Bone Mineral Density Loss in Relapsing-remitting Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder: A Matched Case-control Study (PP-25)

Given prior research, the risk of bone mineral density (BMD) loss and associated factors in relapsing-remitting MS (RRMS) and neuromyelitis optica spectrum disorder (NMOSD) patients have been insufficiently evaluated. This study aimed to assess the risk of osteopenia and osteoporosis and identify related factors in patients with RRMS and NMOSD.
Methods
This matched case-control study was conducted in Isfahan, Iran, between November 2022 and November 2023. RRMS and NMOSD patients, along with healthy controls (HCs), underwent densitometry of the femoral neck and lumbar spine regions. Furthermore, demographics and clinical and laboratory data were collected from these patients and HCs. The risk factors were determined through logistic and linear regression analyses.
Results
The 30 RRMS and 30 NMOSD patients and 35 age, sex-matched HCs were included. The odds of osteopenia or osteoporosis did not significantly differ between RRMS patients and HCs (odds ratio (OR) = 1.7, p = 0.34). In contrast, NMOSD patients had a higher probability of developing these conditions than HCs (OR = 3.3, p = 0.02). BMD loss in RRMS was associated significantly with alkaline phosphatase (ALP) levels (OR = 1.1, p = 0.013), while in NMOSD, significant relationships were found with age (OR = 1.3, p = 0.013), EDSS (OR = 3.4, p = 0.02), physical activity (OR = 0.2, p = 0.02), ALP (OR = 1.2, p = 0.02), 25-hydroxy Vitamin D (Vitamin D) (OR = 0.9, p = 0.034), and phosphorus levels (OR = 0.1, p = 0.004).
Conclusion
Although no association was found between RRMS and BMD loss, NMOSD increased the risk of BMD loss threefold compared with HCs. Additionally, while ALP was a risk factor for BMD loss in MS patients, age, disability, physical activity, ALP, and Vitamin D3 were independent predictors of BMD loss in NMOSD patients.