Injection with iodine contrast may raise risk of thyroid disorders.

Bloomberg News (1/24, Ostrow) reports, "Chemicals used to enhance pictures obtained from medical imaging tests may lead to overactive or underactive thyroid glands, a study showed. Patients injected with contrast material were about twice as likely as those who didn't get the chemical to develop hyperthyroidism, when the gland produces too much thyroid hormone and can cause rapid or irregular heart rates, according to a study today in the Archives of Internal Medicine. Results also showed an increased risk for hypothyroidism."

        The New York Times (1/24, O'Connor) "Well" blog notes, "Iodide, a form of the chemical element iodine, is widely used as a radiocontrast agent to allow doctors to see blood vessels and tissues in medical imaging tests. In a typical year, about 80 million doses of iodinated contrast agents are administered worldwide, largely for CT scans, cardiac catheterizations and other angiograms." The blog also notes that this study "examined data on" about 2,000 patients "who were treated at Boston-area hospitals for various conditions and followed over a 20-year period."

        Medscape (1/24, Keller) details, "Researchers found a statistically significant association between ICM exposure and incident hyperthyroidism (odds ratio [OR], 1.98; 95% confidence interval [CI], 1.08 - 3.60; P = .03), but not incident hypothyroidism (OR, 1.58; 95% CI, 0.95 - 2.62; P = .08)." A commentary noted "that the study was conducted in the Boston area, which has sufficient dietary iodine intake, so the results may not be generalizable to parts of the world with insufficient intake."