by season (P = 0.018; anova) peaking in autumn with a nadir in spring and calcitriol levels followed a similar seasonal trend. Bone mineral denisty Z-scores differed between summer and winter at the lumbar spine (P = 0.009) with a similar trend at the hip. Osteocalcin levels also showed seasonal periodicity (P = 0.0142) and together with alkaline phosphatase were higher in summer than winter. CONCLUSION: In summary, these data suggest direct effects of 25(OH)D on bone parameters in CKD stage 5 and support the need for prospective studies to establish the effect of treatments that increase 25(OH)D levels in all stages of CKD.
AIM: Many patients with chronic kidney disease (CKD) have reduced levels of 25-hydroxyvitamin D (25(OH)D). Although renal conversion of 25(OH)D to calcitriol is reduced or absent in CKD stage 5 (GFR < 15 mL/min per 1.73 m(2) or on dialysis), 25(OH)D may have direct skeletal and non-skeletal paracrine actions. The aim of this study was to assess seasonal variation in levels of 25(OH)D, bone turnover markers and bone mineral density, which would support a direct physiological role for 25(OH)D. METHODS:Vitamin D levels, bone turnover markers and bone mineral density were measured and assessed for seasonal variation in 257 patients about to undergo kidney or kidney pancreas transplantation. RESULTS: The mean age was 43 +/- 11 years; 62% were on haemodialysis, 24% on peritoneal dialysis and 34% had type 1 diabetes. Serum 25(OH)D was less than 50 nmol/L in 39% and lower levels were associated with female sex, diabetes and peritoneal dialysis (P < 0.0001 for each). Levels of 25(OH)D varied by season (P = 0.018; anova) peaking in autumn with a nadir in spring and calcitriol levels followed a similar seasonal trend. Bone mineral denisty Z-scores differed between summer and winter at the lumbar spine (P = 0.009) with a similar trend at the hip. Osteocalcin levels also showed seasonal periodicity (P = 0.0142) and together with alkaline phosphatase were higher in summer than winter. CONCLUSION: In summary, these data suggest direct effects of 25(OH)D on bone parameters in CKD stage 5 and support the need for prospective studies to establish the effect of treatments that increase 25(OH)D levels in all stages of CKD.
Authors: Heidi J Kalkwarf; Michelle R Denburg; C Frederic Strife; Babette S Zemel; Debbie L Foerster; Rachel J Wetzsteon; Mary B Leonard Journal: Kidney Int Date: 2011-12-28 Impact factor: 10.612
Authors: Luigi Francesco Morrone; Pergiorgio Bolasco; Corrado Camerini; Giuseppe Cianciolo; Adamasco Cupisti; Andrea Galassi; Sandro Mazzaferro; Domenico Russo; Luigi Russo; Mario Cozzolino Journal: J Nephrol Date: 2016-04-09 Impact factor: 3.902