Is opium a real risk factor for esophageal cancer or just a methodological artifact? Hospital and neighborhood controls in case-control studies.

<h4>Background</h4>Control selection is a major challenge in epidemiologic case-control studies. The aim of our study was to evaluate using hospital versus neighborhood control groups in studying risk factors of esophageal squamous cell carcinoma (ESCC).<h4>Methodology/principal fi...

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Bibliographic Details
Main Authors: Ramin Shakeri, Farin Kamangar, Dariush Nasrollahzadeh, Mehdi Nouraie, Hooman Khademi, Arash Etemadi, Farhad Islami, Hajiamin Marjani, Saman Fahimi, Alireza Sepehr, Atieh Rahmati, Christian C Abnet, Sanford M Dawsey, Paul Brennan, Paolo Boffetta, Reza Malekzadeh, Reza Majdzadeh
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22396792/pdf/?tool=EBI