Signs and symptoms of first-onset TMD and sociodemographic predictors of its development: the OPPERA prospective cohort study

Abstract

Although cross-sectional studies of temporomandibular disorder (TMD) often report elevated prevalence in young women, they do not address the risk of its development. Here we evaluate sociodemographic predictors of TMD incidence in a community-based prospective cohort study of U.S. adults. Symptoms and pain-related disability in TMD cases are also described. People aged 18 to 44 years with no history of TMD were enrolled at 4 study sites when they completed questionnaires about sociodemographic characteristics. During the median 2.8-year follow-up period, 2,737 participants completed quarterly screening questionnaires. Those reporting symptoms were examined clinically and 260 had first-onset TMD. Additional questionnaires asked about severity and impact of their symptoms. Univariate and multivariable Cox regression models quantified associations between sociodemographic characteristics and TMD incidence. First-onset TMD developed in 3.9% of participants per annum, typically producing mild to moderate levels of pain and disability in cases. TMD incidence was positively associated with age, whereas females had only slightly greater incidence than males. Compared to whites, Asians had lower TMD incidence whereas African Americans had greater incidence, although the latter was attenuated somewhat after adjusting for satisfaction with socioeconomic circumstances.

Perspective: In this study of 18- to 44-year-olds, TMD developed at a higher rate than reported previously for similar age groups. TMD incidence was positively associated with age but weakly associated with gender, thereby differing from demographic patterns of prevalence found in some cross-sectional studies. Experiences related to aging merit investigation as etiologic influences on development of TMD.

Keywords: Temporomandibular disorder; demography; population characteristics; prospective cohort studies; socioeconomic factors.

Figure 1

Mean values for heterogeneous chronic pain sample (n = 6,532 people) are from Rudy. Error bars showing 95% confidence intervals for the heterogeneous pain sample are not visible because they are smaller than the boxes used as symbols.

Figure 2

Incidence rates of first-onset TMD were computed using multivariable Poisson regression models with multiple imputation to account for subjects who were not examined as intended. Covariates were study site (categorical variable, 4 levels), age (in years, with rates estimated for 3 selected age groups: 20, 30, and 40 years), race/ethnicity (5 categories), and lifetime U.S. residence (2 categories). The vertical axis has a maximum value of 10% per annum, truncating upper bounds of 95% confidence intervals for some rates. Hazard ratios (HRs) associated with 10-year difference in age (A and B) or with female gender (C) are shown with 95% confidence intervals in parentheses. They were calculated using multivariable Cox regression models with the same covariates described for the Poisson models. A includes an interaction term for age × race/ethnicity interaction (P = .055). B includes an interaction term for age × gender interaction (P = .79). C includes an interaction term for race × gender interaction (P = .76).

Figure 3

TMD incidence rates, expressed as cases per 100 person-years, were generated from random forest models that predicted TMD onset using study site and sociodemographic variables reported in Tables 4 and 6. Predicted values (●) are plotted together with loess-smoothed estimates (- - -) and their 95% confidence intervals (⋯). Age was reported in years, and satisfaction with material standards of life was rated on a scale from 0 (totally dissatisfied) to 10 (totally satisfied).