Hypovitaminosis D in patients undergoing kidney transplant: the importance of sunlight exposure

Abstract

OBJECTIVES:Recent studies have shown a high prevalence of hypovitaminosis D, defined as a serum 25-hydroxyvitamin D level less than 30 ng/ml, in both healthy populations and patients with chronic kidney disease. Patients undergoing kidney transplant are at an increased risk of skin cancer and are advised to avoid sunlight exposure. Therefore, these patients might share two major risk factors for hypovitaminosis D: chronic kidney disease and low sunlight exposure. This paper describes the prevalence and clinical characteristics of hypovitaminosis D among patients undergoing kidney transplant.METHODS:We evaluated 25-hydroxyvitamin D serum levels in a representative sample of patients undergoing kidney transplant. We sought to determine the prevalence of hypovitaminosis D, compare these patients with a control group, and identify factors associated with hypovitaminosis D (e.g., sunlight exposure and dietary habits).RESULTS:Hypovitaminosis D was found in 79% of patients undergoing kidney transplant, and the major associated factor was low sunlight exposure. These patients had higher creatinine and intact parathyroid hormone serum levels, with 25-hydroxyvitamin D being inversely correlated with intact parathyroid hormone serum levels. Compared with the control group, patients undergoing kidney transplant presented a higher prevalence of 25-hydroxyvitamin D deficiency and lower serum calcium, phosphate and albumin but higher creatinine and intact parathyroid hormone levels.CONCLUSIONS:Our results confirmed the high prevalence of hypovitaminosis D in patients undergoing kidney transplant. Therapeutic strategies such as moderate sunlight exposure and vitamin D supplementation should be seriously considered for this population.

Reference values of 25-hydroxyvitamin D revisited: a position statement from the Brazilian Society of Endocrinology and Metabolism (SBEM) and the Brazilian Society of Clinical Pathology/Laboratory Medicine (SBPC)

“…Vitamin D deficiency is prevalent among patients with chronic renal disease (CKD) treated conservatively or with dialysis, and among kidney-transplanted patients ( 104 , 105 ). A meta-analysis with more than 17,000 patients concluded that hypovitaminosis D was associated with an increased risk of all-cause mortality, especially in patients undergoing dialysis.…”

Prevalence of Musculoskeletal and Metabolic Disorders in Kidney Transplant Recipients: A Systematic Review and Meta-Analysis

“…The study design was cross-sectional in 27 studies [ 11 , 12 , 14 , 15 , 18 – 21 , 23 – 32 , 34 – 37 , 41 – 45 ] (71.1%) and longitudinal in 11 [ 13 , 16 , 17 , 22 , 33 , 38 – 40 , 46 – 48 ] (28.9%). All these articles were published between 2001 and 2021, and most of them were conducted in Europe [ 13 , 14 , 16 , 19 – 24 , 29 – 31 , 35 , 36 , 38 , 39 , 42 ] (44.7%), although there were also studies from Asia [ 11 , 18 , 25 – 27 , 34 , 37 , 40 , 43 , 45 , 46 , 48 ] (31.6%), America [ 15 , 17 , 28 , 32 , 33 , 44 , 47 ] (18.4%) and Oceania [ 12 , 41 ] (5.3%).…”

“…The overall prevalence was 29.8% (95% CI: 23.8-36.7; I 2 = 96.8) (Supplementary Figure S13). (e) Hypovitaminosis D: Eight studies [14,19,31,37,[42][43][44][45] analysed the prevalence of this disorder. In this population of 2,495 people, the overall prevalence was 81.8% (95% CI: 67.…”

“…Hypovitaminosis D is associated with immunosuppressive therapy, residual renal function after transplantation, malabsorption, poor diet or reduced exposure to sunlight [ 62 , 64 ]. The vitamin D status of the body is tested by blood levels of calcidiol, a precursor of this vitamin; hypovitaminosis D is therefore understood to be a blood level of calcidiol of less than 30 ng/mL, with vitamin D insufficiency being between 15 and 30 ng/mL and vitamin D deficiency being less than 15 ng/mL [ 44 , 68 ]. According to the article published by Evenepoel et al, [ 68 ] the prevalence of hypovitaminosis D in the third month after renal transplantation is 78%, and according to the articles by Bouquegneau et al [ 9 ] and Alshayeb et al, [ 64 ] vitamin D deficiency would be present in 30% of the operated patients.…”