Spatial Distribution of Congenital Hypothyroidism

Background: This study was designed and conducted to investigate the spatial distribution of permanent and temporary congenital hyperthyroidism (PCH and TCH) in Isfahan. Methods: This study was conducted on neonates who were born from March 21, 2006 to March 20, 2011 and had undergone the congenital hypothyroidism (CH) screening program in counties affiliated to the Isfahan University of Medical Sciences. CH was diagnosed in 958 patients who treated with levothyroxine. The incidence rates of permanent and temporary congenital hypothyroidism in Isfahan province were calculated and their distribution was shown on the map. The space maps were drawn using the ArcGIS software version 9.3. Results: Based on the data obtained from the screening program, the average incidence of congenital hypothyroidism in the province during the period of 2006-2011 was 2.40 infants per 1000 live births (including both PCH and TCH). The most common occurrence was in Ardestan County (10:1000) and the lowest overall incidence was observed in the Fereydounshahr county (1.39:1000). The incidence of PCH in the counties of Ardestan and Golpayegan had the highest rate in all years of study; and the greatest number of TCH cases in the five years were observed in Nain, Natanz, Khansar and Chadegan counties. Conclusion: Adding the time dimension and performing spatial-temporal analysis is suggested because of the following items: high prevalence of CH in Isfahan province, the important role of this disease in mental retardation and neuropsychiatric disorder, the necessity of conducting future medical researches to find possible factors of CH etiology in Isfahan province, as well as necessity of performing spatial analysis with advanced statistical methods.