Mortality among male smokers and smokeless tobacco users in the USA

Abstract

Background: One published study simultaneously reported the mortality associated with cigarette smoking and smokeless tobacco (ST) use in the USA. In this study, we focus only on men ages 40-79 years old and extend the follow-up by 4 years. Methods: We used selected years (1987-2010) of National Health Interview Survey (NHIS) Linked Mortality Files to classify 46,104 men age 40-79 years with respect to 7 categories of smoking and/or ST use. We used Cox proportional hazards models adjusted for age, race/ethnicity, marital status, education, income, health status, body mass index, and region to estimate hazard ratios (HRs; 95% confidence intervals, CI) for mortality from all causes, heart diseases, malignant neoplasms, and two mutually exclusive categories: smoking-related and other diseases. Results: There were 15,540 deaths from all causes, including 3476 never tobacco users, 4782 exclusive smokers, and 210 exclusive ST users. The latter had significant excess mortality from all causes (HR = 1.25, CI = 1.08-1.46), but not from heart diseases (HR = 1.16, CI = 0.85-1.59), malignant neoplasms (HR = 1.17, CI = 0.83-1.67), and all smoking-related diseases (HR = 1.19, CI = 0.97-1.46). However, they had higher mortality for all other causes (1.39, CI = 1.10-1.74), which was largely seen in age 40-59 years (HR = 1.68, CI = 1.11-2.54). Current smokers, with or without ST use, also had significantly elevated HRs for other causes (1.70 and 1.57, respectively), in addition to significant increases in mortality from heart diseases (1.98 and 2.00), malignant neoplasms (2.60 and 2.84), and all smoking-related diseases (2.32 and 2.47). Conclusions: This is the first simultaneous mortality follow-up study of older American male smokers and ST users. ST users did not have excess mortality from any smoking-related diseases, but younger users had an elevation in deaths from other causes.