Changes in the incidence and etiology of congenital hypothyroidism detected during 30years of a screening program in central Serbia.

Abstract

The overall incidence of CH in Central Serbia during study period nearly tripled, with a significant increase in almost all etiological categories, and was associated with lowering TSH cutoffs as well as other yet unidentified factors. Further studies are needed to identify other factors associated with increasing incidence of CH. Congenital hypothyroidism (CH) is the main cause of preventable mental retardation. Recent reports have indicated a progressive increase in the incidence of primary CH throughout the world, partially explained by lowering of the TSH cutoff values. During the study period associated with lowering of the TSH cutoffs, the overall incidence of CH in Serbia tripled, including transient CH, ectopy, and dyshormonogenesis, while prevalence of athyreosis remained stable during 30 years. Significant increase in the incidence of both permanent and transient CH was observed, associated with lowering of TSH cutoffs as well as other yet unidentified factors.