Ask the Doctor Smoking and Graves'
"I quit smoking in 1994 and was diagnosed shortly thereafter with Graves' disease. A friend of mine quit smoking in May of last year and was diagnosed shortly thereafter with Graves' disease. . . any research on the connection? I know that episodes of blindness due to Graves' disease are much more prevalent among smokers, but the timing of our diagnoses and stopping smoking leaves us both with a big question." -- JF, Tujunga, CA.
Studies released in the 1990s well established that smokers are more likely than non-smokers to get Graves' disease, that patients with Graves' disease who smoke are more likely to have ophthalmopathy, and that their ophthalmopathy is more likely to be severe. Patients with Graves' disease have a 4- to 14-fold increased risk of ophthalmopathy. In one study, patients who had quit smoking before getting Graves' disease did not have worse ophthalmopathy than current smokers, even if they had smoked as many packs over their lifetime as the current smokers. While none of these studies specifically address the situation you describe, they suggest that quitting smoking reduces the risk, and that the timing of your friend's and your Graves' disease was a coincidence.