Tobacco use and cancer survival: a cohort study of 40,230 Swedish male construction workers with incident cancer.

On theoretical grounds, nicotine has been implicated as a modifier of cancer progression. We investigated possible associations of smoking or use of Scandinavian moist snuff (snus) with survival after cancer among Swedish male construction workers. Snus use is associated with substantial exposure to nicotine but not to the combustion products in smoke. Among 336,381 workers with detailed information on tobacco use in 1971-1992, we observed 40,230 incident cancers. Complete follow-up through 2007 was accomplished through linkage to population and health registers. Hazard ratios (HRs) and 95% confidence intervals (CIs) for death from any cause, cancer-specific death and death from other causes were derived from Cox proportional hazards regression models adjusted for age at diagnosis, body mass index at study entry and period of diagnosis. Never users of any tobacco served as reference. Increased risks of cancer-specific death were observed both among exclusive smokers (HR(all cancer) 1.15, 95% CI: 1.10-1.21) and never-smoking snus users (1.15, 95% CI: 1.05-1.26). As regards deaths due to other causes, exclusive smokers had higher relative risks than exclusive snus users (p = 0.03). A history of tobacco use, even exclusive use of the seemingly benign snus, is associated with moderately increased cancer-specific mortality. Although nicotine might play a role, the mechanisms warrant further investigation.