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RAI fails to increase atherosclerosis markers
Among patients treated with radioactive iodine for benign thyroid disease, no changes were found in carotid intima-media thickness in short-term follow-up or in plaque presence longer term, study data show.
Jeppe Lerche la Cour, MD, of the department of clinical physiology at the University of Copenhagen in Denmark, and colleagues evaluated patients treated for benign thyroid disorders to determine whether atherosclerosis develops early or late after radioactive iodine (RAI) therapy in benign thyroid disease. Carotid intima-media thickness was assessed by ultrasound in 39 patients before treatment and at 1, 3, 6 and 12 months after treatment to evaluate early changes associated with RAI. Late changes were evaluated by a cross-sectional case-control comparison of plaque presence in 193 patients treated with RAI (cases; mean follow-up, 9.8 years) and 95 patients treated with surgery (controls; mean follow-up, 5.6 years).
No significant changes in carotid intima-media thickness after RAI were found among the group studied for early damage; mean carotid intima-media thickness was 0.73 mm before treatment and 0.73 mm 12 months after treatment. No cerebrovascular events occurred during follow-up.
In the group studied for late changes, no significant differences in mean carotid intima-media thickness or presence of plaques were found between the groups in multivariate analyses. Age (P < .001), smoking status (P = .02) and known hypothyroidism at the time of the examination (P = .01) affected carotid intima-media thickness. Plaque presence was related to age (P < .001), smoking status (P < .001), LDL cholesterol (P = .003), systolic blood pressure (P = .005), known diabetes (P < .001), sex (P = .001), BMI (P = .02) and an interaction between sex and BMI (P = .004).
“Our findings offer no explanation as to why epidemiological data indicate an increased risk of cerebrovascular events after RAI therapy,” the researchers wrote. “Further studies may, thus, be needed to clarify whether radiation induced atherosclerosis in part of the mechanism.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.