Does obesity affect the efficacy of therapeutic exercise on pain intensity and disability in patients with chronic non-specific low back pain?

Aims and Despite the rapid growth and prevalence of obesity, the impact of obesity on outcome of exercise therapy in patients with chronic non-specific low back pain is still uncertain. The aim of this study was to investigate whether obesity can affect the efficacy of exercise therapy on pain and disability of patients with chronic non-specific low back pain.
Study subjects include 32 male and female (21 men and 11 women) patients with chronic non-specific low back pain.They were classified Based on body mass index (BMI) and waist-to-hip ratio (WHR) into two groups of obese subjects (6 men , 4 women; mean age: 52.3±5.85 and BMI 32.45±2.15) and non-obese (15 men and 7 women; mean age, 51.81±7.10 and BMI 24.5±1.91). To assess pain visual analogue scale (VAS)was used and Roland Disability Questionnaire - Morris (RMQ) was used to assess back pain disability. Exercise program consisted of seven exercises which was carried out for 10 weeks, three times a week for 30 to 60 minutes. Data wasanalyzed by independent t test, ANOVA and Pearson correlation tests with the significant level of less than 0.05.
Findings: The results showed a significant difference between pain intensity (F=-2.88, P=0.007) and disability (F=-2.16, P=0.04) of obese and non-obese subjects with chronic non-specific low back pain in pretest.A statistically significant relationship between body mass index and pain severity (r =0.43, p=0.02) and disability (P=0.49, p=0.017)was observed in patients with chronic non-specific low back pain. After the intervention, pain (F=14.27, p=0.001) and disability (F=5.42, p=0.03) improvement was significantly more for non-obese than obese chronic non-specific low back pain subjects.
The results showed that obesity has a negative impact on efficacy of exercise therapy in patients with chronic non-specific low back pain. Accordingly, it seems that therapeutic approaches which target both body weight and back pain in obese patients with chronic non-specific low back pain,have more significant economic effect and even better long-term outcomes not only for pain but also for other complications associated with obesity.