title: Vitamin-D status and mineral metabolism in two ethnic populations with sarcoidosis.
abstract: Vitamin-D insufficiency and sarcoidosis are more common and severe in African Americans (AA) than Caucasians. In sarcoidosis, substrate-dependent extrarenal 1,25-dihydroxyvitamin-D (1,25-(OH)2D) production is thought to contribute to hypercalciuria and hypercalcemia, and vitamin-D repletion is often avoided. However, the anti-inflammatory properties of vitamin-D may also be beneficial. We prospectively examined serum vitamin-D levels, calcium balance, and the effects of vitamin-D repletion in 86 AA and Caucasian patients with biopsy-proven active sarcoidosis from the USA (US) and Italy (IT) in university-affiliated outpatient clinics. Clinical features, pulmonary function, and calciotropic hormones were measured. 16 patients with vitamin-D deficiency and normal serum ionized calcium (Ca(2+)) were treated with oral ergocalciferol (50,000 IU/week) for 12 weeks. Baseline mineral parameters were similar in US (93% AA) and IT (95% Caucasian) patients irrespective of glucocorticoid treatment. Pulmonary dysfunction was less pronounced in IT patients. Nephrolithiasis (in 11% US, 17% IT patients) was associated with higher urinary calcium excretion. Vitamin-D deficiency was not more prevalent in patients compared to the respective general populations. As serum 25-hydroxyvitamin-D (25-OHD) rose postrepletion, serum 1,25-(OH)2D, γ-globulins, and the previously elevated angiotensin converting enzyme (ACE) levels declined. Asymptomatic reversible increases in Ca(2+) or urinary calcium/creatinine (Ca/Cr) developed in three patients during repletion. In conclusion, Caucasian and AA patients show similar calcium and vitamin D profiles. The higher prevalence of hypercalciuria and nephrolithiasis in sarcoidosis is unrelated to endogenous vitamin-D levels. Vitamin-D repletion in sarcoidosis is generally safe, although calcium balance should be monitored. A hypothesis that 25-OHD repletion suppresses granulomatous immune activity is provided.
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA Charles & Jane Pak Center for Mineral Metabolism & Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA Department of Cardio-thoracic & Respiratory Sciences, Division of Nephrology, Second University of Naples, Naples, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Capolongo
authors.affiliation: Charles & Jane Pak Center for Mineral Metabolism & Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Li Hao Richie
authors.initials: LH
authors.lastname: Xu
authors.affiliation: Department of Clinical Medicine & Surgery, Division of Respiratory disease, University Federico II of Naples, Naples, Italy.
authors.forename: Mariasofia
authors.initials: M
authors.lastname: Accardo
authors.affiliation: Department of Clinical Medicine & Surgery, Division of Respiratory disease, University Federico II of Naples, Naples, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sanduzzi
authors.affiliation: Department of Clinical Medicine & Surgery, Division of Respiratory disease, University Federico II of Naples, Naples, Italy.
authors.forename: Anna Agnese
authors.initials: AA
authors.lastname: Stanziola
authors.affiliation: Department of Clinical Medicine & Surgery, Unit of Endocrinology, University Federico II of Naples, Naples, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Colao
authors.affiliation: Department of Medicine (DIMED), Clinical Immunology Unit, Padua University, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Agostini
authors.affiliation: Department of Cardio-thoracic & Respiratory Sciences, Division of Nephrology, Second University of Naples, Naples, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Zacchia
authors.affiliation: Department of Cardio-thoracic & Respiratory Sciences, Division of Nephrology, Second University of Naples, Naples, Italy.
authors.forename: Giovambattista
authors.initials: G
authors.lastname: Capasso
authors.affiliation: Charles & Jane Pak Center for Mineral Metabolism & Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Beverley
authors.initials: B
authors.lastname: Adams-Huet
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA Charles & Jane Pak Center for Mineral Metabolism & Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Orson W
authors.initials: OW
authors.lastname: Moe
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA Charles & Jane Pak Center for Mineral Metabolism & Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Naim M
authors.initials: NM
authors.lastname: Maalouf
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA Charles & Jane Pak Center for Mineral Metabolism & Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Khashayar
authors.initials: K
authors.lastname: Sakhaee
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Connie C W
authors.initials: CC
authors.lastname: Hsia
mesh_terms: D002118:Calcium / Q000652:urine; D016022:Case-Control Studies; D003710:Demography; D005006:Ethnicity; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D008903:Minerals / Q000378:metabolism*; D053040:Nephrolithiasis / Q000097:blood / Q000150:complications / Q000503:physiopathology; D012507:Sarcoidosis / Q000097:blood* / Q000188:drug therapy / Q000503:physiopathology / Q000652:urine; D014481:United States; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D005938:Glucocorticoids; D008903:Minerals; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium
keywords: Kidney Calculi; Sarcoidosis; Vitamin D