Objective: To explore the relationship betweensleep/psychological distress and temporomandibular disorders (TMD) and to discuss the possibility of disturbed sleep and psychological distress as risk indicators in relation to TMD in a Chinese population.
Methods: The standardized and validated self-reported Chinese version questionnaires including Pittsburgh sleep quality index (PSQI) and depression, anxietyandstress scales-21 (DASS-21) were used to measure sleep quality and psychological distress. A total of 755 TMD patients (172 males and 583 females)with a mean age (29.99 ± 13.60) years were included in the study. The patients were divided into 7 diagnostic groups based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), including Group I(exclusively myofascial pain), Group II(exclusively disc displacement), Group III (exclusively arthralgia or degenerative joint disease), Group IV (myofascial pain plus disc displacement), Group V (myofascial pain plus arthralgia or degenerative joint disease), Group VI (disc displacement plus arthralgia or degenerative joint disease) and Group VII (myofascial pain plus disc displacement plus arthralgia or degenerative joint disease). For statistical analysis, the patients were subsequently grouped into those with (181 patients) and without (574 patients) myofascial pain. Chi-square tests, independent-samples t test, partial correlation as well as stepwise Logistic regression analysis were used to analyze the data, using software SPSS 20.0 and P<0.05 was of significance.
Results: The prevalence of moderate to (extremely) severe disturbed sleep and psychological distress was significantly higher in the myofascial pain group (27.1%, 28.7%, 60.8% and 32.0%) than in the non-myofascial pain group (disc displacement and arthralgia or degenerative joint disease, 11.1%, 10.1%, 27.4% and 11.0%, P<0.05).The comorbidity of self-reported disturbed sleep and psychological distress was significantly higher in the myofascial pain patients than those without myofascial pain (P<0.05). Stepwise logistic regression analysis demonstrated that disturbed sleep (OR=1.74), more specifically, subjective sleep quality (OR=1.69) and sleep disturbance (OR=1.63) respectively, anxiety (OR=3.14) and stress (OR=2.15) were possible risk indicators for myofascial pain, and the results were still significant even after controlling for age, sex, educational level, disease duration, sleep quality, depression, anxiety and stress respectively (P<0.05).
Conclusion: Disturbed sleep and psychological distress symptoms are common in TMD patients. Disturbed sleep, anxiety and stress are possible risk indicators for myofascial pain, compared with disc displacement and arthralgia or degenerative joint diseases.