Is educational level associated with colorectal cancer risk?

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Existing evidence was inconclusive about whether socioeconomic status (SES) and educational inequalities influence colorectal cancer (CRC) risk, including whether lower or higher SES or education is associated with developing CRC. This study aimed to investigate the relationship between educational level and CRC.

This observational prospective cohort analysis used data from 400,510 participants in EPIC (European Prospective Investigation into Cancer and Nutrition). During a mean follow-up of 8.3 years, 2,447 participants developed CRC: 1,551 developed colon cancer and 896 developed rectal cancer.

The researchers used Cox proportional hazard regression analysis, stratified by age, gender and center and adjusted for potential confounders, to estimate hazard ratios (HR) and 95% confidence intervals (95% CI). They also estimated relative indices of inequality (RII) for education using Cox regression models. Separate analyses examined tumor location, gender and geographical region.

Compared with participants with college/university education, those with vocational secondary education or less had a lower risk of developing CRC, but this difference was not statistically significant. When the analysis was further stratified by tumor location, adjusted estimates for proximal colon cancer were statistically significant for primary education or less (HR 0.73, 95% CI 0.57–0.94) and vocational secondary education (HR 0.76, 95% CI 0.58–0.98), compared with college/university education.

The inverse association between lower education and CRC risk was particularly evident in women and Southern Europe. These associations were statistically significant for CRC, colon cancer and proximal colon cancer.

The researchers concluded that lower educational level was associated with lower CRC risk compared with higher educational level, especially for the proximal colon. This association was most pronounced in women and Southern Europe.