Article Text

other Versions

PDF
Vitamin-D status and mineral metabolism in two ethnic populations with sarcoidosis
  1. Giovanna Capolongo1,2,3,
  2. Li Hao Richie Xu2,
  3. Mariasofia Accardo4,
  4. Alessandro Sanduzzi4,
  5. Anna Agnese Stanziola4,
  6. Annamaria Colao5,
  7. Carlo Agostini6,
  8. Miriam Zacchia3,
  9. Giovambattista Capasso3,
  10. Beverley Adams-Huet7,
  11. Orson W Moe1,2,
  12. Naim M Maalouf1,2,
  13. Khashayar Sakhaee1,2,
  14. Connie C W Hsia1
  1. 1Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
  2. 2Charles & Jane Pak Center for Mineral Metabolism & Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
  3. 3Department of Cardio-thoracic & Respiratory Sciences, Division of Nephrology, Second University of Naples, Naples, Italy
  4. 4Department of Clinical Medicine & Surgery, Division of Respiratory disease, University Federico II of Naples, Naples, Italy
  5. 5Department of Clinical Medicine & Surgery, Unit of Endocrinology, University Federico II of Naples, Naples, Italy
  6. 6Department of Medicine (DIMED), Clinical Immunology Unit, Padua University, Italy
  7. 7Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
  1. Correspondence to Dr Connie CW Hsia, Department of Internal Medicine, Pulmonary and Critical Care, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9034, USA; connie.hsia{at}utsouthwestern.edu

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 (Ca2+) 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 Ca2+ 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.

  • Sarcoidosis
  • Vitamin D
  • Kidney Calculi

Statistics from Altmetric.com

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.