Chronic knee osteoarthritis: Relationships of body mass index and selected psychosocial factors among Nigerians.

Background: Knee Osteoarthritis is the most commonly affected joint among Africans. There is a shred of preliminary evidence that a high body mass index (BMI) is associated with high kinesiophobia. Little is known about the relationships of psychosocial factors such as Kinesiophobia, Pain Catastrophizing (PC), Self-Efficacy (SE), and BMI among Nigerians with knee OA.

Objective: This study aims to determine the relationships between BMI and selected psychosocial factors (kinesiophobia, pain catastrophizing, and self-efficacy) among individuals with knee OA in Nigeria.

Methods: Seventy-seven consecutively sampled patients diagnosed with knee OA from three selected public hospitals in Enugu, South-East Nigeria, participated in this cross-sectional survey. Brief Fear of Movement Scale for Osteoarthritis (BFMSO), Pain Catastrophizing Scale (PCS), and Arthritis Self-Efficacy Scale-8 item (ASES-8 item) were used to assess Kinesiophobia, PC, and SE, respectively. Also, a stadiometer and weighing scale were used to determine height and weight respectively. Data were analyzed using Pearson's correlation coefficient at $p<0.05$ and multiple linear regression.

Results: Participants were aged $58.04\pm 12.46$ years. Female participants had a higher BMI ($31.51\pm 6.82$) than the males ($26.86\pm 3.03$). The mean scores for BMI of the right knee, left knee, and bilateral knees were $29.00\pm 5.35$, $24.78\pm 3.74$, and $33.02\pm 6.80$, respectively. Significant positive correlations were found between BMI and PC ($r=0.35$) whereas significant negative correlations existed between BMI and SE ($r=-0.30$). Significant predictive markers of BMI were PC ($\beta =0.21$) and SE ($\beta =-0.89$).

Conclusion: Body mass index, PC, and SE correlate significantly in individuals with knee OA. The results call for the routine integration of psychologically-informed physiotherapy practice in the management of knee OA.