SMOKELESS AND COMBUSTIBLE TOBACCO USE AND MORTALITY: ANALYSIS FROM THE 1987 TO 2005 NATIONAL HEALTH INTERVIEW SURVEY

Introduction: Few prospective studies have examined mortality outcomes associated with smokeless tobacco use in the US and information is limited regarding the risks associated with former and current exclusive smokeless tobacco users compared to combustible tobacco smoking and dual use. Objective: To investigate associations of smoking and smokeless tobacco use with all-cause, cancer, cardiovascular disease, and chronic lower respiratory disease mortality in US adults. Methods: We studied 127,995 adults, 18 years of age or older, who participated in the National Health Interview Survey 1987, 1992, 1998, 2000 and 2005 Cancer Control Supplement and were followed for mortality through December 2011. Information on history of combustible tobacco (cigarettes, pipes or cigars) smoking and smokeless tobacco (SLT: chewing tobacco or snuff) use was assessed at baseline. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for mortality outcomes comparing former and current SLT users, former and current smokers and current dual users to never tobacco users. Results: 51% of participants were never tobacco users, 1% former SLT users, 1% current SLT users, 22% former smokers, 25% current smokers and 1% current dual users. After a median follow-up time of 12 years, there were 23,405 deaths. After multivariable adjustment, the risk for all-cause mortality was higher for combustible tobacco users compared to never users (HR [95% CI] were 1.29 [1.25-1.34], 1.85 [1.78-1.93] and 1.69 [1.48-1.94] for former smokers, current smokers and current dual users respectively). The risk for death during follow-up time for exclusive SLT users was not significantly different from never users (HR [95% CI]: 0.93 [0.76-1.14] for former SLT users and 0.95 [0.80-1.12] for current SLT users). Conclusions: Compared to never tobacco users, combustible tobacco users had higher risk in all-cause, cancer, cardiovascular disease, and chronic lower respiratory disease mortality. Exclusive smokeless tobacco users did not have higher risk than never tobacco users. These results suggest that using smokeless tobacco as a replacement for combustible tobacco smoking may reduce mortality for adults with a history of smoking