Health Claims Study Suggests Link Between Parkinson Disease and TMD

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Patients with Parkinson disease appeared to have more than a 2-fold higher risk of developing temporomandibular disorder, known as TMD, in a study that evaluated health insurance data from Taiwan.

Individuals with Parkinson disease (PD) may have elevated odds of developing temporomandibular disorder (TMD) than people without PD, according to a study in PLoS ONE.

“The prevalence of temporomandibular disorder among elderly people with Parkinson’s disease is relatively high, but a population-based study of the relationship between PD and TMD is still lacking," researchers said. "This study, therefore, sought to investigate the association between TMD and PD by using data for one million randomly sampled beneficiaries of Taiwan’s National Health Insurance program."

Researchers examined data from National Health Insurance (NHI) recipients randomly sampled from the NHI Research Database. They identified 6185 patients with PD and conducted propensity score matching with 18,555 non-PD patients. The PD and non-PD cohorts were followed until death, diagnosis of TMD, or December 31, 2013. Patients in the PD group had a mean age of 70.2 years, a mean Charlson Comorbidity Index (CCI) score of 3.65, and 51.2% were male. Non-PD patients in the control group had a mean age of 70.0 years, a mean CCI score of 3.58, and 51.6% were male.


Qualified physicians diagnosed TMD with International Classification of Diseases, 9th Revision, Clinical Modification codes. At the conclusion of the 13-year study period, a total of 32 cases of TMD had occurred within the PD group and 50 occurred within the larger control group. Researchers conducted Cox proportional hazards regression analysis and found the incidence of TMD among patients in the PD group was:

  • 26.11 per 1000 person-years during the first year since initial PD diagnosis
  • 6.65 per 1000 person-years during the second year
  • 1.65 per 1000 person-years during the third year
  • 1.67 per 1000 person-years during the fourth year
  • 9.26 per 1000 person-years after the first 4 years

Incidence of TMD in the control group was:

  • 6.43 per 1000 person-years during the first year of follow-up
  • 1.94 per 1000 person-years during the second year
  • 0.90 per 1000 person-years during the third year
  • 3.26 per 1000 person-years during the fourth year
  • 1.31 per 1000 person-years after 4 years

The results indicated that PD patients had significantly higher odds of developing TMD than non-PD patients within the first and second year following their initial diagnosis.

After adjusting for age, sex, CCI score, geographic region, diabetes, hypertension, hyperlipidemia, and cardiovascular disease, researchers found there was a 2.11-fold higher overall risk of TMD for patients in the PD group compared to the control group. Stratified by follow-up period, there was a 4.25-fold greater risk for the PD group in the first year after initial PD diagnosis and a 3.88-fold greater risk in the second year. Over a span of 5 years, PD was found to be significantly associated with an increased risk of TMD. Patients who lived with PD for longer periods of time faced greater risks of developing TMD. Based on the study’s findings, researchers stressed the importance of closely monitoring the temporomandibular joint health of patients with PD.

“In conclusion, the results of this study demonstrated that the PD patients had an increased risk of TMD compared to the matched controls, with the difference being significant for 2 years after the diagnosis of PD," researchers said. "Understanding these long-term associations of PD with TMD, as well as the risk of causal motor symptoms, is of substantial value for those seeking to improve oral health policies."


Chen YYm, Fan HC, Tung MC, Chang YK. The association between Parkinson’s disease and temporomandibular disorder. PLoS ONE. 2019;14(6): e0217763. doi: 10.1371/journal.pone.0217763.