Who gets sicker, men or women?

Women get sick and men die - that's how the issue of gender differences in health has been cheerily summarised. Women live five years longer than men but are thought to spend it wracked with pains in their backs and suffering from late-onset angina.

Much of the evidence for women's ill health has come from questionnaires and their more frequent attendance at GP surgeries. In the case of some specific diseases, however, research has been looking at the differences between the sexes at a cellular level.

Autoimmune diseases (in which the immune system wrongly recognises its own body as foreign and starts a programme of self destruction) such as multiple sclerosis and rheumatoid arthritis are more common, and possibly more severe, in women.

According to an article in this week's Science, this may be because men and women have differences in their immune systems.

Women tend to produce an immune response that's typical for fighting viruses. Men, on the other hand, tend to produce protein substances called antibodies which come more into play fighting bacterial infections.

Although one daily newspaper reported the research in Science as meaning 'men are weaker at fighting off colds' (caused by various viruses), the truth is considerably less clear cut. The article in Science is far more subtle in what it says about immunological differences between the sexes.

Immunologists readily admit that their nomenclature is cumbersome even for experts. The immune response that predominates in men, for example, is called the TH2 lymphocyte response (lymphocytes are the white blood cells) and the cells produce proteins called IL-4, IL-5, IL-6, IL-10, and transforming growth factor B.

It's less exact, but also less dull, to say women's immune systems are better at hand-to-hand combat and men prefer chemical warfare.

As yet, there aren't the studies to show that women are better at fighting off colds than men. Or any studies to show differences between the sexes in fighting real infections.

There never will be, since it's not ethical to deliberately infect people in a controlled environment and see what happens. There is, however, evidence from vaccination that the immune systems of men and women behave differently. Typically girls have a more vigorous immune response than boys after being immunised against diseases.

There is also speculation that some differences may well have something to do with sex hormones; oestrogen and progesterone in women versus testosterone in men.

Oestrogen appears to have opposite effects at high and low levels. Some studies show women with MS get worse symptoms just before their periods but that their disease goes into remission with pregnancy (when oestrogen levels are very high), while in rheumatoid arthritis, remissions may be even more marked during pregnancy.

In the USA there's been sufficient interest in the issue of gender and autoimmunity for immunologists to set up a task force with what it says is an 'aggressive research agenda'.

Its chairwoman, Professor Caroline Whitacre from Ohio State University, says that they want researchers to always look at gender differences in their studies. More research may show, for example, whether women with MS should be treated at certain times in their menstrual cycles, or whether sex hormones themselves may be used to treat autoimmune diseases.

Whitacre says she'd like research into gender differences in melanomas and bowel cancer, since in both diseases the body has a go at mounting an immune response.

Differences in immunity between the genders will, at best, only ever explain a tiny bit of the variation between men and women's health. The US Task Force acknowledges that the environment and genetics (as ever) will be involved.

Also under the microscope is the common idea that women are generally sicker (in terms of non life-threatening disease). A paper in Social Science and Medicine earlier this year says that an analysis of the General Household Survey showed no differences between men and women in reporting ill-health.

The much repeated hypothesis that men are more stoic, say the authors, is therefore not valid. They also cite a British study of 1694 volunteers at a research unit for the common cold (now closed) between 1984-9 which asked men and women to rate their colds on a severity scale. Each day a medically qualified observer also graded the clinical severity of their cold. Men, said the researchers, were much more likely than women to 'over rate' their symptoms.

Time and more research will tell if the men's version of their snuffles actually do have a sound immunological basis.

Thanks to guardian.co.uk who have provided this article. View the original here.