Temporomandibular disorders: Prevalence and associated biopsychosocial factors. An analysis of data from the NAKO Health Study

BACKGROUND: "Temporomandibular disorders" (TMD) is an umbrella term for symptoms in the area of the temporomandibular joints and muscles of mastication. TMD constitute one of the more common types of musculoskeletal pain. Previous estimates of the prevalence of TMD suffered from methodological limitations. The NAKO Health Study enables, for the first time, an examination-based estimate of the prevalence of painful TMD in a large population sample. METHODS: The baseline survey (2014-2019) was carried out in a partial population sample and involved standardized examinations of jaw mobility and palpation of the muscles of mastication. Painful TMD was recorded when a positive pain history was combined with pain that could be localized and induced on examination. Crude and adjusted prevalences were calculated, and associations with putative etiological and associated factors were analyzed by logistic regression. RESULTS: Of the 20 603 participants, 10.9% reported jaw or facial pain in the preceding month. The point prevalence of painful TMD was 3.7% overall and 6% among persons aged 20-29. TMD was more common in women, with an odds ratio of 2.72 (95% confidence interval: [2.28; 3.25]), as well as in smokers (1.42 [1.16; 1.74]) and in participants reporting sleep disturbances (1.96 [1.6; 2.4]), childhood trauma (1.11 [1.08; 1.14] per scale point), anxiety (1.12 [1.09; 1.14] per scale point), or depression (1.11 [1.09; 1.13] per scale point). Orthodontic treatment before the age of 19 did not increase or decrease the likelihood of painful TMD. Abnormal tooth and jaw positions were associated with a lower prevalence. CONCLUSION: Painful TMD is a common health problem that is not associated with dental morphological abnormalities, but rather with various biopsychosocial factors. These findings underscore the need for interdisciplinary diagnosis and treatment.