Objective: Osteoporosis is common in patients with multiple sclerosis (MS) with long-standing disease. Hypovitaminosis D is a candidate risk factor for MS, and vitamin D also mediates bone mineralization. If vitamin D exerts a major effect on MS risk, skeletal consequences of hypovitaminosis D could be apparent shortly after the onset of MS. In order to test this hypothesis, we assessed bone mineral density (BMD) at early stages of disease in patients with no or minor disability.
Methods: A population-based case-control study was conducted on 99 consecutive and newly diagnosed patients with clinically isolated syndrome or MS, and on 159 age-, sex-, and ethnicity-matched controls. BMD was measured by dual-energy x-ray absorptiometry of the femoral neck, total hip, anterior-posterior lumbar spine, total body, and nondominant ultradistal radius.
Results: A total of 50.5% of the patients exhibited either osteopenia (-2.5 < T score < -1.0) or osteoporosis (T score ≤-2.5) in at least one skeletal site, compared to 37.1% of controls (p = 0.034). After adjusting for possible confounders, left femoral total hip T score and lumbar spine BMD and T score were significantly lower in patients than in controls (p = 0.023, 0.039, and 0.026, respectively).
Conclusions: Low bone mass appears to occur early in MS. This is compatible with shared etiologic or pathogenic factors in MS and osteoporosis, and calls for an active approach to optimize bone health in early stages of MS.