Key Points Question Are electronic cigarette (e-cigarette) users exposed to known tobacco-related toxicants and, if so, how does the exposure compare with that of combusted tobacco cigarettes? Findings In this population-based cohort study of 5105 participants, current exclusive e-cigarette users had greater concentrations of biomarkers of nicotine, tobacco-specific nitrosamines, volatile organic compounds, and metals compared with never tobacco users. However, these concentrations were lower than those observed in current exclusive cigarette smokers and dual users of both products. Meaning Use of e-cigarettes appears to be associated with exposure to known tobacco-related toxicants, but the exposure is reduced compared with cigarette smoking.

Imazethapyr, a heterocyclic aromatic amine, is a widely used crop herbicide first registered for use in the United States in 1989. We evaluated cancer incidence among imazethapyr-exposed pesticide applicators enrolled in the Agricultural Health Study (AHS). The AHS is a prospective cohort of 57,311 licensed pesticide applicators in the U.S., enrolled from 1993-1997. Among the 49,398 licensed pesticide applicators eligible for analysis, 20,646 applicators reported use of imazethapyr and 2,907 incident cancers developed through 2004. Imazethapyr exposure was classified by intensity-weighted lifetime exposure days calculated as [years of use 3 days per year 3 intensity level]. Poisson regression analysis was used to evaluate the relationship between imazethapyr exposure and cancer incidence. We found significant trends in risk with increasing lifetime exposure for bladder cancer (p for trend 0.01) and colon cancer (p for trend 0.02). Rate ratios (RRs) were increased by 137% for bladder cancer and 78% for colon cancer when the highest exposed were compared to the nonexposed. The excess risk for colon cancer was limited to proximal cancers, (RR 5 2.73, 95% confidence intervals 1.42, 5.25, p for trend 0.001). No association was observed for prostate, lung, rectum, kidney, oral, pancreas, lymphohematopoietic cancers or melanoma. These findings provide new evidence that exposure to aromatic amine pesticides may be an overlooked exposure in the etiology of bladder and colon cancer. The use of imazethapyr and other imidazolinone compounds should continue to be evaluated for potential risk to humans.

IMPORTANCE Tobacco products have changed in recent years. Contemporary mortality risk estimates of combustible tobacco product use are needed. OBJECTIVE To investigate the mortality risks associated with current and former use of cigars, pipes, and cigarettes. DESIGN, SETTING, AND PARTICIPANTS The National Longitudinal Mortality Study is a longitudinal population-based, nationally representative health survey with mortality follow-up that includes demographic and other information from the Current Population Survey, tobacco product use information from the Tobacco Use Supplement, and mortality data from the National Death Index. In this study, participants provided tobacco use information at baseline in surveys starting from 1985 and were followed for mortality through the end of 2011. The study includes 357 420 participants who reported exclusively using cigar, pipes, or cigarettes or reported never using any type of tobacco product. EXPOSURES Current or former exclusive use of any cigar (little cigar, cigarillos, large cigar), traditional pipe, or cigarette and never tobacco use. Information on current daily and nondaily use was also collected. Estimates adjusted for age, sex, race/ethnicity, education, and survey year. MAIN OUTCOMES AND MEASURES All-cause and cause-specific mortality as identified as the primary cause of death from death certificate information. RESULTS Of the 357 420 persons included in the analysis, the majority of current and former cigar and pipe smokers were male (79.3%-98.0%), and smokers were more evenly divided by sex (46% of current daily smokers were male). There were 51 150 recorded deaths during follow-up. Exclusive current cigarette smokers (hazard ratio [HR], 1.98; 95% CI, 1.93-2.02) and exclusive current cigar smokers (HR, 1.20; 95% CI, 1.03-1.38) had higher all-cause mortality risks than never tobacco users. Exclusive current cigarette smokers (HR, 4.06; 95% CI, 3.84-4.29), exclusive current cigar smokers (HR, 1.61; 95% CI, 1.11-2.32), and exclusive current pipe smokers (HR, 1.58; 95% CI, 1.05-2.38) had an elevated risk of dying from a tobacco-related cancer (including bladder, esophagus, larynx, lung, oral cavity, and pancreas). Among current nondaily cigarette users, statistically significant associations were observed with deaths from lung cancer (

IMPORTANCE An increasing proportion of US smokers smoke at low intensity and not every day. Some nondaily smokers have always had this pattern, whereas others previously smoked daily. The effect of reducing the level of smoking from daily to nondaily smoking and the dose response at low smoking levels are poorly understood. OBJECTIVE To evaluate risk of all-cause and cause-specific mortality among nondaily and daily cigarette smokers, by cigarettes per month, years after reducing from daily to nondaily smoking, and years since quitting. DESIGN, SETTING, AND PARTICIPANTS A prospective cohort study using harmonized data from multiple cycles of the Tobacco Use Supplements to the Current Population Survey (TUS-CPS), linked