Risk of Several Cancers is Higher in Urban Areas after Adjusting for Socioeconomic Status. Results from a Two-Country Population-Based Study of 18 Common Cancers

Abstract

Some studies suggest that there are urban-rural variations in cancer incidence but whether these simply reflect urban-rural socioeconomic variation is unclear. We investigated whether there were urban-rural variations in the incidence of 18 cancers, after adjusting for socioeconomic status. Cancers diagnosed between 1995 and 2007 were extracted from the population-based National Cancer Registry Ireland and Northern Ireland Cancer Registry and categorised by urban-rural status, based on population density of area of residence at diagnosis (rural <1 person per hectare, intermediate 1-15 people per hectare, urban >15 people per hectare). Relative risks (RR) were calculated by negative binomial regression, adjusting for age, country and three area-based markers of socioeconomic status. Risks were significantly higher in both sexes in urban than rural residents with head and neck (males RR urban vs. rural = 1.53, 95 % CI 1.42-1.64; females RR = 1.29, 95 % CI 1.15-1.45), esophageal (males 1.21, 1.11-1.31; females 1.21, 1.08-1.35), stomach (males 1.36, 1.27-1.46; females 1.19, 1.08-1.30), colorectal (males 1.14, 1.09-1.18; females 1.04, 1.00-1.09), lung (males 1.54, 1.47-1.61; females 1.74, 1.65-1.84), non-melanoma skin (males 1.13, 1.10-1.17; females 1.23, 1.19-1.27) and bladder (males 1.30, 1.21-1.39; females 1.31, 1.17-1.46) cancers. Risks of breast, cervical, kidney and brain cancer were significantly higher in females in urban areas. Prostate cancer risk was higher in rural areas (0.94, 0.90-0.97). Other cancers showed no significant urban-rural differences. After adjusting for socioeconomic variation, urban-rural differences were evident for 12 of 18 cancers. Variations in healthcare utilization and known risk factors likely explain some of the observed associations. Explanations for others are unclear and, in the interests of equity, warrant further investigation.

Does the Prevalence of Skin Cancer Differ by Metropolitan Status for Males and Females in the United States?

“…The results of adjusted analysis indicated that skin cancer was significantly related to metropolitan status. Our findings conflict with other studies that did not find a significant relationship between any defined metropolitan status and skin cancer [6,8,9,11] and those that found a significant relationship between skin cancer and living in rural versus nonrural areas [9]. The results of this study found a significant relationship between skin cancer and suburban versus rural areas as well as suburban versus urban areas.…”

“…Some studies found a positive relationship between skin cancer incidence and population density, while others did not [9]. Numerous European studies have shown individuals living in urban regions have an increased incidence of skin cancer compared to individuals living in rural regions [6,10,11]. However, a study conducted in the United States suggested metropolitan status was not significantly related to incidence of invasive cutaneous melanoma [8].…”

Prostate cancer screening in Switzerland: 20-year trends and socioeconomic disparities

“…This has been found in some (Baade et al, 2011;Coory and Baade, 2005) but not all (Sharp et al, 2014;Weber et al, 2013) previous studies. Geographical differences in PCa exams could potentially be explained by area-level variations in access to health services; urban area being really dense in health services in Switzerland (Berlin et al, 2014).…”

“…Geographical differences in PCa exams could potentially be explained by area-level variations in access to health services; urban area being really dense in health services in Switzerland (Berlin et al, 2014). Also, differences in cancer beliefs, attitudes and help-seeking behavior between urban and rural residents have been reported (Sharp et al, 2014). …”

Lifetime excess cancer risk due to carcinogens in food and beverages: Urban versus rural differences in Canada

“…6 Other urban-rural health differences show certain cancers (stomach and lung) have a higher rate of incidence for rural inhabitants; whereas, breast cancer and heart disease are more prevalent for urbanites. 7,8 The objective of this paper is to conduct preliminary probabilistic modelling of intake for selected known (arsenic, benzene, polychlorinated biphenyls (PCBs)) or suspected (lead, tetrachloroethylene (PERC)) carcinogens, as classified by the International Agency for Research on Cancer, 9 that have been detected in North American foods, with a specific focus on differences between Canadians living in urban versus rural areas.…”