Opium and bladder cancer: A systematic review and meta-analysis of the odds ratios for opium use and the risk of bladder cancer Afshari, Mahdi ; Janbabaei, Ghasem ; Bahrami, Mohammad Amin ; Moosazadeh, Mahmood Abstract Publication: PLoS ONE Pub Date: June 2017 DOI: 10.1371/journal.pone.0178527 Bibcode: 2017PLoSO..1278527A