It is well known that central sensitisation conditions such as Fibromyalgia (FM) and Chronic Fatigue Syndrome (CFS) affect disproportionately more women than men. Indeed, the ratio is quite startling, with most studies putting the percentage of women affected at in excess of 75% and some as high as 90%. Also, men with Fibromyalgia often have fewer and milder symptoms than women.
A considerable amount of information has been published over the years as to why this might be the case and particularly the interrelated role of hormones and stress.
It has been established that the onset of Fibromyalgia peaks in women during their reproductive years. It is therefore believed that the female hormone oestrogen plays a significant role in the higher incidence of Fibromyalgia among women. The level of oestrogen in the body also seems to affect the severity of pain. Indeed, women with Fibromyalgia often report that the severity of their pain increases shortly before and during their periods and this coincides with levels of oestrogen falling prior to and during menstruation.
Levels of oestrogen are also very high during pregnancy and it is thought that this helps protect against the pain associated with pregnancy and childbirth.
Men do produce oestrogen in their bodies but at a significantly lower level than women and levels of this hormone in men do not fluctuate across the month.
The male hormone testosterone may also provide a degree of protection for men against pain. There is some evidence that men with naturally high levels of testosterone are less prone to developing Fibromyalgia. Conversely, it may also mean that the degree of protection against pain afforded by testosterone results in a significant proportion of men with Fibromyalgia going undiagnosed.
The role of stress
Evidence suggests that central sensitisation conditions such as Fibromyalgia are often triggered by stressful events such as an accident, surgery or even psychological trauma.
Studies show that in general, women react to stress differently to men. Whilst men tend to retreat more into themselves in stressful situations, women reach out and engage with others. The net result of this is that the effect of stress generally lasts longer in women than in men. This seems to be borne out by the fact that the proportion of women who suffer from chronic stress-related disorders such as depression, anxiety and irritable bowel syndrome is nearly double that of men.
Stress is known to make the symptoms of Fibromyalgia worse; often triggering a flare-up. There is also a body of opinion that hormonal changes in the body resulting from stress are actually a cause of Fibromyalgia.
In addition to the effect of stress lasting longer in women, it has been demonstrated that women have greater hormonal activity under stress compared to men. Accordingly, proving a link between stress-related hormonal changes and Fibromyalgia would go some considerable way to explaining the preponderance of Fibromyalgia among women. As with chronic pain more generally, far more research is needed.