Characterisation of the correlation between standing lordosis and degenerative joint disease in the lower lumbar spine in women and men: a radiographic study

BACKGROUND Degenerative joint disease (DJD) in the lumbar spine is a common condition that is associated with chronic low back pain. Excessive loading of lumbar joints is a risk factor for DJD. Changes in lumbar lordosis significantly redistribute the forces of weight-bearing on the facet joints and the intervertebral discs. However, the relationship between lumbar lordosis and DJD has not been characterized in men and women. METHODS We characterised the correlation between standing lumbar lordosis and DJD in standing radiographic images from 301 adult female and male chiropractic patients. DJD was rated using the Kellgren-Lawrence scale, and lordosis was measured using the Cobb angle. Linear and curvilinear correlations were investigated while controlling for age and sex. RESULTS We found a highly significant curvilinear correlation between lordosis and DJD of the lower lumbar spine in both sexes, but especially in women, irrespective of the effects of age. We found the effect size of lordosis on lower lumbar DJD to be between 17.4 and 18.1% in women and 12.9% in older men. In addition, lordosis of 65 (95% CI 55.3-77.7) and 68 (98% CI 58.7-73.3) degrees were associated with minimal DJD in the lower lumbar spine of women and men respectively, and were therefore considered 'optimal'. This optimal lordotic angle was 73 (95% CI 58.8-87.2) degrees in older men. CONCLUSIONS Both hypo- and hyper-lordosis correlate with DJD in the lumbar spine, particularly in women and in older men. These findings may well be of relevance to spinal pain management and spinal rehabilitation.