GENDER AND HORMONAL EFFECTS ON CLINICAL TMJD PAIN

摘要

Temporomandibular muscle and joint disorder (TMJD) pain is about twice as common in women as in men; peak prevalence occurs during the reproductive years. Although the majority of common pain conditions show higher female prevalence, the peak seen in TMJD pain prevalence during the reproductive years does not occur for most other pain conditions. This suggests that, in addition to generic factors affecting pain in women, TMJD pain may be influenced by factors specific to this time of life. Studies of the association of TMJD with hormone replacement therapy, as well as changes in clinical TMJD pain across the menstrual cycle and during pregnancy, have found an association between the occurrence and severity of TMJD pain and the presence and level of estrogen. Specifically, estrogen appears to be a pain modulator, such that high pain occurs at times of lowest estrogen, whereas higher levels of estrogen are associated with lower pain report. However, TMJD pain prevalence does not increase dramatically in girls until three to five years after menarche, suggesting that repeated exposure to estrogen fluctuations may be necessary to trigger onset. Studies also indicate that psychological distress and pain are strongly related and show similar patterns in relation to hormones. These data are supportive of the hypothesis that these hormonal influences act at the level of the central nervous system. If the influences are central, hormones may influence other pain conditions in women as well, but TMJD pain presents a particularly dramatic example of this phenomenon.