Epidemiology and risk factors of colorectal polyps.

The lifetime risk of colorectal cancer (CRC) in the Western world is around 5%. CRC commonly develops from precursor lesions termed polyps, classified as adenomatous or serrated polyps according to growth pattern. Despite the well-known connection between polyps and cancer, most polyps will never develop into CRC. For those that do, the time until CRC development is generally thought of as >10 years. This gives opportunity for interventional strategies to prevent transformation into cancer. This article aims to provide an overview of the epidemiology of and risk factors for colorectal polyps in the average risk population, and will encompass the effect of age, gender, ethnicity, smoking, obesity, alcohol, physical activity, NSAIDs and dietary factors on colorectal polyps.