Geographical Inequalities in Mortality and Incidence in Larynx Cancer in Men: Socioeconomic and Environmental Factors

Abstract

Background: Several studies suggest the relationship between lower socioeconomic status and environmental factors with increased risk of cancer. Within the framework of the MEDEA project, this work aims to identify geographic inequalities in larynx cancer (LC) mortality and incidence in men and its association with deprivation and environmental factors. Methods: Ecological study having as reference population men living in the city of Zaragoza. The study period was 1996-2003. The deaths were obtained from the Mortality Registry of Aragon, the incident cases from the Cancer Registry of Zaragoza and the socioeconomic data from the 2001 Census. We used the European Pollutant Emission Register database to locate possible polluting industries. For each census tract (CT) a deprivation index was obtained using principal components analysis. Smoothed Standardized Mortality and Incidence ratios were also calculated using Bayesian methods. Results:We analysed 211 deaths and 569 incident cases with CT, corresponding to 95% of the total registered mortality cases and 97.8% incidence. The CTs in the highest quartile, highest deprivation index, had significantly higuer risk of mortality (2.74 times) as well as incidence (1.66 times) by LC. However, the environmental indicators have not been shown a statistically significance association. Conclusions: The CTs with the lowest socioeconomic status have higher risk of LC mortality and incidence. Nevertheless, the possible exposition to the polluting industrial focus does not explain the observed geographic variability.