Spatial and temporal clustering of isolated cleft lip with or without cleft palate in Poland

<div><p><i>Background</i>: Geographic variation in the prevalence of isolated cleft lip with or without cleft palate may be due to exogenous environmental factors or genetic variation. In this study, we aim to evaluate the prevalence of isolated cleft lip with or without cleft palate in Polish urban and rural environments in order to identify geographic areas with high prevalence (defect clusters). <i>Methods</i>: We use all cases of congenital malformations reported to the Polish Registry of Congenital Malformations in the years 1998–2008 from the total population of 2,362,502 births. <i>Results</i>: We detect a strong signal of increased prevalence of isolated cleft lip with or without cleft palate in a single region of Poland, the Dolnośląskie voivodeship. Furthermore, we demonstrate a statistically significant prevalence differences between the urban and rural areas within this region. Through our comprehensive spatiotemporal analysis, we precisely define the cluster of the highest risk that comprises the eastern part of this voivodeship.</p></div