Vitamin D and primary hyperparathyroidism (PHPT).
Vitamin D deficiency and PHPT are two common conditions, especially in postmenopausal women. Vitamin D deficiency is said to be even more frequent in PHPT patients than in the general population due to an accelerated conversion of 25OHD into calcitriol or 24-hydroxylated compounds. Although several studies have reported worsening of PHPT phenotype (larger tumours, higher PTH levels, more severe bone disease) when vitamin D deficiency coexists whereas vitamin D supplementation in PHPT patients with a serum calcium level<3 mmol/L has been shown to be safe (no increase in serum or urinary calcium) and to decrease serum PTH concentration, that many physicians are afraid to give vitamin D to already hypercalcemic PHPT patients. On the other hand, it is possible that, in some patients, a persistent vitamin D deficiency induces, in the long-term, an autonomous secretion of PTH (i.e. tertiary hyperparathyroidism). The mechanism by which this could occur is unclear however. Finally, as many, otherwise normal, subjects with vitamin D insufficiency may have an increased serum PTH level we believe that those with vitamin D insufficiency should be excluded from a reference population for serum PTH levels. By doing that, we found that the upper normal limit for serum PTH was 25-30% lower than in the whole population.
Souberbielle
Jean-Claude
JC
Service d'Explorations Fonctionnelles, Hôpital Necker-Enfants Malades, and Faculté de Médecine, Centre de Recherche Croissance et Signalisation (INSERM U845), Université Paris Descartes, France. jean-claude.souberbielle@nck.aphp.fr
Maury
Emilie
E
Friedlander
Gérard
G
Cormier
Catherine
C
D000368:Aged; D001842:Bone and Bones / Q000378:metabolism; D002117:Calcitriol / Q000378:metabolism; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood; D049950:Hyperparathyroidism, Primary / Q000097:blood* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D012016:Reference Values; D014807:Vitamin D / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000378:metabolism
D014807:Vitamin D; D002117:Calcitriol