Introduction Our objective is to study the relation between industrial pollution and cancer in Spain by defining a simple industrialisation index (town level), using the information from the European Pollutant Release and Transfer Register (E-PRTR).

Materials and Methods We used data on industries from the PRTR-Spain for year 2007. We selected the 3458 facilities with positively validated co-ordinates. For the 8098 Spanish towns we defined the index as a factor with four levels based on the number of factories in a radius of 2.5 km from the centroid of each town: Value 0 for towns with no factory within the radius; 1 for those with 1 factory; 2 for those with 2, 3 or 4; and 3 for those with more than four factories. The index, along with socio-demographic indicators (potential confounders), was included in a spatial Poisson model (BYM) to estimate the cancer mortality risk associated with the index levels. We fitted models for 33 cancer causes. Also trend tests were computed.

Results Many causes, 19, showed statistical association with at least one level of the factor. Almost all tumours related to the digestive system and the respiratory system showed excess of risk and/or trend linked with the index.

Conclusions The proposed index is a useful tool to explore possible associations between the level of industrialisation of residential areas and its health outcomes, despite of its limitations. Digestive and respiratory system tumours could be associated to residence near to industrial areas.