Comorbidities in chronic temporomandibular disorder patients: the links between painful and non-painful conditions

Painful and non-painful comorbidities are prevalent in patients with temporomandibular disorders (TMD) pain. The primary objective of this study was to assess the relationship between painful and non-painful medical comorbidities, and TMD pain. Our secondary aim was to evaluate how these relationships are modified by age and gender. Sample data was obtained from the National Institute of Dental and Craniofacial Research Temporomandibular Joint Implant Registry and Repository (NIDCR’s TIRR). Patients completed a questionnaire assessing a large number of medical conditions, pain characteristics (e.g., intensity, duration, frequency, and type of pain), disability, and demographics. Reproducible muscle pain during palpation was also included in this analysis. Factor analysis was performed using varimax rotation (SAS, version 9.2). A total of 500 TMD subjects aged 18 to 65 years were included in this study. Statistical analysis identified 6 major factors associated with TMD pain: 1) chronic-pain-disability (8.4% of variance), 2) psychological factors (4.3% of variance), 3) work activity (2.3% of variance), 4) endocrine-cholesterol disorders (1.7%of variance), 5) musculoskeletal-allergy-eating disorders (1.5% of variance), and 6) cardiovascular disorders (1.4%of variance). These factors are modified by age and sex. Our results indicate that painful, psychological and medical conditions are associated with TMD pain. They may reflect underlying shared mechanisms of chronic pain. This study was funded by NIH/NIDCR grants # RO1DE11252 and # DE09737-09.