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The Centers for Disease Control and Prevention in Atlanta tells us that there are about 160,000 confirmed and 330,000 "possible" cases of lupus, as defined by its severest symptoms, in the United States alone. ("Lupus" is the common term for the disease known as systemic lupus erythematosus, or SLE.) The Lupus Foundation of America estimates that as many as 1.5 million Americans have some symptoms caused by the disease, with certain ethnic groups affected disproportionately.
Lupus strikes 10 to 11 times more women than men, and it is most likely to strike during a woman's reproductive years. Men who carry two copies of the X chromosome, who are XXY rather than XY, are also especially susceptible to developing the disease. The course of the disease varies greatly from person to person, but it is not unusual for lupus to be benign for many years until it rapidly and unexpectedly progresses to a fatal condition.
Lupus makes living difficult, but scientists have a better understanding of the disease than ever before. Five surprising facts about lupus have emerged in recent scientific studies.
1. Lupus seems to be triggered by staph infections.
Staph, which is short for Staphylococcus aureus, is a common bacterium on the skin and on the mucous membranes of the nose and throat. Most staph infections are benign, and it is only when the natural population of bacteria on the skin or in the mucous membranes becomes unbalanced that staph infections cause symptoms.
Four researchers at the Mayo Clinic in Rochester, Minnesota have found that women who have lupus tend to have had greater exposure to staph bacteria. They believe that the staph bacterium, which has specialized defenses against white blood cells, sends the immune system on a "wild goose chase," eluding the action of those white blood cells. The overactive white blood cells may trigger a lupus attack, suggesting that one way to avoid exacerbations of lupus might be to be especially careful to avoid staph infections.
2. Exposure to radioactive materials may increase the risk of lupus.
Women who live near uranium processing plants, two reports have found, are at greater risk for developing lupus. At least one unpublished report has suggested that exposure to radon, a radioactive gas that accumulates in basements in much of the eastern United States, may also increase the risk of lupus. Avoiding uranium dust and making sure basements are well ventilated potentially reduces the rate of relapse in the disease.
3. Good cholesterol may go bad in Black women who have lupus.
Lupus often causes kidney disease, and it is especially likely to cause kidney disease in women of African descent. Researchers have noticed that Black women who get lupus tend to have an unusual form of "good" HDL cholesterol that activates the immune system. In Africa, this kind of cholesterol activates the immune system to fight certain fly-born parasites. In America and in the UK, however, this kind of cholesterol causes damage to the kidneys. This doesn't mean that it's a good idea to avoid raising your HDL cholesterol, but it make sure the doctor knows about any family history of lupus, or that you have lupus, before prescribing any cholesterol-altering or statin drug.
4. Stimulating the immune system in lupus is not necessarily a good thing.
Scientists have found that a defect in the normal process of "cellular suicide," or apoptosis, of certain kind of white blood cells increases the severity of lupus. When white blood cells don't die at the times and in the numbers the body needs to keep their numbers constant, they can become hyperactive and damage joint and kidney tissues.
5. How much sun you get may influence how long you will live with lupus.
Our skin makes vitamin D in response to the UV-B rays of sunlight, and vitamin D helps regulate the immune system. Getting too much sun so that the skin makes too much vitamin D, however, may be a major risk factor in the progression of lupus. Researchers have found that people who have lupus who live in sunny climates die sooner than people who have lupus who live in northerly, cloudier, colder climates, possibly because of excessive exposure to the sun leading to excessive production of vitamin D. Don't take high doses of vitamin D, and limit your exposure to the sun to 20 minutes per day if you have lupus.