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

Abstract

Background:Prior studies have linked bone marrow density (BMD) with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). However, the risk of BMD loss and associated factors in relapsing remitting MS (RRMS) and NMOSD patients remains insufficiently evaluated. The objective of this study was to assess the risk of osteopenia and osteoporosis and identify associated factors in RRMS and NMOSD.Methods:This matched case-control study was conducted in Isfahan, Iran, between November 2022 and November 2023. Patients diagnosed with RRMS and NMOSD, along with healthy controls (HCs), underwent densitometry of the femoral neck and lumbar spine regions. Osteopenia and osteoporosis were defined according to the WHO criteria, and associated risk factors were identified through logistic and linear regression analyses.Results:The 30 RRMS and 30 NMOSD patients, as well as 35 age- and sex-matched healthy controls (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 D3) (OR = 0.9, P = 0.034), and phosphorus levels (OR = 0, P = 0.004).Conclusions:Although no association was found between RRMS and BMD loss, NMOSD increased the risk of BMD loss threefold compared with HCs. Clinicians are advised to routinely evaluate these patients and their risk factors for BMD loss and implement preventive measures accordingly.