Abstract
BackgroundAssociations between polycyclic aromatic hydrocarbons (PAHs) and colorectal cancer have been reported previously but few studies have characterized PAH exposure using biological measurements. We evaluated colorectal cancer risk in relation to urinary concentration of 1-hydroxypyrene glucuronide (1-OHPG), a polycyclic aromatic hydrocarbon (PAH) metabolite, and assessed determinants of PAH exposure among controls in the Shanghai Women’s Health Study (SWHS).MethodsConcentrations of 1-OHPG were measured in spot urine samples collected from 343 colorectal cancer cases and 343 individually matched controls. Questionnaires were administered to collect information on demographic characteristics and reported exposures. Odds ratios were calculated for risk of colorectal cancer in relation to quartiles of urinary 1-OHPG concentration. Potential determinants of natural log-transformed urinary 1-OHPG concentration were evaluated among a combined sample of controls from this study and another nested case–control study in the SWHS (Ntotal=652).ResultsNo statistically significant differences in risk of colorectal cancer by urinary 1-OHPG levels were observed. Among controls, the median (interquartile range) urinary 1-OHPG concentration was 2.01 pmol/mL (0.95-4.09). Active and passive smoking, using coal as a cooking fuel, eating foods that were cooked well done, and recent consumption of fried dough (e.g., yóutiáo) were associated with elevated levels of 1-OHPG, though only active smoking and fried dough consumption achieved statistical significance in multivariate analyses.ConclusionsThis study does not provide evidence of an association between urinary levels of 1-OHPG and risk of colorectal cancer among women. Several environmental and dietary sources of PAH exposure were identified. Overall, the levels of 1-OHPG in this population of predominantly non-smoking women were considerably higher than levels typically observed among non-smokers in Europe, North America, and other developed regions.
Highlights
Associations between polycyclic aromatic hydrocarbons (PAHs) and colorectal cancer have been reported previously but few studies have characterized PAH exposure using biological measurements
Few studies have evaluated the relationship between PAH exposure biomarkers and risk of colorectal adenoma [11] or colorectal cancer [12]. In this nested case–control study, we evaluated the risk of colorectal cancer in relation to urinary concentration of 1-hydroxypyrene glucuronide (1-OHPG), a metabolite of pyrene and an established biomarker of PAH exposure [13], among participants in the Shanghai Women’s Health Study
We evaluated urinary 1-OHPG concentration as a dependent variable in relation to selected exposures that were suspected a priori to contribute to PAH exposure
Summary
Associations between polycyclic aromatic hydrocarbons (PAHs) and colorectal cancer have been reported previously but few studies have characterized PAH exposure using biological measurements. Colorectal cancer mortality was elevated among PAH-exposed gas furnace workers in an occupational cohort study in Germany [4], and several case–control studies have reported associations between estimated dietary intake of benzo(a)pyrene, a particular PAH compound, and risk of colorectal adenoma [5,6,7,8]. In a prospective investigation within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, higher estimated dietary benzo(a)pyrene intake was associated with an increased risk of incident rectal adenoma but not colon adenoma [9]. Active cigarette smoking, a major source of PAH exposure, has been consistently associated with an increased risk of colorectal cancer [10]
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