10 Nearly all the chronic pain syndromes, such as chronic fatigue syndrome, fibromyalgia, 11 and certain malignancies, have a female predominance. 9 Tension headache also has a female predominance with 46% of females having frequent tension headache compare to males at 38%. Some 86% of female chronic pain sufferers in a Swedish study were found to clench or grind their teeth. The study of chronic muscle syndromes, such as myofascial pain, jaw joint pathologies, 2 dysfunction, 3 atypical odontalgia, 4 Meniere’s disease, 5 Lupus, 6 burning mouth, 7 and cervical dysfunction, 8 all reveal a strong female pre-disposition.

Increasingly, research is linking chronic pain to gender. The exact reasons for this predisposition are difficult to research due to its multiple causes-hormonal influences, central sensitization (rewiring), and sympathetic system changes. In 2001, the ratio of females-to-males requesting examination at Raleigh Facial Pain Services was 84% and in 2002 it was 80%.

However, the actual number of women seeking care is closer to 10-to-1, or even as high as 15-to-1 for some chronic pain clinics. 1 In double-blind, randomized studies, the female-to-male ratio is 3-to-1 for chronic pain in most of the major head and neck pathologies. Pain in the cervical masticatory muscles (head pain) is one of the most common problems for females. “When fatty tissue receives signals from prolactin, it reacts by reducing the production of another hormone called adiponectin, which is important for the metabolism of a variety of nutrients,” explains Louise Nilsson.Neuromuscular problems (neck, back, and head pain) are the second most common pain next to viral- and bacterial-induced pain. An ongoing study suggests that the hormone impairs the body’s ability to maintain a balanced metabolism. Prolactin also affects the body’s ability to metabolise fat. This in turn increases the risk of cardiovascular disease.”

“We have demonstrated that prolactin reduces the ability of fatty tissue to store sugar and fat, which then could accumulate in the blood and certain tissues instead. In her thesis Louise Nilsson shows that there are receptors for the breast feeding hormone in human fatty tissue. “In recent years scientists have also recognised the role of prolactin in the development of obesity, but little research has been done into the precise mechanism by which prolactin regulates metabolism,” says Louise Nilsson. In women, an abnormally high level can cause menstrual disturbances and infertility, and may also result in insulin resistance. In many cases doctors don’t know what causes the rise in hormone levels. Women who are pregnant or breast feeding have naturally raised levels of prolactin, but stress, some medicines and benign brain tumours can also lead to raised levels of the hormone. Over 30 000 Swedish men and women may have raised levels of prolactin.

Nillson girls with muscle