URBAN-RURAL DIFFERENCES IN CANCER INCIDENCE IN THE NETHERLANDS, 1989-1991

Background. Differences in cancer incidence have been observed between urban and rural communities for many decades. These differences have been attributed for the most part to lifestyle aspects. In Western pop ulations, however, differences in lifestyle have diminished. This stud y addressed the question: For which cancer sites can differences in ca ncer occurrence still be demonstrated between urban and rural communit ies in the Netherlands? Methods. Cancer incidence data from 1989 to 19 91 inclusive, were obtained from the Netherlands Cancer Registry. Age- adjusted, site-specific incidence rates were calculated for five class es of municipalities classified by address density. Results. With incr easing urbanization, slightly higher incidence rates were observed for all cancer sites combined (rate ratio [RR] = 1.08 in males and 1.12 i n females). Statistically significant RR of >1.4 were observed for Kap osi's sarcoma (m), mesothelioma (m), cancer of the liver (m), mouth/ph arynx (m + f), oesophagus (f), larynx (f), lung (f), other respiratory organs (f), cervix (f) and Hodgkin's disease (m). Significantly lower incidence rates were found in urban areas for nonmelanoma skin (m + f ) and lip cancer (m). Conclusions. In males, the urban excess of tobac co-related cancer has largely disappeared. However, urban-rural differ ences in cancer incidence still exist for other cancer sites and for t obacco-related cancer in females. Apparently, differences in the preva lence of lifestyle factors are still large enough to cause variation i n cancer incidence.