The influence of age and BMI on intervertebral disc height and oropharyngeal airway in Japanese men and women

Objective Intervetebral disc height changes with both age and increasing body mass index (BMI), known risk factors for obstructive sleep apnea (OSA). We studied the relationship of body mass index (BMI) and aging in the neck structures to disc compression and oropharyngeal airway size and shape. Materials and methods The intervertebral disc (IVD), neck and airway volumes were measured at the C2 level only from Computerized Tomography scans using a semi-automatic segmentation tool. The change of intervertebral disc height/volume with age and BMI were examined in 38 consecutive Japanese patients (Male: 19, Female: 19), group matched for age (men: 52.2 +/- 15.36 years; women: 52.4 +/- 17.37) and BMI (men: 23.1 +/- 2.97 m/kg(2); women: 21.6 +/- 4.03 m/kg(2)). Results In this study, the intervertebral disc volume as a percent of neck volume was larger in men than in women (P = 0.039), and the intervertebral disc volume (r = -0.588; P = 0.013) and height (r = -0.510; P = 0.037) decreased with increasing age-adjusted BMI in males only. Age was not significantly correlated with any of the volumes. The intervertebral airway volume significantly decreased with increasing age-adjusted BMI in our female subjects (r = -0.588; P = 0.013). Conclusion In our Japanese volunteer population, the intervertebral disc is compressed vertically with the increase of BMI in males only, and the oropharyngeal airway volume decreases with increasing BMI in females only. These results may be useful in assessment of OSA risk.