Cigarette smokers also are more likely to develop thyroid eye complications of Graves' disease, and treatments for those eye problems are less effective in smokers. So, in addition to all the other health problems related to smoking, you can add increased risk and worsening of thyroid disease.
For more info on the connections, check out Smoking and Thyroid Disease.
And just in case you think I'm not sympathetic, I am! I was a smoker from 17 to 30, and quitting was one of the HARDEST things I've ever done. But I did it, and I'm glad I did! Read How I Quit Smoking. And don't forget to drop by About's site to help you stop smoking.