Another reason not to smoke. A study links smoking with Graves' disease:

Women who smoke are twice as likely to develop an overactive thyroid caused by Graves' disease, a study shows.

Researchers say the results suggest that cigarette smoking should be considered a major risk factor for the mysterious disorder.

Graves' disease is a common cause of an overactive thyroid (known as hyperthyroidism), but researchers say little is known about what risk factors are associated with the disease. It affects up to one in 1,000 women.

(Warner, "Cigarette Smoking Linked to Overactive Thyroid", WebMD, Jul.26)