title: Hospital visitors as controls.
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Health Sciences, American University of Beirut, Lebanon.
authors.forename: H K
authors.initials: HK
authors.lastname: Armenian
authors.forename: N G
authors.initials: NG
authors.lastname: Lakkis
authors.forename: A M
authors.initials: AM
authors.lastname: Sibai
authors.forename: S S
authors.initials: SS
authors.lastname: Halabi
mesh_terms: D001943:Breast Neoplasms; D003327:Coronary Disease; D006801:Humans; D007861:Lebanon; D011897:Random Allocation; D012494:Sampling Studies; D014789:Visitors to Patients