title: The possibility of unmeasured confounding variables in observational studies: a forgotten fact?
authors.forename: James Brian
authors.initials: JB
authors.lastname: Byrd
authors.forename: P Michael
authors.initials: PM
authors.lastname: Ho
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D009203:Myocardial Infarction / Q000517:prevention & control*; D016903:Drug Monitoring
chemical_list: D000959:Antihypertensive Agents