Vitamin D status in primary hyperparathyroidism: effect of genetic background

Abstract

Primary hyperparathyroidism (PHPT) is associated with hypovitaminosis D as assessed by serum total 25-hydroxyvitamin D (TotalD) levels. The aim of this study is to evaluate whether this is also the case for the calculated bioavailable 25-hydroxyvitamin D (BioD) or free 25-hydroxyvitamin D (FreeD), and whether the vitamin D status is influenced by genetic background. We compared vitamin D status of 88 PHPT patients each with a matched healthy family member sharing genetic background, i.e., first-degree relative (FDR), or not, namely an in-law relative (ILR). We compared TotalD and vitamin D-binding protein (DBP), using the latter to calculate BioD and FreeD. We also genotyped two common DBP polymorphisms (rs7041 and rs4588) likely to affect the affinity for and levels of vitamin D metabolites. TotalD was lower (p < 0.001) in PHPT (12.3 ± 6.6 ng/mL) than either family member group (FDR: 19.4 ± 12.1 and ILR: 23.2 ± 14.1), whether adjusted for DBP or not. DBP levels were also significantly lower (p < 0.001) in PHPT (323 ± 73 mg/L) versus FDR (377 ± 98) or ILR (382 ± 101). The differences between PHPT and control groups for TotalD, BioD, and FreeD were maintained after adjustment for season, gender, and serum creatinine. 25-hydroxyvitamin D, evaluated as total, free, or bioavailable fractions, is decreased in PHPT. No difference was seen between first-degree relative and in-law controls, suggesting that neither genetic nor non-genetic background greatly influences the genesis of the hypovitaminosis D seen in PHPT.

Vitamin D and primary hyperparathyroidism: more insights into a complex relationship

“…11 and Viccia et al 12 report on vitamin D in PHPT and add to our knowledge regarding the pathophysiology of hypovitaminosis D and its role in disease presentation. Battista et al .…”

“…11 and Viccia e t al . 12 add to our understanding of the pathophysiology and effects of hypovitaminosis D in PHPT.…”

“…Battista et al . assessed whether calculated free and bioavailable (free plus albumin-bound) 25OHD levels are low in PHPT and whether vitamin D status is influenced by genetic background 11 . They compared 88 patients with PHPT (mean calcium 11.2 mg/dl, PTH 247 pg/ml, 25OHD 12.3 ng/ml) to matched related and to unrelated family members without PHPT.…”

Calcifediol Rather Than Cholecalciferol for a Patient Submitted to Malabsortive Bariatric Surgery: A Case Report

“…Serum concentration of vitamin D binding protein (DBP), measured using a turbidimetric method [Dako, Denmark; adapted to Roche ModularP (Roche Diagnostics)] in a serum sample collected at this time, was 403 mg/L, a value slightly above the mean of the normal reference population [ 3 ].…”

Low 25‐Hydroxyvitamin D in Primary Hyperparathyroidism: Enhanced Conversion Into 1,25‐Hydroxyvitamin D May Not Be “True” Deficiency

“…S ubnormal serum 25OHD concentrations are reported to occur frequently in individuals with primary hyperparathyroidism (PHP) and are attributed to concurrent vitamin D deficiency. (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) It is plausible that the prevalence of vitamin D deficiency is overestimated and exaggerated because low serum 25OHD levels may be explained by its enhanced conversion into 1,25-hydroxyvitamin D [1,25(OH)…”