Faculty Bibliography

Although cigarette smoking continues to occur worldwide, there are few methods available to assess a person's retrospective exposure to mainstream smoke. The tobacco of cigarettes contains trace quantities of radioactive (210)Pb and (210)Po, which are volatilized and inhaled when a cigarette is smoked. It was hypothesized that urinary (210)Pb and (210)Po activity concentrations could be used as biomarkers of exposure to mainstream tobacco smoke. Human subjects (n = 250) were recruited from Beijing, China, and reported their smoking habits. Each subject provided a 24-hour urine sample, which was assayed for its (210)Pb and (210)Po activity concentrations. Although the urinary (210)Po activity from smoking was very low compared with background levels, the urinary (210)Pb activity correlated with the number of cigarettes smoked per day (CPD; rho = 0.38, P < 0.001) and the urinary cotinine concentration (rho = 0.52, P < 0.001). In a linear regression model, a 1-unit increase in CPD was associated with an increase of 0.13 mBq in urinary (210)Pb activity. In a logistic regression model, a 1-unit increase in urinary (210)Pb activity was associated with an estimated 25% increase in the odds of being a smoker. These data were modeled using the respiratory, gastrointestinal, and biokinetic models of the International Commission on Radiological Protection. When the final model was applied for a long-term smoker (20 CPD) that suddenly quits, the predicted urinary activity decreased to 50% of the steady-state activity in about 90 days. Based on this half-time estimate and the regression results, urinary (210)Pb can be used to assess the probability of having smoked in the past months. Cancer Epidemiol Biomarkers Prev; 19(2); 338-50

The radon decay products lead-210 ((210)Pb) and polonium-210 ((210)Po) are known components of tobacco. China is the world's largest producer and consumer of cigarettes, yet no comprehensive published reports of the (210)Pb and (210)Po activity concentrations in Chinese cigarettes are available. Twelve brands of cigarettes that were commonly smoked within a group of 184 Chinese smokers were selected for (210)Pb and (210)Po activity analysis. For each brand, the tobacco from two cigarettes was isolated, dried, weighed, spiked with a (209)Po tracer for yield, and digested with concentrated HNO3, followed by HCl. The polonium in each digested solution was spontaneously deposited onto a nickel disc. The polonium activity was then counted using alpha spectroscopy. The mean (range) (210)Po activity for all brands was 23 (18-29) mBq cig(-1). The state of radioactive equilibrium between (210)Po and (210)Pb in each cigarette was verified in three brands of cigarettes. Cigarettes from two brands were smoked on a machine in order to estimate the fraction of (210)Pb and (210)Po inhaled. An average of 8% of the (210)Pb and 13% of the (210)Po in the tobacco of the cigarettes was transferred to the mainstream smoke. It is thus estimated that a person smoking 20 of these cigarettes per day in China would inhale a mean (range) of 37 (29-46) mBq d(-1) of (210)Pb and 60 (47-75) mBq d(-1) of (210)Po. Cigarette smoking in China may therefore be a large source of a person's daily intake of (210)Pb and (210)Po

A total of 195 subjects, including 141 exposed workers and 54 farmers, were recruited in China to evaluate the usefulness of chromium (Cr) in erythrocytes as a biomarker of exposure to CrVI. The levels of Cr in red blood cells (RBC) were remarkably elevated even in a group of workers routinely exposed to CrVI as low as 5-15 microg m(-3) and showed a significant exposure-response trend over the exposure range from 0.002 to 1152 microg m(-3) (p <0.0001). Multiple linear regression analyses indicated that age and cigarette smoke were not associated with Cr in RBC. However, female subjects had lower Cr in RBC compared with their male counterparts for about the same exposure levels (p <0.05). The genotypes of band III, which encodes for anion transport protein and may regulate CrO4(-2) across cell membranes, were also identified and included for analysis. The ratios of Cr in RBC to CrVI exposure were higher in subjects with a wild genotype than in those who had heterozygous or homozygous variant alleles. However, the difference was not statistically significant probably due to the limited number of participating subjects. In addition, 15 of the 141 workers were selected for multiple exposure monitoring and blood sample collections to evaluate the inter- and intraindividual variations of Cr in RBC. Compared with the personal exposure levels, Cr in RBC had small intraindividual variations with a reliability coefficient of 0.88. The study suggests that Cr in RBC may serve as a sensitive and reliable biomarker for long-term exposure to CrVI

To provide quantitative evidence of the impact on people of a neighboring metropolitan airport, La Guardia Airport (LGA) in New York City, (1) airborne particulate matter (PM) was measured to determine whether concentration differences could be detected between homes that are upwind and downwind of the airport; (2) 24-hr noise measurements were made in 12 homes near the airport; and (3) the impact of noise was assessed by a Community Wellness and Health Promotion Survey. Particulate matter concentrations were higher during active airport operating hours than during nonoperating hours, and the percent increase varied inversely with distance from the airport. Hourly differences between paired upwind and downwind sites were not remarkable. Residents living near the airport were exposed to noise levels as much as four times greater than those experienced by residents in a quiet, comparison home. Impulse noise events were detected from both aircraft and vehicular traffic. More than 55% of the people living within the flight path were bothered by aircraft noise, and 63% by highway noise; these were significantly higher percentages than for residents in the nonflight area. The change in PM concentrations with distance during operating compared with nonoperating hours; traffic-related impulse noise events; and the elevated annoyance with highway noise, as well as aircraft noise among residents in the flight path area, show airport-related motor vehicle traffic to be a major contributor to the negative impact of airports on people in the surrounding communities

The present study was conducted in a Chinese population to evaluate the usefulness and sensitivity of PAH-DNA adduct as a biomarker of PAH exposure, and to examine the potential effects of smoking and polymorphisms of responsive genes on DNA adduct formation induced by PAH exposure. The polymorphisms of genes examined include GSTM1, GSTT1, CYP1A1, microsomal epoxide hydrolase (mEH) and excision repair cross-complementary group 2 (ERCC2). A total of 194 subjects with a broad range of PAH exposures were recruited, including 116 occupationally exposed workers, 49 metropolitan residents and 29 suburban gardeners. A significant exposure-response relationship was observed between PAH exposure and DNA adducts in leukocytes across the entire group of subjects (p < 0.0001). The levels of PAH-DNA adducts in the subgroup with lowest occupational exposure to PAHs (< 0.1 microg BaP m(-3)) was significantly higher than that in metropolitan residents and suburban gardeners. However, no significant difference was detected between residents and gardeners, with mean BaP concentrations of 0.028 and 0.011 microg m(-3), respectively. The polymorphisms of genes examined failed to show significant effects on PAH-induced adduct formation except ERCC2 Lys751Gln genotypes. A significantly higher level of PAH-DNA adduct was found in subjects with wild-type ERCC2 than those who have either heterozygous or homozygous variant alleles (p < 0.01). Smoking, age and gender did not substantially contribute to PAH-induced DNA adduct formation in this study. The study suggests that PAH-DNA adducts may serve as a reliable biomarker of PAH exposure in occupational settings but may not be sensitive enough to be used in populations with environmental exposures to PAHs