Correlation Between Bone Mineral Density (BMD) and Paraspinal Muscle Fat Infiltration Based on QCT: A Cross-Sectional Study.

To investigate the correlation between fatty infiltration of the paraspinal muscle and bone mineral density (BMD). In total, 367 subjects (182 men and 185 women) who underwent quantitative computed tomography (QCT) examination were enrolled in this study. A QCT Pro workstation was used to obtain the mean BMD of the lower lumbar spine (L3, L4, L5) and fat fraction (FF) of the paraspinal muscle (psoas and erector spinae) at the corresponding levels. The patient's age, sex, body mass index, number of previous vertebral fractures, physical activity level, and visual analog scale (VAS) score for lower back pain were recorded. For categorical variables, one-way ANOVA and independent-samples t tests were performed. Spearman and Pearson correlation coefficients were used to analyze the correlations among continuous variables. Influential factors were analyzed by multivariate linear regression analysis. Regarding the mean paraspinal muscle FF, there were significant differences between the different vertebral fracture groups (P < 0.05). Age and VAS score showed a positive correlation with the mean paraspinal muscle FF (r = 0.389, 0.454). BMD showed a negative correlation with the mean paraspinal muscle FF (r =  - 0.721). The multiple linear regression analysis showed that vertebral fracture (β = 0.851, P = 0.021) and BMD (β =  - 4.341, P = 0.004) were independent factors of the mean paraspinal muscle FF. This study demonstrated that an advanced age, a greater VAS score, a higher number of vertebral fractures, and a lower BMD may be associated with more severe fatty infiltration of the paraspinal muscle.