What is Lupus?
Lupus is a chronic, autoimmune disease that affects more women than men. If you have lupus, your risk is higher for other health problems that are common in women, such as osteoporosis and heart disease. Lupus is a chronic autoimmune disease that can damage any part of the body. With autoimmune diseases, the body’s immune system cannot tell the difference between viruses, bacteria, and other germs and the body’s healthy cells, tissues, or organs. Because of this, the immune system attacks and destroys these healthy cells, tissues, or organs.
Lupus and Woman. Lupus is thought to develop due to an interaction between genetic susceptibility and environmental triggers. A number of genes referred to as lupus susceptibility genes, the presence of which are thought to increase the likelihood of developing lupus. Importantly, lupus is about 9 times more common in women than in men. This increased susceptibility may be made possible, at least in part, due to differences related to hormones and sex chromosomes. However, to what extent these sex differences contribute to the development of lupus is largely unknown.
Genetic samples were processed according to strict quality guidelines to determine the frequency of small but important changes in eighteen known lupus susceptibility genes found on non-sex chromosomes in both women and men with and without lupus. Based on differences from this analysis, including a subset of the genetic samples, a genetic risk was calculated for the lupus patients in a sex-specific manner.
Changes in 10 of the 18 susceptibility genes in men and 15 of the 18 in women were found to be significantly different between lupus patients and healthy people. Three of the 18 genes did not meet these criteria, were not associated with lupus in the current study, and were thus excluded from further analyses.
Comparison of the frequency of changes in the eighteen lupus susceptibility genes between women and men with lupus indicated that 4 of them differed significantly in a sex-specific fashion. 2 of these genes are found in the human leukocyte antigen (HLA) region (hereafter referred to as “HLA genes”) and two are found outside of the HLA region (hereafter called “non-HLA genes”). The HLA genes encode for proteins that are essential for proper functioning of the immune system and help to elicit powerful and specific immune responses.
Tthe frequency of the 2 HLA genes (plus one of the non-HLA genes, IRF5, a gene involved in the interferon pathway which is important in the pathogenesis of lupus) was significantly greater in men than in women with lupus. Only 1 of the 4 genes of interest here, one of the non-HLA genes (KIAA1542, a gene of unknown function), was significantly greater in frequency in women than in men. Importantly, the frequency of these three genes did not differ between women and men without lupus.
No significant sex-related differences were found in levels of anti-dsDNA between women and men with lupus. Further statistical comparisons showed that the frequency of changes in the four aforementioned lupus susceptibility genes were not associated with differences in disease severity in women or men with lupus.Comparisons of sex-specific differences in genetic risk showed that men with lupus require, on average, a greater cumulative genetic load of lupus-susceptibility genes than women in order to develop lupus.
The results indicate that men need to inherit a greater number of lupus susceptibility genes than women in order to develop lupus. Since the genes analyzed in this study were only genes outside of the sex chromosomes, the findings suggest that sex differences in lupus susceptibility genes are at least partially related to factors beyond sex chromosomes and hormonal differences. These results help to explain, at least in part, why fewer men get lupus than women.
How does lupus affect women?
Lupus is most common in women ages 15 to 44, or during the years they can have children. Lupus can make these problems happen earlier in life compared to women who do not have lupus.
These health problems include:
Kidney disease. More than half of all people with lupus have kidney problems, called lupus nephritis.5 Kidney problems often begin within the first five years after lupus symptoms start to appear. This is one of the more serious complications of lupus. Also, kidney inflammation is not usually painful so you don’t know when it’s happening. That is why it’s important for people with lupus to get regular urine and blood tests for kidney disease. Treatment for lupus nephritis works best if caught early.
Heart disease. Lupus raises the risk of the most common type of heart disease, called coronary artery disease (CAD). This is partly because people with lupus have more CAD risk factors, which include high blood pressure, high cholesterol, and type 2 diabetes. Lupus causes inflammation (swelling), which also increases the risk for CAD. Women with lupus may be less active because of fatigue, joint problems, and muscle pain, and this also puts them at risk for heart disease. In one study, women with lupus were 50 times more likely to have chest pain or a heart attack than other women of the same age.4
Osteoporosis. Medicines that treat lupus may cause bone loss. Bone loss can lead to osteoporosis, a condition that causes weak and broken bones. Also, pain and fatigue can keep women with lupus from getting physical activity. Staying active can help prevent bone loss.