Different profiles of carcinogen exposure in Chinese compared with US cigarette smokers

Abstract

Background Differences in carcinogen exposure from different cigarette products could contribute to differences in smoking-associated cancer incidence among Chinese compared with US smokers. Methods Urine concentrations of metabolites of nicotine, the tobacco-specific nitrosamine (TSNA) 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and polycyclic aromatic hydrocarbon metabolites (PAHs) were compared in 238 Chinese and 203 US daily smokers. Results Comparing Chinese versus US smokers, daily nicotine intake and nicotine intake per cigarette smoked were found to be similar. When normalised for cigarettes per day, urine NNAL excretion was fourfold higher in US smokers, while the excretion of urine metabolites of the PAHs fluorene, phenanthrene and pyrene metabolites was 50% to fourfold higher in Chinese smokers (all, p<0.0001). Similar results were seen when NNAL and PAHs excretion was normalised for daily nicotine intake. Conclusions Patterns of carcinogen exposure differ, with lower exposure to TSNA and higher exposure to PAHs in Chinese compared with US smokers. These results most likely reflect country differences in cigarette tobacco blends and manufacturing processes, as well as different environmental exposures.

Exposure to polycyclic aromatic hydrocarbons and volatile organic compounds among recently pregnant rural Guatemalan women cooking and heating with solid fuels

“…The urinary concentrations for 1-hydroxypyrene, a commonly used proxy for PAH exposure, were 0.083 ng/mg creatinine in NHANES (Alshaarawy et al, 2016), 2.5 ng/mg creatinine in Peru (Li et al, 2011), 7.68 ng/mg creatinine in Mexico (Pruneda-Alvarez et al, 2012), and 5.5 ng/mg creatinine in this study. Additionally, exposure to PAHs within this study are greater than that of heavy smokers (Benowitz et al, 2015) and, alarmingly, comparable to industrial exposure to coke ovens (Jongeneelen, 2001) even after excluding measurements taken after sauna use. VOC urinary metabolite concentrations in this study were greater than those seen in second-hand smokers (St Helen et al, 2014).…”

“…We compared our findings to published values that used the same lab methodology (Alwis et al, 2012; Benowitz et al, 2015; Campos et al, 2011; St Helen et al, 2014). The median individual mean urinary PAH metabolite concentrations among women exposed to wood smoke in this study were significantly higher than those of Chinese smokers (mean cigarettes per day = 18.0) across all PAHs (Benowitz et al, 2015) (Table 6). The median concentration of the most common urinary PAH metabolite measured, 1-hydroxypyrene, was 5.3 ng/mg creatinine (IQR: 2.9–9.1) among study participants and 0.8 ng/mg creatinine (IQR: 0.6–1.2) among smokers.…”

“… a Metabolite concentrations compared to values of Chinese smokers (mean cigarettes per day = 18.0) from Benowitz et al 2015 using the Wilcoxon signed-rank test. b Metabolite concentrations compared to values of American smokers (serum cotinine ≥ 10 ng/mL) from Alwis et al 2012 using the t test. c Metabolite concentrations compared to values of people exposed to cigarette smoke within a car for an hour from St. Helen st al.…”

“…In addition, elevated urinary concentrations of PAH and VOC metabolites have been found in the urine of cigarette smokers (Alwis et al, 2012; Benowitz et al, 2015), those exposed to secondhand smoke (St Helen et al, 2014; Suwan-ampai et al, 2009), and from occupational exposures, such as coal processing or aluminum production (Jongeneelen, 2001). Smoke from burning solid fuels typically contains high levels of PAHs (Titcombe and Simcik, 2011), VOCs (Vanker et al, 2015), and airborne fine particulate matter (PM 2.5 ) (Li et al, 2011; Titcombe and Simcik, 2011) and exposure to wood smoke from cooking is associated with high urinary levels of PAH metabolites (Pruneda-Alvarez et al, 2012).…”

Comparing the cancer potencies of emissions from vapourised nicotine products including e-cigarettes with those of tobacco smoke

“…VNP and cigarette emissions have been compared in this study using carcinogen concentrations, whereas normalisation to unit nicotine levels is sometimes preferred as an estimate of human exposure 49. Nicotine has an unprotonated (free-base) and two protonated forms, unprotonated nicotine being of greatest concern in terms of blood transfer.…”