ABSTRACT
BACKGROUND: Iodized salt was reintroduced in Iran in 1989. Just before distribution of iodized salt, thyrotoxicosis was observed in 3.7% of the patients with atrial fibrillation (AF) in university teaching hospitals in Isfahan, a centrally located city in Iran. As repletion of iodine may increase the rate of autoimmune thyroid diseases and toxic multinodular goiter, this study was designed to evaluate the rate of thyrotoxicosis in patients with AF in the same hospitals after about a decade of iodized salt consumption. METHODS: In a case-control study with convenience sampling, 100 patients with AF and an equal number of age- and sex-matched subjects taking the same medications were selected as case and control groups, respectively, in university hospitals in 1997. RESULTS: Eight percent of patients with atrial fibrillation had overt thyrotoxicosis versus one percent in the control group (odds ratio=8.6, 95% CI = 6.5 to 10.7, P<0.02). Thyrotoxicosis in patients with AF was 8 times higher than in the control group without AF. In comparison with the period before use of iodized salt, AF more than doubled (8% vs. 3.7%). CONCLUSION: Thyroid function should be evaluated in all patients older than 40 years of age with AF. The benefits of iodine supplementation are great, but more attention should be paid to the complications of iodine repletion, including thyrotoxicosis and its frequent accompaniment, AF.
Subject(s)
Atrial Fibrillation/epidemiology , Iodine/therapeutic use , Sodium Chloride, Dietary/therapeutic use , Thyrotoxicosis/epidemiology , Thyrotoxicosis/prevention & control , Adult , Age Distribution , Aged , Case-Control Studies , Comorbidity , Female , Humans , Hyperthyroidism/epidemiology , Hypothyroidism/epidemiology , Incidence , Iodine/deficiency , Iran/epidemiology , Male , Middle Aged , Thyrotoxicosis/drug therapyABSTRACT
AIMS: To evaluate the prevalence of congenital hypothyroidism (CH) in a screening program performed for the first time in Isfahan, Iran. METHODS: From May 2002 to December 2002, T4 and TSH serum concentrations of 20,000 3- to 7-day-old newborns, born in all 17 hospitals of the city, were measured by radioimmunoassay and immunoradiometric assay, respectively. The newborns with abnormal screening results (TSH >20 mIU/l, T4 <6.5 microg/dl and based on the weight) were re-examined. RESULTS: Of 531 recalled subjects (recall rate 2.6%), 54 were confirmed to be hypothyroid, showing a prevalence of 1:370 for CH. CONCLUSION: Considering the high frequency of CH, the necessity of implementing a routine screening program in the healthcare system of Isfahan Province is emphasized.
