New research by University of North Carolina Chapel Hill investigators shows that young women with temporomandibular joint disorders (TMD) are four times more likely to be current or former smokers than women of any age who have no clinical signs of TMD.
Moreover, TMD sufferers of all ages were three times more likely to have a history of skin rashes, allergies or hives or sinus troubles than women without TMD.
The lead investigator, Dr. Anne Sanders, and colleagues in the Center for Neurosensory Disorders at UNC analyzed data from nearly 300 women aged 18 to 60 enrolled in a case control study designed to identify factors associated with chronic TMD. TMD cases were identified by clinical examination using the Research Diagnostic Criteria for Temporomandibular Disorders. Perceived stress and inflammatory cytokines were among other variables also considered.
“Our findings refute the notion that analgesic properties of nicotine relieve chronic TMD pain,” Sanders said. “In fact, long-term smoking leads to changes in pain perception such that smokers deprived of nicotine are likely to show greater sensitivity to pain triggers.” What these findings indicate is that women, especially young women, should avoid turning to smoking as way to manage their pain and the anxiety it evokes. Although former smokers were more likely than lifetime nonsmokers to have TMD, the association of TMD with smoking was weaker in former smokers than current smokers. While this implies that quitting smoking may help, whether smoking cessation leads to a reduction in TMD pain is not something that could be addressed in this study. The good news is that smoking cessation is likely to health benefits for inflammation function, psychological health and allergic type conditions such as allergic rhinitis and hives.
The study is the first ever to compare the relationship between smoking and TMD across different age groups. It is also the first study to report evidence that lifetime history of allergy-type conditions are reported more commonly among people with TMD. “While our observation of an association between allergy and TMD is interesting, we are yet to understand the biological processes underlying this association” Sanders noted. The investigators plan to explore these relationships in greater detail in the longitudinal OPPERA study where smoking status and history of allergy are measured in both female and male participants before the first-onset of TMD.
Support for the study was provided by the National Institutes of Health.
We thank Dr. Anne Sanders, Assistant Professor in the Department of Dental Ecology, School of Dentistry at the University of North Carolina at Chapel Hill, for writing this summary article for the TMJA.
Dr. Sander's research investigates the epidemiology of oral diseases and disorders, with special emphasis on exploring how social factors influence oral health. Dr. Sanders is President of the Behavioral, Epidemiologic and Health Services Research Group of the International Association for Dental Research (IADR) and is Associate Editor for BMC Public Health. In teaching, she directs a course titled, “Epidemiology and Prevention I” offered to first year dental students and is course director of “Applied Research Methods” for graduate students.