Vitamin-D status and mineral metabolism in two ethnic populations with sarcoidosis

Giovanna Capolongo, Li Hao Richie Xu, Mariasofia Accardo, Alessandro Sanduzzi, Anna Agnese Stanziola, Annamaria Colao, Carlo Agostini, Miriam Zacchia, Giovambattista Capasso, Beverley Adams-Huet, Orson W. Moe, Naim M. Maalouf, Khashayar Sakhaee, Connie C W Hsia

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8 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)1025-1034
Number of pages10
JournalJournal of Investigative Medicine
Volume64
Issue number5
DOIs
StatePublished - Jan 1 2016

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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    Capolongo, G., Xu, L. H. R., Accardo, M., Sanduzzi, A., Stanziola, A. A., Colao, A., Agostini, C., Zacchia, M., Capasso, G., Adams-Huet, B., Moe, O. W., Maalouf, N. M., Sakhaee, K., & Hsia, C. C. W. (2016). Vitamin-D status and mineral metabolism in two ethnic populations with sarcoidosis. Journal of Investigative Medicine, 64(5), 1025-1034. https://doi.org/10.1136/jim-2016-000101