Differential diagnosis of vitamin D-related hypercalcemia using serum vitamin D metabolite profiling.

Genetic causes of vitamin D-related hypercalcemia are known to involve mutation of 25-hydroxyvitamin D-24-hydroxylase CYP24A1 or the sodium phosphate co-transporter SLC34A1, which result in excessive 1,25-(OH)2 D hormonal action. However, at least 20% of idiopathic hypercalcemia (IH) cases remain unresolved. In this case-control study, we used precision vitamin D metabolite profiling based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) of an expanded range of vitamin D metabolites to screen German and French cohorts of hypercalcemia patients, to identify patients with altered vitamin D metabolism where involvement of CYP24A1 or SLC34A1 mutation had been ruled out and who possessed normal 25-OH-D3 :24,25-(OH)2 D3 ratios. Profiles were compared to those of hypercalcemia patients with hypervitaminosis D, Williams-Beuren syndrome (WBS), CYP24A1 mutation, and normal subjects with a range of 25-OH-D levels. We observed that certain IH and WBS patients exhibited a unique profile comprising eightfold to 10-fold higher serum 23,25,26-(OH)3 D3 and 25-OH-D3 -26,23-lactone than normals, as well as very low serum 1,25-(OH)2 D3 (2-5 pg/ml) and elevated 1,24,25-(OH)3 D3 , which we interpret implies hypersensitive expression of vitamin D-dependent genes, including CYP24A1, as a general underlying mechanism of hypercalcemia in these patients. Because serum 25-OH-D3 and 24,25-(OH)2 D3 remained normal, we excluded the possibility that the aberrant profile was caused by hypervitaminosis D, but instead points to an underlying genetic cause that parallels the effect of Williams syndrome transcription factor deficiency in WBS. Furthermore, we observed normalization of serum calcium and vitamin D metabolite profiles at follow-up of an IH patient where 25-OH-D was reduced to 9 ng/ml, suggesting that symptomatic IH may depend on vitamin D nutritional status. Other hypercalcemic patients with complex conditions exhibited distinct vitamin D metabolite profiles. Our work points to the importance of serum vitamin D metabolite profiling in the differential diagnosis of vitamin D-related hypercalcemia that can rationalize expensive genetic testing, and assist healthcare providers in selecting appropriate treatment. © 2021 American Society for Bone and Mineral Research (ASBMR).

Vitamin D supplements: The pharmacists' perspective.

OBJECTIVE: The purpose of this narrative review was to provide guidance for pharmacists concerning vitamin D supplementation. METHODS: Relevant studies were identified in a search of MEDLINE/PubMed, EBSCOhost, and Google Scholar from January 1966 to September 2020 using the search terms vitamin D, vitamin D2, vitamin D3, calcitriol, and vitamin D deficiency. Abstracts were reviewed for relevance and, if relevant, full-text articles were retrieved and reviewed. References were checked, and citation searches using identified studies were conducted. The literature search included English-language studies involving administration of vitamin D monotherapy compared with placebo. RESULTS: Serum 25-hydroxyvitamin D levels of less than 12 ng/mL indicate a vitamin D deficiency. The Institute of Medicine recommends a daily intake of 600 IU of vitamin D in individuals aged up to 70 years and 800 IU in those aged above 70 years. Vitamin D is labeled for rickets, osetomalacia, hypophosphatemia (familial or secondary), renal osteodystrophy, and corticosteroid-induced osteoporosis. When used for these indications, vitamin D should be prescribed with appropriate monitoring by a qualified health care practitioner. There is evidence for vitamin D supplementation in individuals aged 75 years or older and in those with problems associated with mobility, gait, or balance. There is insufficient evidence to support vitamin D supplementation in the prevention of cardiovascular disease, cancer, asthma, chronic obstructive pulmonary disease exacerbations, new-onset type 2 diabetes, infectious lung diseases, cognitive dysfunction, Alzheimer disease, and depression, or in prenatal use. CONCLUSION: Pharmacists can provide evidence-based recommendations concerning the indications, dosing, monitoring, and adverse effects of vitamin D supplements.

Prasterone has parallel beneficial effects on the main symptoms of vulvovaginal atrophy: 52-week open-label study.

OBJECTIVE: An objective was to analyze the time course of efficacy of daily intravaginal administration of 0.5% (6.5mg) DHEA (prasterone) for 52 weeks on the moderate to severe (MS) symptoms and signs of vulvovaginal atrophy (VVA). METHOD: Five hundred twenty-one postmenopausal women were enrolled and received daily intravaginal administration of 0.5% DHEA in an open-label phase III study. The severity of the VVA symptoms examined in detail in the different groups. RESULTS: A parallel improvement of pain at sexual activity was observed in women who had moderate to severe (MS) dyspareunia as their most bothersome symptom (MBS) (n=183) or not MBS (n=240) and MS without being MBS (n=57) with a 1.70 severity unit change in the MBS group for a decrease of 66.1% from baseline (p<0.0001 versus baseline) over 52 weeks. A further improvement of dyspareunia, namely 0.33 severity unit (19.4%), was observed with continuing treatment from 12 weeks to 52 weeks. Similar results were observed on vaginal dryness and irritation/itching. Highly significant beneficial effects (p<0.0001 versus baseline for all) were observed at gynecological examination on vaginal secretions, color, epithelial integrity and epithelial surface thickness. CONCLUSION: The present study shows, in addition to the parallel benefits on the three symptoms of VVA, that the choice of any of the MS symptoms as being or not being MBS by women has no influence on the observed therapeutic effect (NCT01256671).

Bone mineral density-affecting genes in Africans.

BACKGROUND: We have recently reported the role of environmental exposure in the ethnic diversity of bone mineral density (BMD). Potential genetic difference has not been adequately assessed. PURPOSE: To determine allele frequencies of BMD-affecting genes and their association with BMD in Africans. METHODS: Allele frequencies at 18 polymorphic sites in 13 genes that affect BMD in Asians and/or Caucasians were determined in 143 recent immigrants (55 men and 88 women, 18-51 years of age) from sub-Saharan Sudan to the United States. Genetic association studies were performed. RESULTS: Among the 14 single-nucleotide polymorphisms (SNPs), 10 were significantly different in allele frequency between Sudanese and Asians, and 10 between Sudanese and Caucasians. Only the osteocalcin gene was not significantly different in allele frequency among Sudanese, Asians and Caucasians. Allele frequencies in the TGFB, COL1A1 and CSR genes were extremely low (<0.04) in the Sudanese. Frequencies of microsatellite alleles in four genes were significantly different among Sudanese, Asians and Caucasians. SNPs in the VDR and ERalpha genes were associated with BMD and/or BMC (bone mineral content) at several bone sites. CONCLUSIONS: Genetic difference may play a role in the ethnic diversity in BMD and/or BMC.

Bone mineral density of recent African immigrants in the United States.

BACKGROUND: Racial/ethnic difference in bone mineral density (BMD) exists. The underlying mechanism is unclear and needs investigation. PURPOSE: To determine BMD and its relation to environmental exposure in recent African immigrants. METHODS: BMD in recent sub-Saharan Sudanese immigrants (55 men and 88 premenopausal women) in the United States was measured. Analysis of covariance (ANCOVA) model was performed, with total body, spine and hip BMD as dependent variables; and sex, age, body weight, the length of stay in the United States, and milk intake as independent variables. RESULTS: BMD Z score in the spine but not total body or hip in the Sudanese immigrants was significantly lower compared with the normative values of African Americans and Caucasians. Total body and hip BMD was positively correlated (p < 0.015) with their length of stay in the United States. Hip BMD was significantly correlated with milk intake (p < 0.02) and marginally (p = 0.052) with their length of stay in the United States, independent of body weight. CONCLUSIONS: Spinal BMD was significantly lower in recent Sudanese immigrants than in African Americans or Caucasians. Their hip and total body BMD was associated with their length of stay in the United States, suggesting a potential environmental factors in the ethnic diversity of BMD.