Sex-related differences in pain

This article provides an overview of sex-related differences in musculoskeletal pain and the role sex hormones and response to analgesic drugs may play in these differences. Some common pain conditions that include temporomandibular disorders, rheumatoid arthritis, fibromyalgia syndrome and tension-type and migraine headaches, show fairly marked sex-related differences in their occurrence, however, with the exception of rheumatoid arthritis, these pain conditions are also characterized by a lack of understanding of their basic underlying pathophysiology. The association of pain symptoms of these musculoskeletal pain conditions with the reproductive cycle of women is strongly suggestive of a role of the estrogens and/or progesterones, the main female sex hormones, in sex-related differences in pain. Nevertheless, an alternative suggestion that testosterone, the major mate sex hormone, protects men from these chronic musculoskeletal pain conditions, has also been made. Indeed, emerging evidence suggests that both male and female sex hormones may contribute to the marked sex-related differences in the occurrence of certain musculoskeletal pain conditions. Men and women also appear to differ in response to pain treatment with certain analgesic drugs. The mechanistic basis for these sex-related differences is not entirely understood but sex hormones are thought to be one of the influencing factors. An improved understanding of mechanisms which underlie sex-related differences in musculoskeletal pain and response to analgesic drugs should permit improved pain management strategies for male and female musculoskeletal pain patients in the clinical setting. (C) 2009 Elsevier Ireland Ltd. All rights reserved.