Vitamin-D Status and Mineral Metabolism in Two Ethnic Populations with Sarcoidosis. Issue 5 (April 2016)

• Record Type: Journal Article
• Authors: Capolongo, Giovanna; Xu, Li Hao Richie; Accardo, Mariasofia; Sanduzzi, Alessandro; Stanziola, Anna Agnese; Colao, Annamaria; Agostini, Carlo; Zacchia, Miriam; Capasso, Giovambattista; Adams-Huet, Beverley; Moe, Orson W; Maalouf, Naim M; Sakhaee, Khashayar; Hsia, Connie C W
• Is Part Of: Journal of investigative medicine. Volume 64:Issue 5(2016)
• Page Start: 1025
• Page End: 1034
• Publication Date: 2016-04
• Subjects: Clinical medicine -- Periodicals; Medicine -- Research -- Periodicals; Medicine; Research -- United States; Clinical medicine; Medicine -- Research; Periodicals; 616.075
• DOI: 10.1136/jim-2016-000101
• Languages: English
• ISSNs: 1081-5589

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)2 D) 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)2 D, 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.