Correlation of dietary protein intake with body composition and physical status in patients with knee osteoarthritis

Background and Objectives: Little is known about the association between dietary protein intake and clinical manifestations in osteoarthritis (OA) patients. We aimed to determine the correlation between dietary protein intake and pain severity, functional status, and body composition indices in patients with knee OA. Materials and Methods: This cross-sectional study was performed on 220 OA patients, staged I to Ⅲon Kellgren and Lawrence scale. Patients were selected randomly via cluster sampling method from the health centers of Tabriz between October 2017 and October 2018. Participants' protein intakes were estimated using a semi-quantitative food frequency questionnaire. Western Ontario and McMaster Index (WOMAC) was used to measure the functional status. We used the Visual Analogue Scale for measuring pain severity. The patients’ body composition was measured by a bioelectric impedance device. Results: Total dietary protein intake was 55.36±24.14 grams per day. Higher dietary total and animal-based protein intakes were associated with lower pain severity. There were reverse correlations between dietary total and animal-based protein intakes with the physical disability according to WOMAC total, WOMAC pain, and WOMAC stiffness scores in the subset of patients who didn’t meet the 75 percent of recommended dietary allowance. In these patients, higher total, plant-based, and animal-based protein intakes correlated with WOMAC functional scores. Higher total and animal-based protein intakes were associated with higher soft lean mass and lean body mass in women. Conclusion: Dietary protein intake needs to improve in knee OA patients, and dietary protein intake might be an intermediation objective in these patients.