Scientists at the University of Michigan have discovered that the mercury in some seafood may be associated with autoimmune disease, especially in women of childbearing age.  It's long been known that autoimmune diseases are caused by exposure to environmental triggers in people with genes that confer susceptibility to autoimmune disese.

The researchers pointed out that relatively high amounts of mercury are found in swordfish, king mackerel and tile fish. Lower amounts are found in shrimp, canned light tuna and salmon. In addition, the higher the exposure to mercury, the higher levels of autoantibodies in individuals with autoimmune disorders. While the presence of autoantibodies confers autoimmunity and not necessarily autoimmune disease, autoantibodies are primarily responsible for symptoms when autoimmunity escalates to autoimmune disease.

Source: Alan Mozes, "Mercury in Seafood May Raise Risk of Autoimmune Diseases in Women:Study." www.philly.com, Feb 12, 2015