Epidemiological analysis of the incidence of cleft lip and palate in relation to the radon concentration in the German Democratic Republic from 1980 to 1989.

PURPOSE: Cleft lip and palate (CLP) can be attributed aetiologically to genetic and exogenous influences. A significant teratogenic potency is attributed to ionising radiation. In Germany, radon is the element most strongly involved in radiation levels on the earth's surface, although there are considerable geographical differences due to geological characteristics and mining. A correlation between regional radon concentrations and the incidence of cleft malformations and even abortions has not yet been systematically investigated. MATERIAL AND METHODS: With the introduction of mandatory reporting of CLP (1967), a centralised register was available which depicts the incidences in the 15 districts of the German Democratic Republic (GDR) with their associated counties for the years. The time interval from 1980 to 1989 was analysed. The numbers of live births and stillbirths were obtained from the statistical yearbooks; the radon concentrations in the soil were sourced from the German Federal Office for Radiation Protection. RESULTS: The birth rate decreased significantly with increasing radon exposure in the soil (r = -0.400; p < 0.001). At the same time, there was a statistically significant correlation between higher radon exposure and the number of cleft births (r = 0.068; p = 0.003). In addition, the number of stillbirths increased with higher radiation exposure (p < 0.001). CONCLUSION: The study identified correlations between radon exposure in the soil and fertility. The results confirmed the suspected teratogenic and abortive potential of regionally elevated radon exposure.