Medications and Colorectal Cancer Risk
1. To investigate the relationship between colorectal cancer risk and the use of acid suppressive medications including proton pump inhibitors and histamine receptor antagonists.
2. To investigate the relationship between colorectal cancer risk among men and women age 40 years and older and the use of cholesterol lowering agents including HMG-CoA reductase inhibitors (statins), bile-acid sequestrants, fibric acid derivatives, and niacin.
3. To investigate the relationship between colorectal cancer risk and the use of antihypertensive agents including calcium channel blockers (CCBs), beta-adrenergic blockers, angiotensin converting enzyme inhibitors (ACE inhibitors), angiotensin II receptor antagonists, and diuretics.
As secondary aims, we proposed to explore the association between colorectal cancer risk and a history of several medical conditions and medications, including: peptic ulcer disease and/or Helicobacter pylori infection; and diabetes mellitus and antidiabetic medications. We also proposed to conduct preliminary analyses examining the association between the use of Cox-2 inhibitors and colorectal cancer risk.
We conducted a case-control study among men and women age 40 years and older enrolled in Group Health Cooperative (Group Health) using automated health plan data to ascertain information on medication use and automated pharmacy data to identify medications of interest (statins, antihypertensives, acid suppressants, and diabetic medications), and potential confounders for cases and controls during the 10 years prior to reference date. Incident colorectal cancer cases diagnosed during January 1, 2000 to December 31, 2003 were identified from the western Washington Surveillance, Epidemiology, and End Results (SEER) cancer registry. A total of 665 cases were included in the study. One control was selected per case and matched on age (month/year), gender, enrollment (month/year start date), and reference date. Controls met the same exclusion requirement of cases and were required to be residing in one of 13 western Washington counties covered by the SEER registry. Group Health’s Institutional Review Board approved the study.
Risk for colorectal cancer was not associated with use of statins (odds ratio, 1.02; 95% CI, 0.65-1.59), other lipid-lowering agents (odds ratio, 1.31; 95% CI, 0.70-2.47), angiotensin-converting enzyme inhibitors (odds ratio, 0.98; 95% CI, 0.67-1.43), calcium channel blockers (odds ratio, 1.06; 95% CI, 0.72-1.55), or diuretics (odds ratio, 1.00; 95% CI, 0.70-1.44). Risk did not differ by duration of medication use, including long-term use.
Risk for colorectal cancer was not reduced by use of statins or angiotensin-converting enzyme inhibitors. Other lipid-lowering and antihypertensive medications were also not associated with colorectal cancer risk.