{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T13:42:00Z","timestamp":1774273320051,"version":"3.50.1"},"reference-count":18,"publisher":"Oxford University Press (OUP)","issue":"3","license":[{"start":{"date-parts":[[2024,4,18]],"date-time":"2024-04-18T00:00:00Z","timestamp":1713398400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100010659","name":"Erasmus MC","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100010659","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100006400","name":"Alnylam","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100006400","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Clinuvel"},{"DOI":"10.13039\/100013220","name":"Ultragenyx","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100013220","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2024,8,14]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>Patients with erythropoietic protoporphyria experience lifelong painful photosensitivity resulting in a lack of sunlight exposure. Previous studies have shown that 47\u201363% of patients with EPP suffer from vitamin D deficiency and a high prevalence of osteoporosis. An effective treatment for EPP has been available since 2016: the \u03b1-melanocyte stimulating hormone analogue afamelanotide. So far, studies on vitamin D levels in EPP have only investigated patients who have not been treated with afamelanotide.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Objectives<\/jats:title>\n                  <jats:p>To investigate the effects of afamelanotide treatment on vitamin D levels in EPP.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>A multicentre observational cohort study in adults with EPP from the Erasmus Medical Centre, the Netherlands, and the University Hospital D\u00fcsseldorf, Germany, was carried out. Routinely collected vitamin D levels between 2005 and 2021 were used for analysis. Patient exposure to cholecalciferol or afamelanotide was categorized into four treatment groups: untreated, cholecalciferol, afamelanotide and combined treatment. A linear mixed model for longitudinal data was applied to measure the effect of the treatment groups compared with the untreated groups on vitamin D levels.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>A total of 230 patients and 1774 vitamin D measurements were included. The prevalence of vitamin D deficiency and severe deficiency remained high despite afamelanotide treatment (&amp;lt; 50\u2005nmol L\u20131 in 71.8% of patients and &amp;lt; 30\u2005nmol L\u20131 in 48.1%, respectively). Afamelanotide treatment alone did not lead to a significant average increase in vitamin D levels [\u03b2 = 0.5, 95% confidence interval (CI) \u20133.2 to 4.2]. In contrast, cholecalciferol and combined therapy with afamelanotide led to a significant increase in vitamin D levels [\u03b2 = 11.6 (95% CI 7.2\u201315.9) and \u03b2 = 15.2 (95% CI 12.3\u201318.1), respectively].<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>Cholecalciferol remains essential for the treatment of vitamin D deficiency in EPP, irrespective of new treatment options like afamelanotide. Afamelanotide treatment did not affect vitamin D levels. We suggest that future guidelines include continuous monitoring of vitamin D and a prescription for cholecalciferol in all patients with EPP, including those treated with afamelanotide.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/bjd\/ljae148","type":"journal-article","created":{"date-parts":[[2024,4,18]],"date-time":"2024-04-18T14:05:04Z","timestamp":1713449104000},"page":"357-364","source":"Crossref","is-referenced-by-count":4,"title":["The effects of cholecalciferol and afamelanotide on vitamin D levels in erythropoietic protoporphyria: a\u00a0multicentre cohort study"],"prefix":"10.1093","volume":"191","author":[{"given":"Louisa G","family":"Kluijver","sequence":"first","affiliation":[{"name":"Porphyria Centre Rotterdam, Centre for Lysosomal and Metabolic Disease, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Centre , Rotterdam , the Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mitra","family":"Nekouei Shahraki","sequence":"additional","affiliation":[{"name":"Porphyria Centre Rotterdam, Centre for Lysosomal and Metabolic Disease, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Centre , Rotterdam , the Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Margreet A E M","family":"Wagenmakers","sequence":"additional","affiliation":[{"name":"Porphyria Centre Rotterdam, Centre for Lysosomal and Metabolic Disease, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Centre , Rotterdam , the Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bettina E","family":"Hanssen","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, Biostatistics, Erasmus MC, University Medical Centre , Rotterdam , the Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Viola","family":"Kuerten","sequence":"additional","affiliation":[{"name":"Department of Dermatology, University Hospital D\u00fcsseldorf, Medical Faculty, Heinrich-Heine-University , D\u00fcsseldorf , Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kathrin","family":"Schelonke","sequence":"additional","affiliation":[{"name":"Department of Dermatology, University Hospital D\u00fcsseldorf, Medical Faculty, Heinrich-Heine-University , D\u00fcsseldorf , Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bernhard","family":"Homey","sequence":"additional","affiliation":[{"name":"Department of Dermatology, University Hospital D\u00fcsseldorf, Medical Faculty, Heinrich-Heine-University , D\u00fcsseldorf , Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Janneke G","family":"Langendonk","sequence":"additional","affiliation":[{"name":"Porphyria Centre Rotterdam, Centre for Lysosomal and Metabolic Disease, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Centre , Rotterdam , the 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