title: Metabolic abnormalities and risk for colorectal cancer in the physicians' health study.
abstract: BACKGROUND
  Obesity and diabetes are established risk factors for colorectal cancer but have mainly been assessed independently. There are few data about whether the metabolic syndrome, which refers to a clustering of cardiovascular disease risk factors thought to be related to insulin resistance, including obesity, type 2 diabetes, hyperlipidemia, and hypertension, is associated with colorectal cancer risk.
  
  
  METHODS
  During and after the randomized trial of aspirin and beta-carotene, 22,071 healthy male physicians, initially ages 40 to 84 years, reported overweight (body mass index, >or=27 kg/m2), diabetes, elevated blood pressure (>or=130/85 mmHg or use of antihypertensive medication), hypercholesterolemia (>or=240 mg/dL or use of lipid-lowering medication), and occurrence of cancer on annual questionnaires. Adjusted relative risks (RR) and 95% confidence intervals (95% CI) for time-varying metabolic abnormalities and colorectal cancer were estimated using a multivariable proportional hazards model.
  
  
  RESULTS
  During 369,966 person-years of follow-up (median, 19 years), 494 physicians developed colorectal cancer. With aging of the cohort, the prevalence of having two or more abnormalities increased from 13% to 35%. Overweight (RR, 1.4; 95% CI, 1.1-1.7) and diabetes (RR, 1.5; 95% CI, 1.1-2.0) were associated with increased risk for colorectal cancer, whereas elevated blood pressure (RR, 1.1; 95% CI, 0.9-1.3) and hypercholesterolemia (RR, 0.9; 95% CI, 0.7-1.1) were not. This model assessing metabolic abnormalities independently was more predictive for colorectal cancer than a model based on the number of abnormalities (each additional abnormality RR, 1.16; 95% CI, 1.05-1.29).
  
  
  CONCLUSIONS
  Out of the markers of the metabolic syndrome assessed, overweight and diabetes are risk factors for colorectal cancer, whereas, in contrast to their role in cardiovascular disease, elevated blood pressure and hypercholesterolemia are not.
authors.affiliation: Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, 900 Commonwealth Avenue East, Boston, MA 02215, USA. til.sturmer@post.harvard.edu
authors.forename: Til
authors.initials: T
authors.lastname: Stürmer
authors.forename: Julie E
authors.initials: JE
authors.lastname: Buring
authors.forename: I-Min
authors.initials: IM
authors.lastname: Lee
authors.forename: J Michael
authors.initials: JM
authors.lastname: Gaziano
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Glynn
mesh_terms: D000328:Adult; D000368:Aged; D001900:Boston / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology; D015179:Colorectal Neoplasms / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology; D005500:Follow-Up Studies; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood / Q000150:complications / Q000453:epidemiology; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications* / Q000453:epidemiology; D008875:Middle Aged; D050177:Overweight; D010820:Physicians; D012307:Risk Factors; D011795:Surveys and Questionnaires