The Association Between Body Mass Index (BMI) and Back or Leg Pain in Patients With Spinal Conditions: Results from the Genodisc Study.

STUDY

DESIGN

A prospective observational study.

OBJECTIVE

The aim of this study was to identify the relationship between obesity, quantified by body mass index (BMI), and both back and leg pain in spinal patients.

SUMMARY OF BACKGROUND DATA: Obesity and back pain are massive public health problems. Given the poor correlation between pain and a pathological change in the spine, further investigation is required into other, nonpathological predictors such as obesity.

METHODS

The Genodisc Study was one of the largest cross-sectional studies of patients presenting to tertiary spinal units and recruited from six centers in four European countries. In total, 2636 patients were recruited over a 5-year period between 2008 and 2013. Both back and leg pain were scored by patients in the range of 0 to 10. Linear regression was used to model the relationship between BMI and pain. Potential confounders included in the model were age, Zung Depression score, episodes of sport, gender, disability benefit, family history, previous surgery, smoking status, work type, clinical diagnosis, and relevant comorbidities. Back and leg pain outcomes were modeled separately.

RESULTS

The study included 1160 men and 1349 women with a mean age of 50.9 years and mean BMI of 27.2 kg/m. In our fully adjusted model, a 5-point increase in BMI was associated with greater leg [0.19 units (95% confidence interval 0.08-0.31)] but not back [0.10 units (95% CI -0.02 to 0.22)] pain scores. Although this relationship was statically significant, given the small magnitude of the relationship, the clinical significance is limited. Similarly, female gender, heavy workload, rheumatoid arthritis, previous spine surgery, and depression were associated with higher back and leg pain.

CONCLUSION

In this large observational study of spine patients presenting to tertiary European centers, obesity, as measured by increased BMI, was associated with greater leg pain.

LEVEL OF EVIDENCE: 2.