Body mass index and its association with disc degeneration of the lumbar spine in adults

Abstract

The association of elevated body mass index (BMI) as a risk factor of disc degeneration remains questionable. As such, we addressed the association of BMI to the presence and severity of disc degeneration in adults. A cross-sectional analysis was performed of 2,252 individuals (range: 21-88 years) of Southern Chinese origin having undergone sagittal T2-weighted MRIs of the lumbar spine. The presence and severity of disc degeneration as well as additional radiographic and clinical findings were assessed. Asian-modified BMI (kg/m2) categories were established. There were 906 males and 1,346 females, with a mean age of 41.4 years. Disc degeneration was noted in 1,598 (71% ) subjects. BMI was significantly higher in subjects with disc degeneration (mean: 23.3 kg/m2) compared to subjects without disc degeneration (mean: 21.6 kg/m2) (p<0.001). Age- and workload severity-adjusted BMI was positively correlated with overall disc degeneration severity (r=0.450, p<0.001), the number of levels of disc degeneration (r=0.365, p<0.001), and the overall disc herniation score (r=0.230, p<0.001). In the adjusted logistic regression model, there was a positive linear dose-response between BMI and disc degeneration (underweight, 1 (Ref); normal, OR: 2.3, 95% CI: 1.57-3.23; overweight, OR: 3.2, 95% CI: 2.20-4.73; obese, OR: 5.3, 95% CI: 3.13-9.05; p<0.001). Our study showed a significantly increasing linear dose-response between BMI and disc degeneration of the lumbar spine. Increased severity of disc degeneration was also noted with elevated BMI, in particular overweight and obesity. BMI is an influential risk factor related to disc degeneration.