These differences of susceptibility between males and females tend to appear after puberty, and flare-ups increase during pregnancy. Nine out of ten patients with lupus are women and clinical observations suggest that, again, hormones are the culprits. In the case of lupus, the immune system mistakenly attacks the person’s own DNA (the structure that carries a person’s genetic code) causing damage to multiple organs that will lead to weight loss, anemia and eventually heart and kidney failure. These diseases include type 1 diabetes, lupus, rheumatoid arthritis, multiple sclerosis, and up to 80 different diseases that affect systems such as the intestine, bones, joints and nervous systems. Women are three times more likely than men to develop these types of disease.Īutoimmune diseases occur when the immune system turns on and attacks the body’s own cells or tissues, initiating a chronic cycle that results in damage or destruction of specific organs. Autoimmune disease affects about 8% of the population, but 78% of those affected are women.
The most striking sex differences in the immune system are seen in autoimmune diseases. Thus, the hit to the male sex must somehow be balanced by other advantages to their immune system. The fitness of both sexes is necessary to reproduce long-term and thus provide new hosts for invading pathogens. However, this feature alone is not likely to be sufficient to ensure the ongoing survival of a virus. Because of this, many have adapted to be less aggressive in women allowing wider infection, generally across a population. Pathogens modify themselves so they can be transmitted by women during pregnancy, birth or breast feeding. However, this increased susceptibility of men to infection may not be an advantage for the long-term (over tens of thousands of years) survival of a disease-causing organism (pathogen), if it induces such severe disease that it results in the death of the host. While popular culture has come up with the term “man flu”, suggesting men are over-dramatising flu symptoms, evidence suggests they may in reality be suffering more due to this dampening down of their immune responses. Meanwhile, viruses have singled men out as the weaker sex. Viruses may have signalled men out as the weaker sex. Men are also five times more likely to develop cancer after infection with human papillomavirus (HPV), than women. For instance, men are 1.5 times more likely to die from tuberculosis, and twice as likely to develop Hodgkin’s lymphoma following Epstein–Barr virus (EBV) infection. Men die significantly more often from infectious diseases than women. Research suggests this has an evolutionary basis: survival of the species may mean men are harder hit by viruses, but a woman’s reactive immune system leaves her more susceptible to autoimmune diseases and allergies. But now we also recognise they have a major impact on the immune system - our body’s inbuilt mechanism that helps fight and protect us against disease. We know that sex hormones drive characteristic male and female traits such as breast enlargement and hip widening in women, or increased muscle mass and growth of facial hair in men.
In this series on Gender Medicine, experts explore these differences and the importance of approaching treatment and diagnosis through a gender lens.
Men and women respond differently to diseases and treatments for biological, social and psychological reasons.