Association of Urbanization Levels and Colorectal Cancer Incidence in Iran

Urbanization increases the risk of non-communicable diseases including colorectal cancer by creating changes in lifestyle. We seek, in this study, to create urbanization levels based on various factors affecting urbanization and to investigate its relationship with the colorectal cancer incidence in Iran. Using information from census 2011, we collected data on 33 indicators related to urbanization in 31 provinces in Iran. To rank the provinces, we used density-based hierarchical clustering scheme. In order to determine similarities or differences between the provinces, we used the square of the Euclidean distance dissimilarity coefficient; Ward’s algorithm was used to merge the provinces to minimize intra-cluster variance. The data obtained from the National Cancer Registry System in 2009 were used to determine the colorectal cancer incidence rate in Iran. One-way ANOVA was used to investigate the association between colorectal cancer incidence and urbanization levels. All statistical analyses were performed, using SPSS (Version 23) software. Using clustering method, the researchers divided the provinces into 4 different urbanization levels. The results of the ANOVA test indicates a correlation between colorectal cancer incidence and urbanization levels, with a level of significance (P = 0.001) for both genders, (P = 0.001), for men, and (P = 0.002) for women. The findings indicate a difference between the 1st and 4th levels as well as between the 2nd and 4th levels. The results of this study showed that considering the lifestyle of people living in higher urban areas, which includes low activity and the use of fast and processed foods, we may claim that residents of these areas are more exposed to the risk factors of this cancer. On the other hand, a higher level of awareness of the residents of these areas and their greater access to health facilities contribute to their further admissions for screening, which can lead to an increase in the number of identified cases of the disease in these areas.