Deprivation level and the risk of colorectal cancer by anatomic subsite in Northern England

Evidence suggests that the incidence of many cancers including bowelcancer vary according to socioeconomic status and education. in case of colorectalcancer, the direction of this association might be even different for anatomicalsubsites. the aim of this study was to describe the variation in the incidence ofcolorectal cancer by subsites across north of england and correlate it withcommunity deprivation.methods: incidence data were obtained from a population- based cancer registryfor the period 1976-2000. small areas were characterized by their affluence orlack of it, by deriving a townsend score for each enumeration district from the 1991census. the age-standardized incidence rates were calculated for different sites ofcolorectal cancer for each fifth. the association of each fifth with incidence was alsostudied using poisson regression.results: in men, the age standardized incidence for rectal cancer ranged from 18.3(for fifth 1, most affluent) to 22.3 (for fifth 5, most deprived) but the trend forproximal cancer was reverse (9.4 for fifth 1 and 8.8 for fifth 5). poisson modelsshowed a significant inverse association between deprivation level and proximalcancer in both genders. rectal cancer had a positive significant association withdeprivation level in men (rr+1.25, 95% ci, 1.19-1.32).conclusion: the association of socioeconomic status with proximal cancer wasdifferent from that with rectal cancer. socioeconomic status is not a direct risk factorand might consider as a proxy for life style factors. this indicates that lifestylecorrelates of different subsites of bowel cancer differ. therefore, the different sitesof crc should not be combined in aetiological studies.