title: Calcium-channel blockers and risk of cancer.
abstract: BACKGROUND
  Previous studies have been interpreted as suggesting an increase in risk of cancer among users of calcium-channel blockers compared with users of beta-blockers. To explore this issue further, we studied a large group of hypertensive patients to investigate the relation of calcium-channel blockers and cancer.
  
  
  METHODS
  In cohorts of users of calcium-channel blockers, angiotensin-converting-enzyme (ACE) inhibitors, and beta-blockers, we identified all cases of cancer diagnosed in 1995. We used a nested case-control analysis to estimate the risk of cancer among users of calcium-channel blockers and ACE inhibitors, with users of beta-blockers as a reference group. The study was based on information taken from the General Practice Research Database, and the study population was restricted to patients with at least 4 years of medical history recorded on computer.
  
  
  RESULTS
  The study was based on 446 cases of cancer and 1750 controls. The relative risk estimates for all cancers combined were 1.27 (95% CI 0.98-1.63) and 0.79 (0.58-1.06) for users of calcium-channel blockers and ACE inhibitors, respectively, relative to users of beta-blockers. There was little difference in risk estimates with duration of use of calcium-channel blockers of less than 1.0 year (relative risk 1.46), 1.0-3.9 years (1.26), and 4.0 years or more (1.23).
  
  
  CONCLUSIONS
  The small positive association between calcium-channel blockers and risk of cancer is unlikely to be causal since there is no increase in risk with increasing duration of calcium-channel blocker use.
authors.affiliation: Boston Collaborative Drug Surveillance Program, Boston University Medical Center, Lexington, MA 01273-5207, USA.
authors.forename: H
authors.initials: H
authors.lastname: Jick
authors.forename: S
authors.initials: S
authors.lastname: Jick
authors.forename: L E
authors.initials: LE
authors.lastname: Derby
authors.forename: C
authors.initials: C
authors.lastname: Vasilakis
authors.forename: M W
authors.initials: MW
authors.lastname: Myers
authors.forename: C R
authors.initials: CR
authors.lastname: Meier
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000009:adverse effects / Q000627:therapeutic use; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects / Q000627:therapeutic use; D002121:Calcium Channel Blockers / Q000009:adverse effects* / Q000627:therapeutic use; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008297:Male; D009369:Neoplasms / Q000139:chemically induced*; D012306:Risk; D011795:Surveys and Questionnaires; D006113:United Kingdom
chemical_list: D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D002121:Calcium Channel Blockers