Nonspecific orofacial symptoms as risk factors for first-onset TMD and chronic TMD (2015)

Undergraduate: Jenny Sun

Faculty Advisor: Eric Bair
Department: Biostatistics

---

Previous studies found that nonspecific orofacial symptoms were one of the most important predictors of first-onset TMD. We examined the influence of these symptoms (jaw siftness, cramping, fatigue, pressure, soreness, and ache) on first-onset TMD and chronic TMD among U.S. adults aged 18 to 44 years in the OPPERA study. We identified 259 first-onset cases and 185 chronic cases. Hazard ratios were computed to estimate the association between each nonspecific orofacial symptom and first-onset TMD. We calculated odds ratios to measure the association between each symptom and chronic TMD. A principal component analysis was used to determine if all 6 symptoms are measures of a single underlying construct or largely independent of one another. Multivariable cox models quantified the combined effects of non-specific orofacial symptoms, pain measures, and first-onset TMD. Multivariable logistic models examined these same associations on chronic TMD. Each nonspecific orofacial symptom was associated with increased incidence of first-onset TMD and greater odds of chronic TMD. Results from the PCA suggest we can summarize the six variables by simply counting the number of symptoms reported. In multivariable analysis, nonspecific orofacial symptoms significantly predicted first-onset TMD (HR=1.33; 95% CI:1.11-1.59) and chronic TMD (OR=3.06; 95% CI:2.03-4.97). This suggests the count of nonspecific orofacial symptoms is an independent risk factor and not a surrogate variable for pain.