Cancer Epidemiology 33 (2009) 424–430 Contents lists available at ScienceDirect Cancer Epidemiology The International Journal of Cancer Epidemiology, Detection, and Prevention journal homepage: www.cancerepidemiology.net Tobacco use, body mass and cancer mortality in Mumbai Cohort Study Mangesh S Pednekar a,*, James R He´bert a,b,c, Prakash C Gupta a,c a Healis-Sekhsaria Institute for Public Health, CBD Belapur, Navi Mumbai, India South Carolina Statewide Cancer Prevention & Control Program, University of South Carolina, Columbia, SC, United States c Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, United States b A R T I C L E I N F O A B S T R A C T Article history: Accepted 24 September 2009 Background: Tobacco use and body mass are major risk factors for many cancers Despite this, very little is known about their combined effect on cancer mortality These relationships are virtually unexplored in populations having patterns of both tobacco use and body habitus atypical of those typically enrolled in epidemiologic studies Methods: A prospective cohort study of 148,173 men and women aged !35 years was conducted in Mumbai, India Subjects were recruited during 1991–1997, measured for a variety of risk factors, including tobacco use and anthropometry, and then followed for approximately 5– years Results: During 774,129 person-years of follow up, a total of 796 cancer deaths were observed Tobacco use, especially smoking in men, was associated with particularly high risk of death in extreme categories of body mass At highest risk were underweight smoking males [hazard ratio (HR) = 9.45, 5.87, and 5.75 for those smokers who were extremely thin (