Ligamentous Ossification of the Cervical Spine in the Late Middle-Aged Japanese Men

STUDY DESIGN: The present study investigated the relationship of obesity and glucose metabolism in persons with ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament of the cervical spine. OBJECTIVE: To provide a insight into the etiology of ligamentous ossification of the cervical spine. SUMMARY OF BACKGROUND DATA: The high incidence of ligamentous ossification of the cervical spine with obese patients has been reported, but no definite association was reported between the incidence of ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament and their bone mass index values. METHODS: Lateral cervical radiographs and 75 g oral glucose tolerance tests of more than 4802 Japanese men aged 48-57 years at the Self Defense Force Hansin Hospital were evaluated. RESULTS: The incidences of ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament were 23.1% (1110 of 4802), 23.3% (1117 of 4802) and 4.1% (198 of 4802), respectively. In the groups whose body mass index was 25 or more, the incidences of ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament were significantly high (P < 0.01). The higher incidence of diabetes or impaired glucose tolerance was statistically significant in ossification of the anterior longitudinal ligament and ossification of the posterior longitudinal ligament but not in ossification of the nucal ligament. The rates, which showed significantly high glucose response by 1-hour or 2-hour plasma glucose level after oral glucose tolerance tests with body mass index-matched control subjects, were ossification of the anterior longitudinal ligament, 93.5%; ossification of the posterior longitudinal ligament, 52.0%; and ossification of the nucal ligament, 14.0%, respectively. CONCLUSIONS: From this study, obesity was shown to be the major risk factor of ossification of the nucal ligament, and obesity and glucose intolerance were risk factors in ossification of the anterior longitudinal ligament and ossification of the posterior longitudinal ligament. The authors concluded the morbidity rates of ossification of the anterior longitudinal ligament. ossification of the nucal ligament, and ossification of the posterior longitudinal ligament were high in obesity, however, concerning the glucose intolerance, ossification of the nucal ligament is etiologically different from ossification of the anterior longitudinal ligament and ossification of the posteior longitudinal ligament.