Cross-sectional associations of fatigue subtypes with pain interference in younger, middle-aged, and older adults with chronic orofacial pain

Objective. Mental, emotional, physical, and general fatigue, as well as vigor, have each been associated with pain interference-defined as pain-related disruption of social, recreational, and work-related activities-in patients with chronic orofacial pain (COFP). The objectives of the current study were to compare levels of these fatigue subtypes across younger, middle-aged, and older patients with COFP and test the associations between fatigue subtypes and pain interference in these age groups. Design. A cross-sectional cohort design was used. Setting. Participants selfreported fatigue subtypes (Multidimensional Fatigue Symptom Inventory-Short Form), pain interference (West Haven-Yale Multidimensional Pain Inventory), pain intensity (visual analog scale), pain duration (months), depression (Symptom Checklist 90-Revised), and sleep quality (Pittsburgh Sleep Quality Index) at their initial appointment at a tertiary orofacial pain clinic. Subjects. Sixty younger (age 18-39), 134 middle-aged (age 40-59), and 51 older (age 60-79) COFP patients provided data for the study. Methods. Analysis of variance was used to compare levels of fatigue subtypes between the age groups. Regression with dummy-coding was used to test if the relationship between fatigue subtypes and pain interference varied by age. Results. Older COFP patients reported less general fatigue and more vigor than younger or middle-aged adults. Fatigue subtypes were each associated with greater pain interference, but associations became nonsignificant after controlling for depression, sleep, and pain intensity/duration. Age group-by-fatigue subtype interactions were not observed. Conclusions. Managing fatigue may be important to reduce pain interference in COFP populations and may be accomplished in part by improving depression and sleep.