Papers of the Week

Co-occurring pain conditions that affect overlapping body regions are complicated by the distinction between primary versus secondary pain conditions. We investigate the occurrence of headache and painful temporomandibular disorder (TMD) in a community-based, cross-sectional study of U.S. adults in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA-II) study. A specific goal was to determine if headache attributed to TMD is separable from primary headache.Using DC/TMD and ICHD-3 criteria, three groups of individuals were created: a) headache without TMD; b) headache comorbid with TMD; and c) headache attributed to TMD. Regression models compared study groups according to demographic and comorbid characteristics, and post-hoc contrasts tested for differences. Descriptive statistics and Cohen's d effect size were computed, by group, for each predictor variable. Differences in continuous predictors were analyzed using one-way ANOVA.Nearly all demographic and comorbid variables distinguished the combined headache and TMD groups from the group with headache alone. Relative to the reference group with primary headache alone, markers related to headache, TMD, somatic pain processing, psychosocial, and health conditions were substantially greater in both headache comorbid with TMD and headache attributed to TMD, attesting to their qualitative similarities. However, effect sizes relative to the reference group were large for headache comorbid with TMD and larger again for headache attributed to TMD, attesting to their separability in quantitative terms.In summary, the presence of overlapping painful TMD and headache adds substantially to the biopsychosocial burden of headache and points to the importance of comprehensive assessment and differential management.