Polyunsaturated Fatty Acids May Play Role in Temporomandibular Disorder Pain

Pain experienced by adults with temporomandibular disorder (TMD) was found to be strongly and inversely associated with erythrocyte omega-3 long-chain polyunsaturated fatty acid (PUFA) levels, according to results of a cross-sectional study published in the Journal of Pain.

Investigators from the University of North Carolina at Chapel Hill sourced data for this study from the Orofacial Pain Prospective Evaluation and Research Assessment (OPPERA-II) study, which was conducted between 2014 and 2016 and was the second phase of the OPPERA study. In OPPERA II, participants with painful TMD (n=543) and individuals with new-onset TMD (n=127) were evaluated for common coexisting painful conditions. The primary objective of the study was to determine the relationship between levels of PUFAs in circulating erythrocytes and pain outcomes.

This study evaluated pain intensity associated with orofacial pain, headache, low back pain, irritable bowel syndrome, and bodily pain. The correlations between pain intensity scores ranged from 0.31 (body and abdominal pain) to 0.71 (orofacial and headache pain).

Stratified by pain location, orofacial pain was assoicated with gender (P =.003) and smoking status (P =.006), headache pain was associated with gender (P <.001) and smoking status (P =.007), low back pain was associated with body mass index (BMI; P =.004) and smoking status (P =.017), abdominal pain was associated with gender (P <.001) and BMI (P =.011), and bodily pain was associated with BMI (P =.024) and smoking status (P =.035).

Stratified by pain phenotypes, the average omega-6/omega-3 PUFA ratio ranged from 0.89 among individuals who did not have headache pain (n=122) to 1.08 among those with fibromyalgia-associated body pain (n=47).

After adjusting for potential confounders, for every 1-point increase in omega-6/omega-3 PUFA ratio, low back pain intensity increased by 8.4 (95% CI, 3.8-13.0) points, orofacial pain intensity increased by 5.7 (95% CI, 1.4-9.9) points, body pain intensity increased by 5.3 (95% CI, 0.4-10.2) points, and headache pain intensity increased by 5.0 (95% CI, 0.9-9.2) points.

To understand the significant precursor components of the omega-6/omega-3 PUFA ratio, standardized concentrations of linoleic acid, arachidonic acid, alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid were compared with pain intensity scores. Docosahexaenoic acid Z-scores were associated with orofacial pain intensity (β, -36.7; P =.004) and headache pain intensity (β, -25.7; P =.038), and arachidonic acid Z-score was associated with low back pain intensity (β, 3.3; P =.045) in the adjusted analyses.

This study was limited by the small number of PUFAs evaluated.

These data indicate that for adults with persistent pain associated with TMD, omega-6/omega-3 PUFA ratio may play a role in pain intensity. The study authors state, “Our own studies showed that adults with a higher n-6/n-3 long-chain PUFA ratio in erythrocytes had lower pressure pain thresholds, greater psychological distress, and higher odds of chronic TMD.” The research suggests that altering dietary habits may be a potential intervention strategy for managing pain among patients with TMD.