A study by University of Washington researchers has identified a possible link between the use of hormone therapies and incidence of TMD among women. The findings are reported in the January issue of Pain.
TMD, medical and dental conditions characterized by pain in the muscles of the face and the temporomandibular (jaw) joint, are up to twice as common among women, especially those of childbearing age. In their study, Dr. Linda LeResche, research associate professor at the UW School of Dentistry, and colleagues studied a group of post-menopausal women, including 1,291 who had been referred for treatment of TMD and 5,491 who were not referred for the disorder.
"We found that women receiving hormone replacement therapy were more than 70 percent more likely than non-users to be suffering from TMD," said LeResche. "These findings on hormone replacement suggest that a woman's own hormones could also increase her risk for TMD."
Additionally, researchers studied 1,400 women aged 15 to 35 with TMD and 5,600 controls. They found that those women using oral contraceptives were 20 percent more likely to have TMD.
"These results point to one possible reason why facial pain conditions are more common among women, " LeResche said. "Further research is needed to clearly identify hormones as a possible cause of TMD. If hormones play a causal role in TMD, most likely they are only one of many causal factors."
It is estimated that 10 million Americans suffer from temporomandibular disorders. While the cause of TMD is unknown, there are a range of theories about the condition and, likewise, a variety of treatment options. These treatments include techniques to reduce stress, medications to control pain and the use of mouth guards to protect teeth.
If the role of female reproductive hormones is substantiated in further studies, LeResche said it could lead to a range of treatments--some as benign as increased self-monitoring of TMD conditions at times when hormone levels are changing.
The study was funded by the National Institutes of Health's Office of Research on Women's Health and the National Institute of Dental Research.