Factors associated with depression and effects of vitamin d supplementation and maintaining vitamin D sufficiency on depression in patients with knee osteoarthritis
S. Zheng Osteoarthritis and Cartilage VOLUME 26, SUPPLEMENT 1, S308-S309, APRIL 01, 2018
Purpose: To explore risk factors associated with depression and to determine the effects of vitamin D supplementation and maintaining vitamin D sufficiency on depression in patients with knee osteoarthritis (OA).
Methods: Participants with symptomatic knee OA and vitamin D deficiency were enrolled in a randomized, placebo-controlled trial and received 50,000 IU vitamin D3 (N = 209) or placebo (N = 204) monthly for 24 months. Serum 25-hydroxyvitamin D [25(OH)D] was measured at baseline, month 3 and 24. Depression was measured using the patient health questionnaire (PHQ-9) and knee symptoms were assessed using Western Ontario and McMaster Universities Arthritis Index (WOMAC) at baseline, month 3, 6, 12 and 24. Knee structures including cartilage volume, cartilage defects and bone marrow lesions were assessed at baseline and month 24 using MRI. Participants were classified into two groups according to serum 25(OH)D levels at month 3 and 24: 1) not consistently sufficient [25(OH)D≤50 nmol/l at either month 3 or 24], and 2) consistently sufficient [25(OH)D>50 nmol/l at both month 3 and 24].
Results: Over 24 months, 340 participants (82.3% retention rate) completed the study. The prevalence and incidence of depression were 25.4% and 11.2%, respectively. Being female and having a higher WOMAC pain and function were significantly associated with incident depression over 24 months. Depression scores improved in the vitamin D supplementation group compared to the placebo group (β: −0.66, 95% CI: −1.22 to −0.11) and in the consistently vitamin D sufficient group compared to the not consistently sufficient group (β: −0.83, 95% CI: −1.56 to −0.11) over 24 months.
Conclusions: Female sex, knee pain and limited physical function predict the development of depression in knee OA patients. Furthermore, vitamin D supplementation and maintaining sufficient vitamin D levels over 24 months may be beneficial for depression in patients with knee OA.