Sex-Specific Associations between Schmorl Nodes, Modic Change, and Osteoporosis in the Low Thoracolumbar Spine in a Large Population-Based Study: The Wakayama Spine Study.

Abstract

Background: The study examined sex-specific associations between Schmorl's nodes (SNs), Modic changes (MC), and osteoporosis (OP) in the low thoracolumbar region (Th10/11-L5/S1) using magnetic resonance imaging (MRI).

Methods: This study included 970 participants (317 males, mean age=67.2 years; 653 females, mean age=66.0 years) aged 21-97 years from the Wakayama Spine Study. SN was defined as a small, well-defined herniation pit with a surrounding wall of hypointense signal. MC was defined as a diffuse high-signal change along either endplate. OP was defined according to the Japanese Society for Bone and Mineral Research criteria. We evaluated the prevalence of SN at each level and its detailed distribution in males and females. Univariate logistic regression analysis examined the association between the presence of SN in the low thoracolumbar region and age strata, body mass index (BMI), OP, and MC in males and females. Multiple logistic regression analysis identified independent factors, with significant factors in the univariate logistic regression analysis used as independent variables.

Results: In females, but not males, advanced age was significantly associated with SN after adjustment for smoking and alcohol (50-59 years: odds ratio [OR] 3.2; 60-69 years: OR 6.0; 70-79 years: OR 12.1; >80 years: OR 14.8). OP and BMI were not significantly associated with SN in either males or females. MC was significantly associated with SN in females (OR, 1.5).

Conclusions: This study demonstrated that SN was associated with MC, but not OP, in females. These findings may help elucidate the causes and mechanisms of SN.