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Study · Observational study · 2025

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The Impact of Minimal Sunlight Exposure on Bone Health: Insights From a Cohort Study in Erythropoietic Protoporphyria.

Kluijver LG, Wagenmakers MAEM, Wilson JHP, Langendonk JG

The Journal of clinical endocrinology and metabolism1 May 2025Cited by 3 (Europe PMC)

PMID39401412 (opens in a new tab)PMCIDPMC12086420 (opens in a new tab)DOI10.1210/clinem/dgae729 (opens in a new tab)PepBankPUB-39401412
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Summary

ContextErythropoietic protoporphyria (EPP) is a rare inherited metabolic disease, causing lifelong painful phototoxic reactions, minimal sunlight exposure, and vitamin D deficiency. Previous studies reported a high osteoporosis prevalence in EPP patients.ObjectiveTo identify those at risk for low bone mineral density (BMD) and assess which factors, including treatment with cholecalciferol and afamelanotide, improve BMD in EPP.MethodsA longitudinal ambispective single-center cohort study. Data from patient files and two-time questionnaires from adult patients with EPP who underwent at least one dual-energy x-ray absorptiometry (DXA) scan between 2012 and 2023 were used.ResultsBMD is low in EPP patients, with 82.7% of the 139 patients having a Z-score below 0 SD at baseline. Low BMD classified as osteopenia was found in 39.5%, and osteoporosis in 15.3%. There were 50 osteoporosis-related fractures in 34.2% of patients. Aging (odds ratio [OR] 1.08; CI, 1.03-1.12), persistent vitamin D deficiency (OR 1.11; 95% CI, 1.00-1.23) and a low body mass index (OR 0.91; 95% CI, 0.82-0.99) increased the odds of low BMD. Patients with a vitamin D deficiency (OR 5.51; 95% CI, 1.69-17.92) and no cholecalciferol at baseline (OR 0.22; 95% CI, 0.04-1.34) had the highest odds of improving their BMD. Afamelanotide did not improve BMD.Conclusion25-hydroxyvitamin D (25(OH)D) status plays a crucial role in both preventing low BMD and improving BMD. EPP is a natural model for lack of sunlight exposure and vitamin D deficiency, underlining the importance of lifelong adequate vitamin D status for bone health in the general population.
CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study1

1 result from studies that gave the peptide. 1 result from people.

  1. 01HumanObservational studyEfficacy outcome

    In adults with erythropoietic protoporphyria, afamelanotide treatment did not improve bone mineral density.

    In plain wordsIn adults with EPP, bone density did not improve with afamelanotide.

    Peptide
    Melanotan I (afamelanotide)
    Outcome
    No significant changeBone mineral density change
    Study

    n: not reported in source

    Outcome group
    Bone and joint · Musculoskeletal
    Studied dose
    Dose not stated

    Source sentences

    Summary
    Afamelanotide did not improve BMD.
    1 context sentence
    Summary · context
    A longitudinal ambispective single-center cohort study.

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Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    13 Oct 2026, 21:44 UTC

    Study results updated

  2. Version 1

    13 Oct 2026, 16:31 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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