Impact of Cytokine Genes on TMD and QoL in Construction Workers

Temporomandibular disorders (TMD) include changes related to the presence of orofacial pain, limited mouth opening, and inflammatory issues. These inflammatory issues are related to interleukins, which are inflammatory mediators. Thus, the presence of genetic polymorphisms in genes that encode interleukins could impact TMD. Therefore, this cross-sectional study aimed to assess the impact of genetic polymorphisms in the genes encoding interleukins on the oral health-related quality of life (OHRQoL) of individuals with TMD. A total of 230 male construction workers were evaluated regarding the presence of TMD with or without pain, as well as changes in the temporomandibular joint (TMJ), using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). OHRQoL was assessed using the 14-item Oral Health Impact Profile (OHIP-14). DNA extracted from saliva was used to evaluate the genetic polymorphisms in IL1B (rs1143627 and rs1143629) and IL6 (rs1800795 and rs1800796) using real-time polymerase chain reaction. Student's t-test or ANOVA was used for statistical analysis (alpha=5%). An association between OHIP-14 and TMD was observed (p<0.05). Individuals' heterozygous AG in rs1143629 showed increased values in domains 2 (physical pain) and 4 (physical disability) compared to AA homozygotes (p=0.035; p=0.042, respectively). Individuals homozygous for the C allele at rs1800796 demonstrated higher values in domain 7 (handicap) compared to heterozygous CG and homozygous GG individuals (p=0.007). In conclusion, our study supported the hypothesis that TMD and genetic polymorphisms associated with inflammatory disorders are associated with OHRQoL.