Psychological Factors Associated With Development of TMD: The OPPERA Prospective Cohort Study

TL;DR: Evidence is provided that measures of psychological functioning can predict first onset of TMD, and several premorbid psychological variables predict first-onset TMD in the OPPERA study, a large prospective cohort study designed to discover causal determinants of T MD pain.

About: This article is published in The Journal of Pain.The article was published on 2013-12-01 and is currently open access. It has received 312 citations till now. The article focuses on the topics: Chronic pain.

Summary

Introduction

• Author manuscript; available in PMC 2014 December 01.
• The authors recently reported psychological findings from the OPPERA baseline case-control study, in which a cohort of participants meeting diagnostic criteria for chronic TMD were compared to a control cohort comprised of individuals who did not have TMD.30,78 Chronic TMD cases reported higher levels of psychological symptoms, affective distress, somatic symptoms, and pain catastrophizing compared to TMD-free controls.
• Through self-selection, slightly more than one-third of participants (ranged from 36.2% to 39.5% depending on the questionnaire) completed the instruments via paper and just under two-thirds completed them electronically, and mode of J Pain.
• This questionnaire assesses both positive and negative affective dimensions.

The Lifetime Stressor List/PTSD Checklist-Civilian Version (LSL/PCL-C)—The

• LSL presents a checklist of 15 different traumatic events, and participants indicate which (if any) of these events they have experienced.
• Author manuscript; available in PMC 2014 December 01.
• This measure has been reported to have adequate internal consistency, ranging from alpha of 0.73 to 0.83 in previous studies47 and 0.81 in their sample.
• Additional details regarding follow-up rates are provided in Bair, et al.5 Statistical Analysis A multi-stage analytic approach was developed to identify psychological characteristics that predicted TMD onset and to determine which psychological variables interacted with demographic factors and with other psychological variables in predicting risk for TMD onset.
• 1,35 Thus, a random forest model was used to address these shortcomings.

Measures of Global Psychological and Somatic Function, Stress and Mood

• (see Table 1)—Among the psychological characteristics reported in Table 1, the highest hazard ratio (HR) for predicting TMD onset emerged for the PILL (imputed HR=1.55), a measure of somatic symptoms.
• The effect was statistically significant, as demonstrated by the associated 95% confidence interval (1.33 to 1.66) that excluded the null of one.
• Also, greater scores on all SCL90R subscales were associated with increased incidence of TMD, with hazard ratios ranging from 1.22 (for the Phobia and Paranoid scales) to 1.44 for the Somatization scale.
• Both trait and state anxiety were associated with increased incidence of TMD, with hazard ratios of 1.4 and 1.22, respectively.
• Author manuscript; available in PMC 2014 December 01.

Measures of Active and Passive Coping and Reactivity (see Table 1)—None of

• The subscales of the Pain Catastrophizing Scale (Rumination, Magnification, Helplessness) predicted TMD onset to a statistically significant degree, although the Helplessness scale was weakly significant when using imputed data (HR=1.12).
• Likewise, no subscales from the Coping Strategies Questionnaire were statistically significant predictors of TMD incidence.
• As in their original PCA 30, a four-component solution emerged based on the scree plot and parallel analysis .
• The loadings for the PCA model are shown in Table 2.
• These four components were used in further univariate and multivariable analyses presented below.

Univariate Analyses of PCA Components as Predictors of First-Onset TMD—

• In univariate analyses of single PCA scores, high levels of Global Psychological and Somatic Symptoms (imputed HR=1.37) and Stress and Negative Affectivity (imputed HR=1.31) predicted increased TMD incidence in both the unimputed and imputed analyses while Passive Pain Coping was a weaker, though statistically significant, predictor of TMD incidence (imputed HR=1.16, see Supplementary e-Table 1 for detailed information).
• Table 3 presents the outcomes of analyses examining PCA components as predictors of TMD onset, stratified separately by age, gender, and race/ethnicity.
• In general, PCA components did not interact with demographic factors in predicting TMD onset, such that hazard ratios were similar across age groups, gender and race/ethnicity.
• Global Psychological and Somatic Symptoms was the exception, showing a modest interaction with age group (p=0.03), such that this component was a stronger predictor of TMD incidence in the two younger age groups compared to the 35–44 year old group.

Multivariable Analyses of PCA Components as Predictors of First-Onset TMD

• —In fully-adjusted models (i.e., including study site and demographic factors) that examined main effects of multiple PCA components predicting TMD incidence after controlling for the other components, Global Psychological and Somatic Symptoms remained the only strong predictor (imputed HR=1.33 , Table 4).
• The findings indicated that Global Psychological and Somatic Symptoms interacted with each of the other components in predicting TMD onset (all p’s < 0.01).
• Author manuscript; available in PMC 2014 December 01.
• Sullivan MJ, Bishop S, Pivik J. The Pain Catastrophizing Scale: development and validation.

Figures

Figure 1. Imputed TMD incidence rates and hazard ratios for stress and negative affectivity for three levels of Global Psychological and Somatic Symptoms. Each vertical bar depicts the TMD incidence rate for participants in the bottom (open bar), middle (light gray bar) and upper (dark gray bar) terciles of “Stress & Negative Affectivity” scores at each tercile (from left to right) of “Global Psychological and Somatic Symptoms” scores. Incidence rates of firstonset 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 three selected age groups: 20, 30 and 40 years), race/ethnicity (5 categories – rates not shown for

Frequently asked questions

Q1. What are the contributions in "Psychological factors associated with development of tmd: the oppera prospective cohort study" ?

For this study, 3,263 TMD-free participants completed a battery of psychological instruments assessing general psychological adjustment and personality, affective distress, psychosocial stress, somatic symptoms, and pain coping and catastrophizing. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to their customers the authors are providing this early version of the manuscript. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 

Q2. What was the second stage of the analysis?

The second stage of the analysis involved a series of multivariable Cox regression models in which the entered psychological variables were derived from a principal component analysis (PCA), which was performed in order to reduce the number of psychological variables by identifying putative latent constructs. 

Q3. What is the strongest predictor of TMD onset?

in univariate analyses as well as both multivariable approaches the somatic symptom construct represented the strongest predictor of TMD onset, suggesting convergence of findings regarding somatic symptoms across analytic methods. 

Q4. What was the significant predictor of TMD in the unimputed analysis?

The Stress and Negative Affectivity component was a weakly significant predictor in the unimputed analysis, but did not significantly predict TMD onset in the analysis using imputed data (HR=1.12). 

Q5. How many follow-up questionnaires did the inception cohort complete?

Of the 3,263 participants enrolled into the inception cohort, 2,737 (84%) completed one or more quarterly follow-up questionnaires, with a median of 10 follow-up questionnaires over a median 2.8 follow-up year period. 

Q6. What is the strongest predictor of incident TMD?

While multiple psychological measures predicted TMD onset in univariate analyses, results of multivariable models provide strong evidence that reported somatic symptoms represents the strongest predictor of incident TMD in this analysis. 

Q7. What is the principal component associated with the eigenvalues?

When the average eigenvalue from these randomly generated data sets is larger than the corresponding eigenvalue of the original data, then the principal component associated with that eigenvalue is likely to be random noise (see Supplementary e-Figure 1). 

Q8. What does the study suggest that stress and negative affect contribute to TMD?

This suggests that Stress and Negative Affectivity does not additively contribute to TMD risk over and above Global Psychological and Somatic Symptoms, rather in the absence of global symptomatology, stress/negative affect emerges as a potentially important risk factor. 

Q9. What is the CSQ Ignoring Pain Scale?

For the CSQ Ignoring Pain Sensations scale, TMD incidence was greatest at a score of 0 and decreased in linear fashion until a score of approximately two, beyond which incidence increased slightly. 

Q10. How did the parallel analysis determine the number of components to include in a PCA model?

Parallel analysis estimates the number of components to include in a PCA model by generating random data sets with the same numbers of observations and predictor variables as the original data. 

Q11. What did the authors find to be the significant predictor of incident TMD?

In univariate analyses, Stress and Negative Affectivity also predicted incident TMD; however, this association became weak or non-significant in multivariable analyses that adjusted for the other principal components. 

Q12. What was the effect of the Pain Catastrophizing Scale on the TMD?

the subscales of the Pain Catastrophizing Scale (Rumination, Magnification, Helplessness) predicted TMD onset to a statistically significant degree, although the Helplessness scale was weakly significant when using imputed data (HR=1.12).