Geoepidemiology of hepatocellular carcinoma in the island of Crete, Greece. A possible role of pesticides.

Abstract

Geoepidemiological data of hepatocellular carcinoma (HCC) are lacking. Crete has a genetically homogeneous population and is suitable for studies to identify a possible contribution of environmental factors in HCC. Databases for HCC (316 cases), hepatitis B virus (HBV) (633) and hepatitis C virus (HCV) (392), constructed over the past 20 years in our Unit, were used. Data included place of birth and place of residence for the last 15 years. Hellenic Statistical Authority provided population statistics from 1980 to 2014. Time-spatial methods were applied in Gis-ArcMap 10 software. Spatial autocorrelation tests (Moran's index) detected differences between the spatial distribution to place of residence. Spatial density maps were created. Kriging Interpolation was applied, to produce prediction maps of HCC. Hepatitis C virus appears in areas of high prevalence while HBV is uniformly distributed. HCC is more prevalent in Eastern Crete. A spatial autocorrelation between HCC and either HCV (Moran's I = 0.88, P < 0.001) or HBV (I = 0.84, P < 0.02) was found as expected. However, there is a discrepancy in the South East of Crete, where a higher prevalence of HCC than expected was observed. This is an area where extensive use of pesticides in large green houses is practiced. Hepatocellular carcinoma is associated with the dispersion of HCV and HBVs. In an area with widespread use of pesticides, a higher than expected spatial distribution of HCC was detected.