Correlation between Abdominal Obesity and Pain in Knee Osteoarthritis

Objective: Obesity is an independent risk factor for the occurrence of knee osteoarthritis. The influence of abdominal obesity is not well studied. We proposed to determine the relationship between total abdominal obesity, pain, and functional impairment with the severity of radiographic changes in knee osteoarthritis. Methods: A cross-sectional study including 92 patients with knee pain was performed. The evaluation of degree of pain in the knee was assessed by the visual analogue scale and the functional impairment by WOMAC and Lequesne indices. Radiographic severity was assessed by Kellgren and Lawrence score (KL score). Results: Mean age of patients was 55.2 years (19-86), with a predominance of women (80.4% of patients). Mean body mass index (BMI) was 30.66 kg/m2 (18.5-49.97). Obesity was found in 53 patients (57.6%). The average waist circumference (WC) was 102.82 (± 15.51) centimeters. Abdominal obesity was found in 80 patients (87%). Patients had a mean visual analogue scale (VAS) of 18 ± 23.24 mm. The average algofunctionnal Lequesne score was 8.95 (0-23), and the WOMAC score was 26.82 (0-69). Fifty percent of patients had stage 3 of OA according to KL score. We found no association between BMI and intensity of knee pain (p = 0.278), but WC was significantly associated with the elevation of VAS (p = 0.008). Physical function was positively correlated with BMI and WC (p = 0.001). Finally, BMI and WC were significantly associated with radiographic severity (grade 1-2 of KL vs. grade 3-4 of KL) (respectively, p = 0.001; p = 0.017). Conclusion: Both obesity and abdominal obesity are independently associated with pain, disability, and radiographic severity of knee osteoarthritis.