Background Vitamin D deficiency can be associated with muscle weakness and is common in elderly people.
Objectives The aim of this study was to evaluate the effects of the vitamin D levels on pain intensity, muscle strength and functional status of the elderly patients with knee osteoarthritis (OA).
Methods Eighty-one patients with knee OA aged between 65 and 71 years were included in the study. Gender, ages and Body Mass Indexes (BMI) were recorded. The radiographic degree of knee OA was graded as 1 to 3 according to Kellgren and Lawrence scale. Visual Analog Scale (VAS) was used to measure pain intensity and Turkish version of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to evaluation of functional status. Measurements of isokinetic muscular function of both flexor and extensor muscles and peak torque/body weight levels were performed at the angular velocities of 60°/sec and 180°/sec using a Biodex system pro4. Serum calcium, phosphate, alkaline phosphatase, albumin, intact parathyroid hormone (iPTH), complete blood count, liver and kidney function tests, thyroid function tests and 25(OH) vitamin D levels were studied. Patients were divided into 2 subgroups according to 25(OH) vitamin D levels: Group 1 consisted of 40 patients with serum 25(OH) vitamin D levels below 20 ng/ml while 41 patients with serum 25(OH) vitamin D levels equal to 20 ng/ml and above were included in Group 2.
Results The whole study group consisted of 41 women and 40 men (81 patients). The mean age of the group 1 patients (20 women, 20 men) was 68,1±1,48 years, and the mean age of the group group 2 patients (21 women, 20 men) was 67,8±1,30 years (p>0.05). The mean vitamin D level were 10,98±4,68 ng/ml in group 1 and 42,99±17,13 ng/ml in group 2. The mean VAS values of group 1 at rest and motion were significantly higher than those of group 2 (p=0,014, p=0,018, respectively). The mean values of pain, function and total scores of the WOMAC were significantly higher in group 1 than group 2 patients (p=0,001, p=0,0001, p=0,0001, respectively). At the angular velocities of 60°/sec and 180°/sec, significantly lower values were observed in both flexor and extensor peak torque and peak torque/body weight in group 1 patients (p<0,05).
Conclusions Vitamin D deficiency can be a contributor factor in pain, disability and muscle weakness in patients with knee osteoarthritis. Concomitant vitamin D deficiency should be considered in elderly patients with knee osteoarthritis.
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Disclosure of Interest : None declared
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