A comparison between Tehran and Damavand recall rates

Following screening of newborns for congenital hypothyroidism (CH) in Tehran for 49 months and in Damavand for 21 months, a question was raised as to whether there are any differences between the recall rates and CH incidences in metropolitan and district populations. The present study was conducted to address the aforementioned issue. From February 1998 to March 2002, cord blood spot samples from 8 hospitals and a rural birth center in Tehran (the capital) and Damavand (district) were collected and tested for TSH measurement using a two site IRMA method. TSH values  20 mU/L were recalled. The diagnosis of CH was confirmed using age-adjusted reference values for serum TSH and T4 levels. The frequency distribution of recalls and CH cases in Tehran and Damavand were compared using 2 and Fisher’s exact tests, respectively. Of 30085 (Tehran: 28001 and Damavand: 2084) screened neonates, 319 (Tehran: 297 and Damavand: 22) had cord TSH values  20 mU/L. The recall rate was 1. 06% (Tehran: 1. 06% and Damavand: 1. 06%). Thirtyـtwo (Tehran: 30 and Damavand: 2) neonates had CH. The CH incidence was 1 in every 940, 933, and 1042 live births in total, Tehran, and Damavand populations, respectively. A total of 5119 out of 18260 (28%) neonates had parental consanguinity. This was 4582 out of 16178 (28. 3%) in Tehran and 537 out of 2082 (25. 8%) in Damavand. The recall rates and CH incidences were not significantly different in Tehran and Damavand. Preliminary findings of CH screening program showed that recall and CH occurrence do not have significantly different distributions in Tehran and Damavand and CH was prevalent in both regions. It could be concluded that CH might be prevalent in other parts of the country.