Vitamin D Aids Bones in Erythropoietic Protoporphyria

TOPLINE:

Patients with erythropoietic protoporphyria (EPP) have a higher prevalence of low bone mineral density (BMD) than the general healthy population, but BMD improves with cholecalciferol supplementation.

METHODOLOGY:

• Previous studies have reported a high prevalence of osteoporosis in patients with EPP, likely due to a deficiency in vitamin D resulting from limited sunlight exposure.
• This longitudinal cohort study aimed to identify risk factors for low BMD in patients with EPP and assess factors associated with BMD improvement.
• Researchers identified adult patients with EPP who visited the Erasmus Medical Center in Rotterdam, the Netherlands, and underwent at least one dual-energy x-ray absorptiometry scan.
• Data on BMD, vitamin D levels, and history of fractures were collected retrospectively from the medical records.
• The main outcome was BMD as assessed at the femoral neck and lumbar spine and reported as T-scores and Z-scores, which compare patient scores with scores of healthy young adults and age-matched adults, respectively.
• Furthermore, the effects of cholecalciferol supplementation and afamelanotide treatment on BMD were evaluated.

TAKEAWAY:

• Researchers included 139 patients with EPP (mean age, 39.5 years; 49.6% women).
• Low BMD was prevalent in patients with EPP, with 82.7% having a Z-score
• Aging was associated with an 8% increase in the risk for osteoporosis (P P = .04) and decreased by 9% with a higher body mass index (P = .04).
• The odds of an increase in BMD were higher in women (odds ratio [OR], 3.73; P = .01), whereas the odds of a decrease in BMD were higher in individuals with a higher body mass index (OR, 1.20; P = .02) and vitamin D deficiency (OR, 2.77; P = .03).
• Cholecalciferol supplementation improved BMD in patients with vitamin D deficiency (OR, 0.22; P = .03), whereas afamelanotide treatment did not.

IN PRACTICE:

“Our findings establish the high prevalence of osteoporosis and fractures in EPP at relatively young age, emphasizing the importance of adequately addressing vitamin D deficiency for both osteoporosis prevention and BMD improvement,” the authors wrote. “We suggest that future guidelines on the treatment of EPP include continuous 25(OH)D [25-hydroxyvitamin D] monitoring, supplementation, and a one-time DEXA-scan for all adult EPP patients,” they added.

SOURCE:

This study was led by Louisa G. Kluijver, MD, Porphyria Center Rotterdam, Center for Lysosomal and Metabolic Disease, Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands. It was published online in The Journal of Clinical Endocrinology & Metabolism.

LIMITATIONS: 

This study had a small sample size, which may have limited prediction modeling. The vitamin D deficiency score did not consider the duration or severity of the deficiency. Most vitamin D measurements were taken during spring, summer, and autumn, which may have led to overestimation of the deficiency score.

DISCLOSURES:

No grants or fellowships were received to support the writing for the study. One author disclosed participation in industry-sponsored trials funded by Moderna and Ultragenyx. Another disclosed participation in industry-sponsored trials funded by Ultragenyx, Clinuvel, and Alnylam.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.