title: Obesity and Colorectal Cancer.
abstract: There is strong evidence that modifiable lifestyle factors such as obesity play a key role in colorectal carcinogenesis. Epidemiologic data have consistently reported a positive association between obesity and colorectal cancer. The relative risk associated with general obesity (as assessed by BMI) is higher in men than in women and for cancer of the colon than for cancer of the rectum. Abdominal obesity (as assessed by waist circumference (WC) or waist-to-hip ratio) is associated with an increased risk of colorectal cancer in both sexes, with stronger associations for cancer of the colon than for cancer of the rectum. Plausible biological mechanisms include insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines and steroid hormones. In addition to its effect on colorectal cancer incidence, obesity may play a role in colorectal cancer recurrence, treatment outcomes and survival. Understanding the effects of childhood and adolescent obesity and weight change over the life course in relation to future risk of colorectal cancer is incomplete but essential for targeted preventive recommendations. This chapter summarizes the current evidence on the relationship between obesity and colorectal cancer and colorectal adenoma, a common precursor lesion.
authors.affiliation: Department of Epidemiology and Preventive Medicine, University of Regensburg, Regensburg, Germany.
authors.forename: Carmen
authors.initials: C
authors.lastname: Jochem
authors.affiliation: Department of Epidemiology and Preventive Medicine, University of Regensburg, Regensburg, Germany. Michael.Leitzmann@klinik.uni-regensburg.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Leitzmann
mesh_terms: D018256:Adenomatous Polyps / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D015992:Body Mass Index; D003111:Colonic Polyps / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D006801:Humans; D008019:Life Style; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D011230:Precancerous Conditions / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D015995:Prevalence; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors
keywords: Colorectal cancer; Epidemiology; Obesity