Vitamin D deficiency, functional status, and balance in older adults with osteoarthritis

BACKGROUND: Low vitamin D levels are associated with a more severe case of knee osteoarthritis (OA). However, there are few published reports concerning an association between vitamin D deficiency and functional status of individuals with OA and no reports about postural balance in this population. AIM: To analyze the relationship between vitamin D deficiency and severity, functional status, and balance in elderly patients with OA. METHODS: In this cross-sectional study, 105 elderly patients with hip and knee OA were included. The severity was assessed by the Kellgren-Lawrence criteria. The functional status was assessed with the Lequesne index. Postural balance was assessed using a force platform, and center-of-pressure parameters (velocity at anteroposterior and mediolateral axis) were used as the balance outcomes. Serum 25(OH) vitamin D levels were measured using a chemiluminescence method. RESULTS: Most of the patients (mean age: 70.6 ± 6.5 years) were female (n = 78, 74.3%). In the group with vitamin D deficiency, 43 patients (56.6%) had severe OA, while 33 patients (43.4%) had mild or moderate OA (χ(2) test, P = 0.04). Patients with vitamin D deficiency showed a higher Lequesne index score (Mann-Whitney test, P = 0.04), indicating a worse functional impairment when compared to individuals with normal vitamin D levels. Additionally, patients with vitamin D deficiency had worse postural balance according to the Mann-Whitney test (P = 0.03). CONCLUSION: Vitamin D deficiency is associated with worse severity, functional status, and postural balance in patients with OA.