A new study from the University of Michigan School of Medicine and Public Health finds that mercury ingested through eating seafood may increase the risk of autoimmune disorders, with women of childbearing age at greater risk. In the new study, study leader Associate Professor Emily Summers and her colleagues analyzed data from the 1999-2004 U.S. National Health and Nutrition Examination Survey (NHANES) involving female participants aged 16 to 49. The results found that exposure to mercury is a major risk factor for autoimmune diseases. The more mercury exposure, the more autoantibodies and the greater the risk of autoimmune disease. The study found that fish such as swordfish, mackerel and squareheads contained the highest levels of mercury, while shrimp, canned light tuna and salmon contained relatively low levels of mercury. Seafood is rich in a number of key nutrients and has a variety of health benefits. But to prevent autoimmune diseases, women of childbearing age are better off choosing seafood with lower levels of mercury. Autoimmune diseases, which cause the body’s immune system to mistakenly attack healthy cells, affect more women than men, Summers said. Such diseases include inflammatory bowel disease, lupus erythematosus, dry syndrome, rheumatoid arthritis and multiple sclerosis. Autoimmune diseases are among the top 10 causes of death in women. Analysis of environmental factors can help to better understand the etiology of autoimmune diseases beyond genetics, which in turn can lead to better symptomatic treatment.