Bone loss in untreated longstanding sarcoidosis

Area of Science:

• Bone Metabolism and Endocrinology
• Rheumatology and Immunology
• Medical Imaging and Diagnostics

Background:

• Previous studies using Quantitative Computed Tomography (QCT) suggested increased bone mineral loss in prednisone-treated sarcoidosis patients.
• The role of sarcoidosis itself in affecting bone mineral content (BMC) remained unclear, as QCT's sensitivity might explain prior findings.
• This study aims to elucidate the direct impact of sarcoidosis on BMC.

Purpose of the Study:

• To assess Bone Mineral Content (BMC) in untreated patients with active sarcoidosis using QCT.
• To determine if sarcoidosis itself, independent of prednisone treatment, affects BMC.
• To evaluate Vertebral Cancellous Mineral Content (VCMC) Z scores in a cohort of sarcoidosis patients.

Main Methods:

• Quantitative Computed Tomography (QCT) was employed to measure Vertebral Cancellous Mineral Content (VCMC).
• VCMC was standardized using Z scores to account for age and sex variations.
• A cohort of 36 untreated patients with active, histologically proven sarcoidosis was studied.

Main Results:

• The overall mean VCMC Z score was -0.41 ± 0.30, not significantly different from normal controls (P > 0.05).
• However, 13 out of 36 patients exhibited VCMC below the normal range.
• Five patients with sarcoidosis lasting over two years had VCMC more than two SD below normal, and four had VCMC below the fracture risk threshold.

Conclusions:

• While the average VCMC Z score was not significantly reduced in untreated sarcoidosis patients, a notable proportion showed decreased bone mineral content.
• Longstanding sarcoidosis appears to be associated with more significant reductions in VCMC.
• QCT is a sensitive tool for detecting potential bone mineral loss in sarcoidosis, warranting further investigation into the mechanisms involved.