Tobacco Smoke Is a Major Source of Aromatic Amine Exposure in U.S. Adults: 2013-2014 National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

Cigarette smoking increases the risk of cancer, cardiovascular diseases, and premature death. Aromatic amines (AA) are found in cigarette smoke and are well-established human bladder carcinogens.

METHODS

We measured and compared total urinary levels of 1-aminonaphthalene (1AMN), 2-aminonaphthalene (2AMN), and 4-aminobiphenyl (4ABP) in adults who smoked cigarettes exclusively and in adult nonusers of tobacco products from a nationally representative sample of non-institutionalized U.S. population in the 2013-2014 National Health and Nutrition Examination Survey.

RESULTS

Sample-weighted geometric mean concentrations of AAs in adults who smoked cigarettes exclusively compared with adult nonusers were 30 times higher for 1AMN and 4 to 6 times higher for 2AMN and 4ABP. We evaluated the association of tobacco-smoke exposure with urinary AAs using sample-weighted multiple linear regression models to control for age, sex, race/ethnicity, diet, and urinary creatinine. Secondhand smoke exposure status was categorized using serum cotinine (SCOT) among adult nonusers (SCOT ≤ 10 ng/mL). The exposure for adults who smoked cigarettes exclusively (SCOT > 10 ng/mL) was categorized on the basis of the average number of self-reported cigarettes smoked per day (CPD) in the five days prior to urine collection. The regression models show AAs concentration increased with increasing CPD (P < 0.001). Dietary-intake variables derived from the 24-hours recall questionnaire were not consistently significant predictors of urinary AAs.

CONCLUSIONS

This is the first characterized total urinary AA concentrations of the U.S. adult non-institutionalized population. Our analyses show that smoking status is a major contributor to AA exposures.

IMPACT

These data provide a crucial baseline for exposure to three AAs in U.S. non-institutionalized adults.

E-cigarette and Smokeless Tobacco Use and Switching Among Smokers: Findings From the National Adult Tobacco Survey

INTRODUCTION

Assessing the extent that cigarette smokers use or switch to e-cigarettes and smokeless tobacco can help inform the population health impact of these products. This study estimated the prevalence of e-cigarette and smokeless tobacco use and switching among current and recent former adult cigarette smokers.

METHODS

Data from the 2012-2013 (n=8,891) and 2013-2014 (n=11,379) National Adult Tobacco Survey were analyzed in 2016. Response rates for this telephone survey were 44.9% and 36.1%, respectively. Tobacco product use was assessed by smoking status.

RESULTS

Current e-cigarette use increased for all groups, with a greater increase among recent quitters, 9.1% (95% CI=7.1%, 11.1%) in 2012-2013 and 15.8% (95% CI=13.7%, 17.9%) in 2013-2014, than smokers with an unsuccessful quit attempt, 10.4% (95% CI=9.1%, 11.7%) in 2012-2013 and 14.8% (95% CI=13.5%, 16.1%) in 2013-2014, or smokers with no quit attempt, 5.9% (95% CI=4.8%, 6.9%) in 2012-2013 and 10.7% (95% CI=9.4%, 12.0%) in 2013-2014. Between 2012-2013 and 2013-2014, current use of smokeless tobacco remained steady for recent quitters (4.6% to 4.7%, p=0.92) and smokers with no quit attempt (4.0% to 4.3%, p=0.97), and decreased in smokers with an unsuccessful quit attempt (5.7% to 3.8%, p=0.004). More recent quitters completely switched to e-cigarettes in the past year (15.3% in 2012-2013, 25.7% in 2013-2014) than to smokeless tobacco (4.6% in 2012-2013, 4.5% in 2013-2014).

CONCLUSIONS

Current and recent former adult smokers are more likely to use e-cigarettes than smokeless tobacco. Current e-cigarette use was most prevalent among unsuccessful quitters and recent quitters, who were substantially more likely to report complete switching to e-cigarettes than smokeless tobacco.

Tobacco Product Use Among Adults - United States, 2015

Tobacco use remains the leading cause of preventable disease and death in the United States (1). Despite declining cigarette smoking prevalence among U.S. adults, shifts in the tobacco product landscape have occurred in recent years (2,3). Previous estimates of tobacco product use among U.S. adults were obtained from the National Adult Tobacco Survey, which ended after the 2013-2014 cycle. This year, CDC and the Food and Drug Administration (FDA) assessed the most recent national estimates of tobacco product use among adults aged ≥18 years using, for the first time, data from the 2015 National Health Interview Survey (NHIS), an annual, nationally representative, in-person survey of the noninstitutionalized U.S. civilian population. The 2015 NHIS adult core questionnaire included 33,672 adults aged ≥18 years, reflecting a 55.2% response rate. Data were weighted to adjust for differences in selection probability and nonresponse, and to provide nationally representative estimates. In 2015, 20.1 % of U.S. adults currently (every day or some days) used any tobacco product, 17.6% used any combustible tobacco product, and 3.9% used ≥2 tobacco products. By product, 15.1% of adults used cigarettes; 3.5% used electronic cigarettes (e-cigarettes); 3.4% used cigars, cigarillos, or filtered little cigars; 2.3% used smokeless tobacco; and 1.2% used regular pipes, water pipes, or hookahs.* Current use of any tobacco product was higher among males; persons aged <65 years; non-Hispanic American Indian/Alaska natives (AI/AN), whites, blacks, and persons of multiple races; persons living in the Midwest; persons with a General Educational Development (GED) certificate; persons with annual household income of <$35,000; persons who were single, never married, or not living with a partner or divorced, separated, or widowed; persons who were insured through Medicaid or uninsured; persons with a disability; and persons who identified as lesbian, gay, or bisexual (LGB). Current use of any tobacco product was 47.2% among adults with serious psychological distress compared with 19.2% among those without serious psychological distress. Proven population-level interventions that focus on the diversity of tobacco product use are important to reducing tobacco-related disease and death in the United States (1).

Flavoured non-cigarette tobacco product use among US adults: 2013-2014

INTRODUCTION

Limited data exist on flavoured non-cigarette tobacco product (NCTP) use among US adults.

METHODS

Data from the 2013 to 2014 National Adult Tobacco Survey (N=75 233), a landline and cellular telephone survey of US adults aged ≥18, were assessed to estimate past 30-day NCTP use, flavoured NCTP use and flavour types using bivariate analyses.

RESULTS

During 2013-2014, 14.4% of US adults were past 30-day NCTP users. Nationally, an estimated 10.2 million e-cigarette users (68.2%), 6.1 million hookah users (82.3%), 4.1 million cigar smokers (36.2%) and 4.0 million smokeless tobacco users (50.6%) used flavoured products in the past 30 days. The most prevalent flavours reported were menthol/mint (76.9%) for smokeless tobacco; fruit (74.0%) for hookah; fruit (52.4%), candy/chocolate/other sweet flavours (22.0%) and alcohol (14.5%) for cigars/cigarillos/filtered little cigars; fruit (44.9%), menthol/mint (43.9%) and candy/chocolate/other sweet flavours (25.7%) for e-cigarettes and fruit (56.6%), candy/chocolate/other sweet flavours (26.5%) and menthol/mint (24.8%) for pipes. Except for hookah and pipes, past 30-day flavoured product use was highest among 18-24-year olds. By cigarette smoking, never smoking e-cigarette users (84.8%) were more likely to report flavoured e-cigarette use, followed by recent former smokers (78.1%), long-term former smokers (70.4%) and current smokers (63.2%).

CONCLUSIONS

Flavoured NCTP use is prominent among US adult tobacco users, particularly among e-cigarette, hookah and cigar users. Flavoured product use, especially fruit and sweet-flavoured products, was higher among younger adults. It is important for tobacco prevention and control strategies to address all forms of tobacco use, including flavoured tobacco products.

Flavored Tobacco Product Use Among Middle and High School Students--United States, 2014

The 2009 Family Smoking Prevention and Tobacco Control Act prohibits "characterizing flavors" (e.g., candy, fruit, and chocolate) other than tobacco and menthol in cigarettes; however, characterizing flavors are not currently prohibited in other tobacco products. Analyses of retail sales data suggest that U.S. consumption of flavored noncigarette tobacco products, including flavored cigars and flavored e-cigarettes, has increased in recent years. There is growing concern that widely marketed varieties of new and existing flavored tobacco products might appeal to youths (2) and could be contributing to recent increases in the use of tobacco products, including e-cigarettes and hookah, among youths. CDC and the Food and Drug Administration (FDA) analyzed data from the 2014 National Youth Tobacco Survey (NYTS) to determine the prevalence of past 30 day use (current use) of flavored e-cigarette, hookah tobacco, cigar, pipe tobacco or smokeless tobacco products, and menthol cigarettes among middle and high school students, and the proportion of current tobacco product users who have used flavored products. An estimated 70.0% (3.26 million) of all current youth tobacco users had used at least one flavored tobacco product in the past 30 days. Among current users, 63.3%, (1.58 million) had used a flavored e-cigarette, 60.6%, (1.02 million) had used flavored hookah tobacco, and 63.5% (910,000) had used a flavored cigar in the past 30 days. Given the millions of current youth tobacco users, it is important for comprehensive tobacco prevention and control strategies to address all forms of tobacco use, including flavored tobacco products, among U.S. youths.

Systematic review of cigar smoking and all cause and smoking related mortality

Background

Cigars are a growing public health concern, given the changes in cigar use patterns in the US and elsewhere since the 1960s. We conducted a systematic review of published studies on current cigar smoking and all-cause and cause-specific mortality risks to inform potential regulatory approaches and future research that would strengthen the body of evidence.

Methods

Using 3 different databases and handsearching, we identified epidemiological studies published prior to June 2014 that examined the association between cigar smoking and all-cause mortality and smoking-related mortality. Detailed study characteristics as well as association-level characteristics, including effect estimates and 95% confidence intervals, were abstracted or calculated from each selected study.

Results

A total of 22 studies from 16 different prospective cohorts were identified. Primary cigar smoking (current, exclusive cigar smoking with no history of previous cigarette or pipe smoking) was associated with all cause-mortality, oral cancer, esophageal cancer, pancreatic cancer, laryngeal cancer, lung cancer, coronary heart disease (CHD), and aortic aneurysm. Strong dose trends by cigars per day and inhalation level for primary cigar smoking were observed for oral, esophageal, laryngeal, and lung cancers. Among primary cigar smokers reporting no inhalation, relative mortality risk was still highly elevated for oral, esophageal, and laryngeal cancers.

Conclusions

In summary, cigar smoking carries many of the same health risks as cigarette smoking. Mortality risks from cigar smoking vary by level of exposure as measured by cigars per day and inhalation level and can be as high as or exceed those of cigarette smoking. The body of evidence would be strengthened by future studies that focus on the health effects of primary cigar smoking and incorporate more contemporary and diverse study populations to better reflect the current patterns of cigar use in the US. Ideally, these studies would also collect detailed information on cigar type, exposure level, and biomarkers of exposure and potential harm.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1617-5) contains supplementary material, which is available to authorized users.

Tobacco use among middle and high school students - United States, 2011-2014

Tobacco use and addiction most often begin during youth and young adulthood. Youth use of tobacco in any form is unsafe. To determine the prevalence and trends of current (past 30-day) use of nine tobacco products (cigarettes, cigars, smokeless tobacco, e-cigarettes, hookahs, tobacco pipes, snus, dissolvable tobacco, and bidis) among U.S. middle (grades 6-8) and high school (grades 9-12) students, CDC and the Food and Drug Administration (FDA) analyzed data from the 2011-2014 National Youth Tobacco Surveys (NYTS). In 2014, e-cigarettes were the most commonly used tobacco product among middle (3.9%) and high (13.4%) school students. Between 2011 and 2014, statistically significant increases were observed among these students for current use of both e-cigarettes and hookahs (p<0.05), while decreases were observed for current use of more traditional products, such as cigarettes and cigars, resulting in no change in overall tobacco use. Consequently, 4.6 million middle and high school students continue to be exposed to harmful tobacco product constituents, including nicotine. Nicotine exposure during adolescence, a critical window for brain development, might have lasting adverse consequences for brain development, causes addiction, and might lead to sustained tobacco use. For this reason, comprehensive and sustained strategies are needed to prevent and reduce the use of all tobacco products among youths in the United States.

Modeling the potential effects of new tobacco products and policies: a dynamic population model for multiple product use and harm

BACKGROUND

Recent declines in US cigarette smoking prevalence have coincided with increases in use of other tobacco products. Multiple product tobacco models can help assess the population health impacts associated with use of a wide range of tobacco products.

METHODS AND FINDINGS

We present a multi-state, dynamical systems population structure model that can be used to assess the effects of tobacco product use behaviors on population health. The model incorporates transition behaviors, such as initiation, cessation, switching, and dual use, related to the use of multiple products. The model tracks product use prevalence and mortality attributable to tobacco use for the overall population and by sex and age group. The model can also be used to estimate differences in these outcomes between scenarios by varying input parameter values. We demonstrate model capabilities by projecting future cigarette smoking prevalence and smoking-attributable mortality and then simulating the effects of introduction of a hypothetical new lower-risk tobacco product under a variety of assumptions about product use. Sensitivity analyses were conducted to examine the range of population impacts that could occur due to differences in input values for product use and risk. We demonstrate that potential benefits from cigarette smokers switching to the lower-risk product can be offset over time through increased initiation of this product. Model results show that population health benefits are particularly sensitive to product risks and initiation, switching, and dual use behaviors.

CONCLUSION

Our model incorporates the variety of tobacco use behaviors and risks that occur with multiple products. As such, it can evaluate the population health impacts associated with the introduction of new tobacco products or policies that may result in product switching or dual use. Further model development will include refinement of data inputs for non-cigarette tobacco products and inclusion of health outcomes such as morbidity and disability.

A systematic review of transitions between cigarette and smokeless tobacco product use in the United States

Background

Smokeless tobacco use is becoming an increasingly important public health issue in the US and may influence cigarette smoking behavior. Systematic information on transitions between smokeless tobacco and cigarette use in the US is limited.

Methods

We conducted a systematic review of published literature on transitions between smokeless tobacco and cigarette use in the US. We searched PubMed, Web of Science and EbscoHost databases for all published articles from January 2000 to March 2014 that presented estimates of transitions in US youth and adult study populations over time between at least one of the following tobacco use states: exclusive cigarette smoking, exclusive smokeless tobacco use, dual use of both products, and use of neither product. We excluded non-English language studies, studies published before 2000, clinical trials, controlled cessation programs, and clinical studies or evaluations of smokeless tobacco cessation programs.

Results

The review identified six studies on US populations published since 2000 with longitudinal data on some or all of the transitions that users can undergo between smokeless tobacco and cigarette use. There was considerable heterogeneity across studies in design and tobacco use definitions. Despite these differences, the existing data indicate that switching behaviors from exclusive smoking to exclusive smokeless tobacco use are limited (adults: 0%-1.4%, adolescents: 0.8%-3.8%) but may be more common from exclusive smokeless tobacco use to exclusive smoking (adults: 0.9%-26.6%, adolescents: 16.6%-25.5%). Among adults, exclusive cigarette smoking was generally stable and consistent (79.7% to 87.6%) over follow-up across studies but less stable in adolescents (46.8%-78.7%). Exclusive smokeless tobacco use was less stable than exclusive cigarette smoking over time (adults: 59.4%-76.6%, adolescents: 26.2%-44.8%).

Conclusion

This review provides published estimates of the proportions of adults and adolescents transitioning between tobacco use categories from the most recently available studies on longitudinal transitions between smokeless tobacco and cigarettes in the US. These data can be used to track tobacco use behaviors and evaluate their effect on public health; however, the data for these studies were generally collected more than a decade ago. Additional research including nationally representative longitudinal estimates using consistent definitions and designs, would improve understanding of current tobacco transition behaviors.

Association between electronic cigarette use and openness to cigarette smoking among US young adults

INTRODUCTION

Use of electronic nicotine delivery systems (ENDS), including electronic cigarettes (e-cigarettes), is increasing. One concern is the appeal of these products to youth and young adults and the potential to influence perceptions and use of conventional cigarettes.

METHODS

Using data from the 2012-2013 National Adult Tobacco Survey, characteristics of adults aged 18-29 years who had never established cigarette smoking behavior were examined by ever use of e-cigarettes, demographics, and ever use of other tobacco products (smokeless tobacco, cigars, hookah, and cigarettes). Multivariate logistic regression was used to examine the relationship between e-cigarette use and openness to cigarette smoking among young adults, defined as the lack of a firm intention not to smoke soon or in the next year.

RESULTS

Among young adults who had never established cigarette smoking behavior (unweighted n = 4,310), 7.9% reported having ever tried e-cigarettes, and 14.6% of those who reported having ever tried e-cigarettes also reported current use of the product. Ever e-cigarette use was associated with being open to cigarette smoking (adjusted odds ratio = 2.4; 95% confidence interval = 1.7, 3.3), as was being male, aged 18-24 years, less educated, and having ever used hookah or experimented with conventional cigarettes.

CONCLUSIONS

Ever use of e-cigarettes and other tobacco products was associated with being open to cigarette smoking. This study does not allow us to assess the directionality of this association, so future longitudinal research is needed to illuminate tobacco use behaviors over time as well as provide additional insight on the relationship between ENDS use and conventional cigarette use among young adult populations.

Intentions to smoke cigarettes among never-smoking US middle and high school electronic cigarette users: National Youth Tobacco Survey, 2011-2013

INTRODUCTION

Electronic cigarette (e-cigarette) use is increasing rapidly, and the impact on youth is unknown. We assessed associations between e-cigarette use and smoking intentions among US youth who had never smoked conventional cigarettes.

METHODS

We analyzed data from the nationally representative 2011, 2012, and 2013 National Youth Tobacco Surveys of students in grades 6-12. Youth reporting they would definitely not smoke in the next year or if offered a cigarette by a friend were defined as not having an intention to smoke; all others were classified as having positive intention to smoke conventional cigarettes. Demographics, pro-tobacco advertisement exposure, ever use of e-cigarettes, and ever use of other combustibles (cigars, hookah, bidis, kreteks, and pipes) and noncombustibles (chewing tobacco, snuff, dip, snus, and dissolvables) were included in multivariate analyses that assessed associations with smoking intentions among never-cigarette-smoking youth.

RESULTS

Between 2011 and 2013, the number of never-smoking youth who used e-cigarettes increased 3-fold, from 79,000 to more than 263,000. Intention to smoke conventional cigarettes was 43.9% among ever e-cigarette users and 21.5% among never users. Ever e-cigarette users had higher adjusted odds for having smoking intentions than never users (adjusted odds ratio = 1.70, 95% confidence interval = 1.24-2.32). Those who ever used other combustibles, ever used noncombustibles, or reported pro-tobacco advertisement exposure also had increased odds for smoking intentions.

CONCLUSION

In 2013, more than a quarter million never-smoking youth used e-cigarettes. E-cigarette use is associated with increased intentions to smoke cigarettes, and enhanced prevention efforts for youth are important for all forms of tobacco, including e-cigarettes.

Little filtered cigar, cigarillo, and premium cigar smoking among adults--United States, 2012-2013

The burden of death and disease from tobacco use in the United States has been caused overwhelmingly by cigarettes and other smoked tobacco products. In the United States, cigarette consumption declined during 2000-2011; however, consumption of cigars more than doubled during the same period. The cigar market includes diverse product types manufactured with a variety of shapes and sizes, filters, tips, flavors, and prices. Although national estimates of cigar consumption have been reported previously, data characterizing who smokes different cigar types are limited. A recent analysis from the 2012-2013 National Adult Tobacco Survey (NATS) found that more than one in 20 U.S. adults smoke cigars "every day," "someday," or "rarely". This report expands upon those findings, using data from the 2012-2013 NATS to further characterize cigar smokers by the usual type of cigar smoked using the following categories: little filtered cigars (LFCs), cigarillos/other mass market cigars (cigarillos/MMCs), and premium cigars. The findings indicate that among U.S. adults who smoke cigars, 61.8% usually smoke cigarillos/MMCs, 19.9% usually smoke premium cigars, and the remainder, 18.4%, usually smoke LFCs. These data can help to inform public health interventions to reduce the burden of adverse health effects caused by cigar smoking in the United States, including regulation.

Cigar smoking among U.S. students: reported use after adding brands to survey items

BACKGROUND

Among U.S. youth overall, cigars are the most commonly used tobacco product after cigarettes. However, youth who identify their products by brand names, not general terms like "cigar," may underreport use.

PURPOSE

To examine changes in reported cigar (cigar, cigarillo, or little cigar) smoking among students following inclusion of cigar brand examples on the National Youth Tobacco Survey (NYTS).

METHODS

Data from the 2011 and 2012 NYTS and National Survey on Drug Use and Health (NSDUH) were analyzed in 2013 to estimate ever and current cigar smoking, overall and by race/ethnicity. The 2012 NYTS included cigar brand examples (Black and Mild, Swisher Sweets, Dutch Masters, White Owl, Phillies Blunt) in the survey instructions and ever use question, but the 2011 NYTS and 2011 and 2012 NSDUH did not.

RESULTS

NYTS ever cigar smoking was higher in 2012 (27.8%) than 2011 (19.5%) among black students overall. Current cigar smoking was 60%-70% higher among black females and students aged ≥ 17 years, in 2012 than 2011. For black females, current cigar smoking (11.5%) was two times greater than that of white females (4.3%) in 2012, whereas the prevalence among these subgroups was comparable in 2011. Similar changes were not observed among these subgroups in the 2011-2012 NSDUH.

CONCLUSIONS

This study highlights the high burden of cigar use among U.S. youth and suggests that NYTS ascertainment of cigar smoking may have improved by including brands. Disparities in cigar smoking need to be addressed to prevent and reduce all youth tobacco use.

Symptoms of tobacco dependence among middle and high school tobacco users: results from the 2012 National Youth Tobacco Survey

BACKGROUND

A growing body of evidence suggests that tobacco dependence symptoms can occur soon after smoking onset and with low levels of use. However, limited data are available nationally and among non-cigarette tobacco users.

PURPOSE

To examine the prevalence and determinants of tobacco dependence symptoms among adolescent tobacco users in the 2012 National Youth Tobacco Survey, a nationally representative, school-based survey of U.S. middle and high school students.

METHODS

Multivariate logistic regression was used to identify independent predictors of dependence symptoms among current users (i.e., past 30-day use) of cigarettes, cigars, or smokeless tobacco. Analyses were conducted in 2013 using SAS-callable SUDAAN, version 11 to account for the complex survey design.

RESULTS

Prevalence of tobacco dependence symptoms ranged from 20.8% (95% CI=18.6, 23.1) of current tobacco users reporting wanting to use tobacco within 30 minutes of waking to 41.9% (95% CI=39.3, 44.5) reporting recent strong cravings. Reporting of dependence symptoms was most consistently associated with polytobacco use, higher frequency of use, earlier initiation age, and female gender. A 2-4-fold increase in the odds of symptom reporting was found in adolescents using tobacco products on as few as 3-5 days compared to those who only used it for 1-2 of the past 30 days.

CONCLUSIONS

A substantial proportion of U.S. adolescent tobacco users, including those with low levels of use, report symptoms of tobacco dependence. These findings demonstrate the need for full implementation of evidence-based strategies to prevent both experimentation and progression to regular tobacco use among youth.

Menthol cigarettes, race/ethnicity, and biomarkers of tobacco use in U.S. adults: the 1999-2010 National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

In the United States, cigarette flavorings are banned, with the exception of menthol. The cooling effects of menthol could facilitate the absorption of tobacco toxicants. We examined levels of biomarkers of tobacco exposure among U.S. smokers of menthol and nonmenthol cigarettes.

METHODS

We studied 4,603 White, African-American, and Mexican-American current smokers 20 years of age or older who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2010 and had data on cigarette type and serum cotinine, blood cadmium, and blood lead concentrations. Urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) (NNAL) was studied in 1,607 participants with available measures.

RESULTS

A total of 3,210 (74.3%) participants smoked nonmenthol cigarettes compared with 1,393 (25.7%) participants who smoked menthol cigarettes. The geometric mean concentrations comparing smokers of nonmenthol with menthol cigarettes were 163.1 versus 175.9 ng/mL for serum cotinine; 0.95 versus 1.02 μg/L for blood cadmium; 1.87 versus 1.75 μg/dL for blood lead; and 0.27 versus 0.23 ng/mL for urine NNAL. After multivariable adjustment, the ratios [95% confidence interval (CI)] comparing smokers of menthol with nonmenthol cigarettes were 1.03 (0.95-1.11) for cotinine, 1.10 (1.04-1.16) for cadmium, 0.95 (0.90-1.01) for lead, and 0.81 (0.65-1.01) for NNAL.

CONCLUSIONS

In a representative sample of U.S. adult smokers, current menthol cigarette use was associated with increased concentration of blood cadmium, an established carcinogen and highly toxic metal, but not with other biomarkers.

IMPACT

These findings provide information regarding possible differences in exposure to toxic constituents among menthol cigarette smokers compared with nonmenthol cigarette smokers.

Smoking, menthol cigarettes, and peripheral artery disease in U.S. adults

INTRODUCTION

Cigarette flavorings, with the exception of menthol, have been banned in the United States under the Family Smoking Prevention and Tobacco Control Act. Given the large number of menthol cigarette smokers in the United States, we investigated whether cigarette type (nonmenthol or menthol) is associated with peripheral artery disease (PAD).

METHODS

The authors studied 5,973 adults, 40 years of age and older, who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004. Smoking status and cigarette type were derived from self-reported questionnaires. PAD was defined as an ankle-brachial blood pressure index <0.9 in at least 1 leg.

RESULTS

Fifty percent of participants were never-smokers compared to 31%, 14%, and 5% of former, current nonmenthol, and current menthol cigarette smokers, respectively. The weighted prevalence of PAD in the study population was 5%. After multivariable adjustment, the odds ratios for PAD were 1.44 (95% CI: 0.97, 2.15), 3.65 (95% CI: 1.57, 8.50), and 2.51 (95% CI: 1.09, 5.80) comparing former, current nonmenthol cigarette smokers, and current menthol cigarette smokers to never-smokers. The associations between smoking and PAD were similar for smokers of nonmenthol and menthol cigarettes (p value for heterogeneity = .59).

CONCLUSIONS

In a representative sample of the U.S. population, current use of both menthol and nonmenthol cigarettes was associated with increased prevalence of PAD, with no difference in risk between cigarette types.

Unplanned cigarette purchases and tobacco point of sale advertising: a potential barrier to smoking cessation

BACKGROUND

In the USA, tobacco marketing expenditure is increasingly concentrated at the point of sale (POS). Previous studies have demonstrated an association between exposure to tobacco POS advertising and increased smoking initiation, but limited evidence is available on adult smokers' decisions and behaviours.

METHODS

An immediate post-cigarette purchase survey was administered to 301 cigarette purchasers outside of two grocery stores in Vermont to assess the prevalence of unplanned purchases and opinions about POS tobacco advertising and displays.

RESULTS

In total, 11.3% of purchases were reported as unplanned. Certain groups were more likely to make unplanned purchases including: 18-24-year-olds (OR: 2.1, 95% CI 1.0 to 4.4), less than daily smokers (OR: 5.6, 95% CI 1.9 to 16.9), smokers who made 3+ quit attempts in the previous year (OR: 2.4, 95% CI 0.9 to 6.0), those who plan to quit in the next month (OR: 3.7, 95% CI 1.6 to 9.0), and those who agreed that tobacco POS advertising makes quitting smoking harder (OR: 2.3, 95% CI 1.1 to 4.8). Overall, 31.2% of participants agreed that tobacco POS advertising makes quitting smoking harder. Individuals who intended to quit within the next month, made 3+ quit attempts in the last year, or made an unplanned cigarette purchase were the most likely to agree.

CONCLUSIONS

Young adults and individuals making multiple quit attempts or planning to quit in the next month are more likely to make unplanned cigarette purchases. Reducing unplanned purchases prompted by tobacco POS advertising could improve the likelihood of successful cessation among smokers.

Environmental monitoring of secondhand smoke exposure

The complex composition of secondhand smoke (SHS) provides a range of constituents that can be measured in environmental samples (air, dust and on surfaces) and therefore used to assess non-smokers' exposure to tobacco smoke. Monitoring SHS exposure (SHSe) in indoor environments provides useful information on the extent and consequences of SHSe, implementing and evaluating tobacco control programmes and behavioural interventions, and estimating overall burden of disease caused by SHSe. The most widely used markers have been vapour-phase nicotine and respirable particulate matter (PM). Numerous other environmental analytes of SHS have been measured in the air including carbon monoxide, 3-ethenylpyridine, polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines, nitrogen oxides, aldehydes and volatile organic compounds, as well as nicotine in dust and on surfaces. The measurement of nicotine in the air has the advantage of reflecting the presence of tobacco smoke. While PM measurements are not as specific, they can be taken continuously, allowing for assessment of exposure and its variation over time. In general, when nicotine and PM are measured in the same setting using a common sampling period, an increase in nicotine concentration of 1 μg/m³ corresponds to an average increase of 10 μg/m³ of PM. This topic assessment presents a comprehensive summary of SHSe monitoring approaches using environmental markers and discusses the strengths and weaknesses of these methods and approaches.

Selenium and maternal blood pressure during childbirth

Evidence suggests selenium concentrations outside the nutritional range may worsen cardiovascular health. This paper examines the relationship between selenium and maternal blood pressure (BP) among 270 deliveries using umbilical cord serum as a proxy for maternal exposure levels. Multivariable models used linear splines for selenium and controlled for gestational age, maternal age, race, median household income, parity, smoking, and prepregnancy body mass index. Non-parametric analysis of this dataset was used to select spline knots for selenium at 70 and 90 μg/l. When selenium was <70 μg/l, increasing selenium levels were related to a non-statistically significant decrease in BP. For selenium 70-90 μg/l, a 1 μg/l increase was related to a 0.37 mm Hg (95% confidence interval (CI): 0.005, 0.73) change in systolic and a 0.35 mm Hg (0.07, 0.64) change in diastolic BP. There were very few selenium values >90 μg/l. Other studies indicate that the maternal/cord selenium ratio is 1.46 (95% CI: 1.28, 1.65). This u-shaped relationship between selenium and BP is consistent with a dual role of selenium as an essential micronutrient that is nonetheless a toxicant at higher concentrations; however, this needs to be studied further.

Low-level lead exposure and elevations in blood pressure during pregnancy

BACKGROUND

Lead exposure is associated with elevated blood pressure during pregnancy; however, the magnitude of this relationship at low exposure levels is unclear.

OBJECTIVES

Our goal was to determine the association between low-level lead exposure and blood pressure during late pregnancy.

METHODS

We collected admission and maximum (based on systolic) blood pressures during labor and delivery among 285 women in Baltimore, Maryland. We measured umbilical cord blood lead using inductively coupled plasma mass spectrometry. Multivariable models were adjusted for age, race, median household income, parity, smoking during pregnancy, prepregnancy body mass index, and anemia. These models were used to calculate benchmark dose values.

RESULTS

Geometric mean cord blood lead was 0.66 μg/dL (95% confidence interval, 0.61-0.70). Comparing blood pressure measurements between those in the highest and those in the lowest quartile of lead exposure, we observed a 6.87-mmHg (1.51-12.21 mmHg) increase in admission systolic blood pressure and a 4.40-mmHg (0.21-8.59 mmHg) increase in admission diastolic blood pressure after adjustment for confounders. Corresponding values for maximum blood pressure increase were 7.72 (1.83-13.60) and 8.33 (1.14-15.53) mmHg. Benchmark dose lower limit values for a 1-SD increase in blood pressure were < 2 μg/dL blood lead for all blood pressure end points.

CONCLUSIONS

A significant association between low-level lead exposures and elevations in maternal blood pressure during labor and delivery can be observed at umbilical blood lead levels < 2 μg/dL.

Body burdens of mercury, lead, selenium and copper among Baltimore newborns

Umbilical cord blood or serum concentrations of mercury, lead, selenium and copper were measured with inductively coupled plasma mass spectrometry in a population of 300 infants born in Baltimore, Maryland. Geometric mean values were 1.37 μg/L (95% confidence interval: 1.27, 1.48) for mercury; 0.66 μg/dL (95% CI: 0.61, 0.71) for lead; and 38.62 μg/dL (95% CI: 36.73, 40.61) for copper. Mean selenium was 70.10 μg/L (95% CI: 68.69, 70.52). Mercury, selenium and copper levels were within exposure ranges reported among similar populations, whereas the distribution of lead levels was lower than prior reports; only one infant had a cord blood lead above 10 μg/dL. Levels of selenium were significantly correlated with concentrations of lead (Spearman's ρ=0.20) and copper (Spearman's ρ=0.51). Multivariable analyses identified a number of factors associated with one of more of these exposures. These included: increase in maternal age (increased lead); Asian mothers (increased mercury and lead, decreased selenium and copper); higher umbilical cord serum n-3 fatty acids (increased mercury, selenium and copper), mothers using Medicaid (increased lead); increasing gestational age (increased copper); increasing birthweight (increased selenium); older neighborhood housing stock (increased lead and selenium); and maternal smoking (increased lead). This work provides additional information about contemporary prenatal element exposures and can help identify groups at risk of atypical exposures.

A systematic review of randomized controlled trials: Web-based interventions for smoking cessation among adolescents, college students, and adults

INTRODUCTION

Web-based treatments can deliver broad reaching, relatively inexpensive, and clinically tested methods for smoking cessation. We performed a systematic review of randomized controlled trials (RCTs) of smoking cessation to evaluate the efficacy of Web-based interventions in adults, college students, and adolescents.

METHODS

MEDLINE, EMBASE, The Cochrane Library, CINAHL, and PsycINFO were searched from January 1, 1990 through February 12, 2010 for RCTs examining the efficacy of Web-based smoking cessation programs. Paired reviewers abstracted data on study design, patient characteristics, and outcomes sequentially and did quality assessments independently.

RESULTS

Twenty-one RCTs met eligibility criteria, with 15 conducted among adults. Among adults, 2 RCTs found that a multicomponent intervention with Web and non-Web-based elements was more efficacious than a self-help manual, and one of 2 RCTs found that Web-based interventions may be more effective than no treatment. Three trials provided insufficient evidence to demonstrate whether Web-based interventions were more efficacious than counseling. By contrast, tailored Web sites in 2 RCTs and greater Web site exposure in 6 of 7 RCTs were associated with higher rates of abstinence. Among college students, evidence supporting use of Web-based interventions was insufficient because the one RCT conducted was also a multicomponent intervention. Five RCTs among adolescents demonstrated mixed results, with insufficient evidence supporting their efficacy.

CONCLUSIONS

Evidence supporting the use of Web-based interventions for smoking cessation is insufficient to moderate in adults and insufficient in college students and adolescents. These RCTs have, however, elucidated clinical, methodological, and statistical practices that are likely to improve future trial design and treatment delivery.

Fetal exposure to chlordane and permethrin mixtures in relation to inflammatory cytokines and birth outcomes

We sought to characterize the relationships between cord serum concentrations of chlordane and permethrin pesticides, inflammatory cytokines, gestational age, and size at birth. Umbilical cord serum levels of trans-nonachlor, oxychlordane, cis- and trans-permethrin, piperonyl butoxide, and cytokines (TNF-α, IFN-γ, IL-1β, IL-2, IL-6, IL-8, IL-10, IL-12p70, GMCSF) were quantified in 300 newborns at the Johns Hopkins Hospital in Baltimore, MD (2004-2005). Principal component analyses were used to quantitate chlordane and permethrin mixtures and to identify independent cytokine components. Five cytokine components described 87% of the variance in cord serum cytokine levels; these (and predominant loadings) were as follows: (1) all 9 cytokines; (2) acute phase (IL-1β, IL-6); (3) anti-inflammatory (IL-10); (4) TNF-α; and (5) IL-1β. Of these, the TNF-α component was significantly associated with a 2-day decrease in gestational age. Chlordane was associated with lower levels of the pro-inflammatory IL-1β [β: -0.11 (-0.20, -0.02)]. Permethrin was negatively associated with the anti-inflammatory cytokine IL-10 [β: -0.14 (-0.22, -0.05)]. Neither pesticides nor cytokines were significantly associated with birthweight, length, or head circumference, and pesticides were not associated with gestational age. Our findings suggest that chlordane and permethrin concentrations in cord blood may be associated with levels of inflammatory cytokines in the fetus.

Workplace smoking restrictions in China: results from a six county survey

OBJECTIVE

To determine the coverage of smoking restriction policies in indoor workplaces in China and to assess the relationships between these restrictive policies and secondhand smoke (SHS) exposure and smoking behaviours.

METHODS

A cross-sectional household survey was conducted in six counties in Sichuan, Jiangxi and Henan provinces in 2004. Using a standardised questionnaire, information on demographic characteristics, knowledge, attitudes and behaviours related to smoking and SHS exposure was collected through face-to-face interviews by trained local investigators among 12 036 respondents. Of respondents, 2698 individuals worked mainly indoors and were included in data analysis.

RESULTS

Only 28.5% of respondents reported that indoor workplaces had a smoke-free policy. Even when respondents reported smoke-free policies, 41.1% smokers reported that they were non-compliant with policies and smoked at work. In addition, 32.0% of non-smokers reported being exposed to SHS at work despite smoke-free policies. Non-smokers who reported no smoking restriction policies were 3.7 times more likely to be exposed to SHS than those working in smoke-free workplaces (adjusted OR 3.7, 95% CI 1.3 to 10.1). On average, respondents complying with smoke-free policies smoked 3.8 fewer cigarettes than those reporting no policies in their workplaces at a marginally non-significant level (p=0.06) (adjusted mean difference -3.8, 95% CI -8.0 to 0.5).

CONCLUSIONS

In China, few workplaces have implemented policies to restrict smoking, and, even in workplaces that have policies, workers report exposure to SHS while at their places of employment. Many workers report a lack of compliance with smoke-free policies. China needs better implementation of SHS policies to promote compliance. Working to improve implementation of smoke-free policies would promote cessation since Chinese smokers who were compliant with these efforts reported smoking fewer cigarettes per day.

Distribution and determinants of pesticide mixtures in cord serum using principal component analysis

We characterized the distribution and determinants of fetal exposures to pesticide mixtures using a cross-sectional study of 297 singletons delivered at Johns Hopkins Hospital in Baltimore, MD (2004-2005). Concentrations of nine persistent and twelve nonpersistent pesticides were measured in cord serum. Mixtures were identified using principal components analysis. Associations between mixtures and maternal and infant characteristics were evaluated using multivariate analysis. p,p'-DDE, p,p'-DDT, trans-nonachlor, oxychlordane, bendiocarb, propoxur, and trans- and cis-permethrin were detected in 100, 90, 93, 84, 73, 55, 52, and 41% of serum samples, respectively. There were four independent pesticide components: DDT (p,p'-DDT + p,p'-DDE), chlordane (trans-nonachlor + oxychlordane), permethrin (trans- and cis-permethrins + PBUT), and carbamate (bendiocarb + propoxur). DDT and chlordane were 6.1 (95%CI: 2.4, 15.5) and 2.1 (95%CI: 1.0, 4.2) times higher for infants of women >35, and 1.8 (95%CI: 1.2, 2.9) and 1.5 (95%CI: 1.1, 2.1) times higher in smoking mothers. DDT and carbamate were 15 (95%CI: 7, 30) and 2 (95%CI: 1, 4) times higher for infants of Asian compared with Caucasian mothers. No significant differences were observed for permethrin. Fetal exposures to pesticides are widespread, occur as mixtures, and differ by maternal race, age, and smoking status.

Estimating the risks and benefits of nicotine replacement therapy for smoking cessation in the United States

OBJECTIVES

To compare potential population-wide benefits and risks, we examined the potential impact of increased nicotine replacement therapy (NRT) use for smoking cessation on future US mortality.

METHODS

We developed a simulation model incorporating a Monte Carlo uncertainty analysis, with data from the 2005 National Health Interview Survey and Cancer Prevention Study II. We estimated the number of avoided premature deaths from smoking attributable to increased NRT use, before and after incorporating assumptions about NRT harm.

RESULTS

We estimate that a gradual increase in the proportion of NRT-aided quit attempts to 100% by 2025 would lead to 40,000 (95% credible interval=31,000, 50,000) premature deaths avoided over a 20-year period. Most avoided deaths would be attributable to lung cancer and cardiovascular disease. After we incorporated assumptions about potential risk from long-term NRT, the estimate of avoided premature deaths from all causes declined to 32 000.

CONCLUSIONS

Even after we assumed some harm from long-term NRT use, the benefits from increased cessation success far outweigh the risks. However, the projected reduction in premature mortality still reflects a small portion of the tobacco-related deaths expected over a 20-year period.

Global screening of human cord blood proteomes for biomarkers of toxic exposure and effect

BACKGROUND

Exposures of pregnant women to natural and manmade chemicals can lead to negative health effects in the baby, ranging from low birth weight to developmental defects. In some cases, diseases were postulated to have their basis in toxic exposure in utero or in early childhood. Therefore, an understanding of fetal responses to environmental exposures is essential. To that end, cord blood is a readily accessible biofluid whose proteomic makeup remains mostly unexplored when compared with that of adults.

OBJECTIVES

Our goal was an initial global assessment of the fetal serum proteome and for the identification of protein biomarkers indicative of toxic in utero exposures related to maternal cigarette smoking.

METHODS

Drawing from a repository of 300 samples, we selected umbilical cord blood sera from 12 babies born to six smokers and six nonsmokers and analyzed both sample pools by tandem mass spectrometry in conjunction with isobaric tags (iTRAQ) for protein quantification.

RESULTS

We identified 203 proteins, 17 of which were differentially expressed between the cigarette smoke-exposed and control populations. Most of the identified candidate biomarkers were biologically plausible, thereby underscoring the feasibility of screening neonates with global proteomic techniques for biomarkers of exposure and early biological effects triggered by in utero chemical exposures.

CONCLUSIONS

This validation study provides an initial view of the proteome of human cord blood sera; it demonstrates the feasibility of identifying therein by use of proteomics, biomarkers of environmental, toxic exposures.

Birth delivery mode modifies the associations between prenatal polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) and neonatal thyroid hormone levels

BACKGROUND

Developing infants may be especially sensitive to hormone disruption from chemicals including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs).

OBJECTIVE

We investigated relationships between cord serum levels of PCBs and PBDEs and thyroid hormones measured in cord blood serum and neonatal blood spots.

METHODS

We measured PCBs and PBDEs, thyrotropin (TSH), thyroxine (T4) and free T4 (FT4) in cord blood serum from 297 infants who were delivered at the Johns Hopkins Hospital in 2004-2005. We abstracted results of total T4 (TT4) measured in blood spots collected in the hospital and at neonatal visits. We used delivery mode (augmented vaginal deliveries and nonelective cesarean deliveries) as a surrogate for intrapartum stress, which is known to alter cord blood thyroid hormones.

RESULTS

In the full study population, no compounds were associated with a change in average TSH, FT4, or TT4. BDE-100 was associated with increased odds of low cord TT4, BDE-153 with increased odds of low cord TT4 and FT4, and no compounds were associated with increased odds of high TSH. For infants born by spontaneous, vaginal, unassisted deliveries, PCBs were associated with lower cord TT4 and FT4 and lower TT4 measured in neonatal blood spots. PBDEs showed consistent but mainly nonsignificant negative associations with TT4 and FT4 measurements.

CONCLUSIONS

Prenatal PCB and PBDE exposures were associated with reduced TT4 and FT4 levels among infants born by spontaneous, unassisted vaginal delivery. Intrapartum stress associated with delivery mode may mask hormonal effects of PCBs and PBDEs.

Maternal, infant, and delivery factors associated with neonatal thyroid hormone status

BACKGROUND

Thyroid function is dynamic during the perinatal period with many factors potentially influencing maternal, fetal and neonatal TSH and thyroid hormone levels. We sought to identify the impact of numerous maternal, fetal and delivery attributes on thyroid parameters in newborns.

METHODS

This was a cross sectional study of 300 newborns. Detailed information was obtained from medical records and multiple characteristics from the record were tested as predictors of cord blood serum total T4, free T4 and TSH and infant T4 levels from the Maryland newborn screening program.

MAIN OUTCOME

Outcomes are levels of thyroid stimulating hormone (TSH), thyroxine (T(4)), and free T(4) in newborn cord serum and total T(4) in postnatal heelstick bloodspot samples.

RESULTS

Multivariate models identified a number of variables that are independently associated with thyroid hormone levels: higher birth order (lower cord TSH); older maternal age (lower cord total T(4)); pregnancy-induced hypertension and/or preeclampsia (lower cord total T(4) and free T(4)); gestational diabetes (higher cord free T(4)); sexually transmitted disease during pregnancy (lower cord TSH); alcohol use during pregnancy (lower cord TSH); thyroid condition/medications (higher bloodspot total T(4), both neonatal and subsequent); Asian ancestry (higher cord TSH); male sex (higher TSH and lower neonatal bloodspot total T(4)); and C-section (lower cord TSH). Gestational age was independently associated with lower cord TSH, higher cord total T(4), and higher neonatal and subsequent bloodspot total T(4).

CONCLUSIONS

Fetal and newborn thyroid hormone levels during the perinatal period are dynamic and influenced by several biological and delivery related factors. Efforts to identify fetal thyroid disruptors in late gestation must carefully consider these factors.

Determinants of prenatal exposure to polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in an urban population

BACKGROUND

Recent studies have reported blood levels of polybrominated diphenyl ethers (PBDEs) in the U.S. population. Information about neonatal levels and about the relationship to polychlorinated biphenyls (PCBs) exposures is limited.

OBJECTIVES

The objective was to characterize levels and determinants of fetal exposure to PBDEs and PCBs among newborns from Baltimore, Maryland.

METHODS

We analyzed umbilical cord blood for eight PBDEs and 35 PCBs from infants delivered at the Johns Hopkins Hospital. Maternal and infant characteristics were abstracted from medical records.

RESULTS

Ninety-four percent of cord serum samples had quantifiable levels of at least one PBDE congener, and > 99% had at least one detectable PCB congener. PBDE concentrations in cord blood were similar to those reported in other studies from North America. Strong correlations were observed within but not across PCB and PBDE classes. Multivariate models showed that many factors independently predicted exposure to BDE-47, BDE-100, and BDE-153 and CB-118, CB-138/158, CB-153, and CB-180. Generally, infants of Asian mothers had lower PBDE and PCB levels, and infants of smokers had higher levels. Increased maternal body mass index was associated with lower levels of PCBs but not PBDEs. Levels of PCBs but not PBDEs were lower in births from married and multiparous mothers. Increased maternal age was associated with higher PCB levels but lower PBDE levels.

CONCLUSIONS

Although many of the factors we investigated were independent predictors of both PBDE and PCB levels, in some cases the direction of associations was different. More research is needed to better understand the sources and pathways of PBDE exposure.

Cord serum concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in relation to weight and size at birth

BACKGROUND

Recent studies have reported developmental toxicity among rodents dosed with perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA).

OBJECTIVES

We examined the relationship between concentrations of PFOS and PFOA in cord serum (surrogates for in utero exposures) and gestational age, birth weight, and birth size in humans.

METHODS

We conducted a hospital-based cross-sectional epidemiologic study of singleton deliveries in Baltimore, Maryland. Cord serum samples (n = 293) were analyzed for PFOS and PFOA by online solid-phase extraction, coupled with reversed-phase high-performance liquid chromatography-isotope dilution tandem mass spectrometry. Maternal characteristics and anthropometric measures were obtained from medical charts.

RESULTS

After adjusting for potential confounders, both PFOS and PFOA were negatively associated with birth weight [per ln-unit: beta = -69 g, 95% confidence interval (CI), -149 to 10 for PFOS; beta = -104 g, 95% CI, -213 to 5 for PFOA], ponderal index (per ln-unit: beta = -0.074 g/cm(3) x 100, 95% CI, -0.123 to -0.025 for PFOS; beta = -0.070 g/cm(3) x 100, 95% CI, -0.138 to -0.001 for PFOA), and head circumference (per ln-unit: beta = -0.32 cm, 95% CI, -0.56 to -0.07 for PFOS; beta = -0.41 cm, 95% CI, -0.76 to -0.07 for PFOA). No associations were observed between either PFOS or PFOA concentrations and newborn length or gestational age. All associations were independent of cord serum lipid concentrations.

CONCLUSIONS

Despite relatively low cord serum concentrations, we observed small negative associations between both PFOS and PFOA concentrations and birth weight and size. Future studies should attempt to replicate these findings in other populations.

Determinants of fetal exposure to polyfluoroalkyl compounds in Baltimore, Maryland

Polyfluoroalkyl compounds (PFCs), such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), are ubiquitous, man-made chemicals. Human data suggest that in utero exposures to these chemicals occur and some evidence of developmental toxicity in animals exists. To assess the distribution and determinants of fetal exposure to PFCs, we analyzed cord serum samples from 299 singleton newborns delivered between 2004 and 2005 in Baltimore, MD for 10 PFCs by employing on-line solid-phase extraction coupled with reversed-phase high-performance liquid chromatography-tandem mass spectrometry. PFOS and PFOA were detected in 99 and 100% of umbilical cord sera, with geometric mean concentrations of 4.9 and 1.6 ng/mL, respectively. PFOS and PFOA concentrations were highly correlated (Pearson's r = 0.64 after natural log transformation, p < 0.01). Eight other PFCs were detected less frequently and at lower concentrations than PFOS and PFOA. Geometric mean concentrations of PFOS for Asians (6.0 ng/mL) and Blacks (5.1 ng/mL) were higher than those for Whites (4.2 ng/mL), while PFOA levels were more evenly distributed by race. Other maternal demographic and socioeconomic characteristics, including age, education, marital status, and living in the city limits were not significantly associated with cord concentrations. Our findings suggest that in utero exposure to PFOS and PFOA is ubiquitous in a population of babies born in Baltimore, MD.

Socioeconomic and racial disparities in cancer risk from air toxics in Maryland

We linked risk estimates from the U.S. Environmental Protection Agency's National Air Toxics Assessment (NATA) to racial and socioeconomic characteristics of census tracts in Maryland (2000 Census) to evaluate disparities in estimated cancer risk from exposure to air toxics by emission source category. In Maryland, the average estimated cancer risk across census tracts was highest from on-road sources (50% of total risk from nonbackground sources), followed by nonroad (25%), area (23%), and major sources (< 1%). Census tracts in the highest quartile defined by the fraction of African-American residents were three times more likely to be high risk (> 90th percentile of risk) than those in the lowest quartile (95% confidence interval, 2.0-5.0). Conversely, risk decreased as the proportion of whites increased (p < 0.001). Census tracts in the lowest quartile of socioeconomic position, as measured by various indicators, were 10-100 times more likely to be high risk than those in the highest quartile. We observed substantial risk disparities for on-road, area, and nonroad sources by socioeconomic measure and on-road and area sources by race. There was considerably less evidence of risk disparities from major source emissions. We found a statistically significant interaction between race and income, suggesting a stronger relationship between race and risk at lower incomes. This research demonstrates the utility of NATA for assessing regional environmental justice, identifies an environmental justice concern in Maryland, and suggests that on-road sources may be appropriate targets for policies intended to reduce the disproportionate environmental health burden among economically disadvantaged and minority populations.

Livestock ammonia management and particulate-related health benefits

Agricultural operations are the largest source of ammonia emissions in the United States and contribute to the formation of ammonium nitrate and ammonium sulfate, two prevalent forms of fine particulate matter. Researchers have found an association between fine particulate matter and a variety of adverse healths effects, including premature mortality, chronic bronchitis, hospital admissions, and asthma attacks. Management practices that reduce ammonia emissions may decrease adverse health effects, resulting in significant economic benefits. We estimated the impact of a variety of emission controls, including diet optimization, alum, and incorporation of manure into the land. The results suggest that relatively modest management policies can have a significant impact on fine particulate formation in the atmosphere. Because of the heterogeneous nature of particulate matter, a key question is the importance of particulate matter size and composition. To the extent that ammonium nitrate and ammonium sulfate contribute to adverse health effects, ammonia management may have significant health implications. Our results suggestthat a 10% reduction in livestock ammonia emissions can lead to over $4 billion annually in particulate-related health benefits.

Systematic review: Exposure to pets and risk of asthma and asthma-like symptoms

BACKGROUND

Studies of exposure to pets and risk of asthma have yielded conflicting results.

OBJECTIVES

We performed a systematic review to synthesize the evidence of the effect of exposure to pets in the home on the risk of asthma and asthma-related symptoms. We also assessed differences between the studies as sources of heterogeneity of the results.

METHODS

We conducted a MEDLINE search (until the end of 1999) using the following boolean search command: (asthma[all] OR wheez*[all]) AND (domestic animal*[all] OR pets[all]). The outcome was limited to either diagnosis of asthma or the symptom of wheezing. The exposure of interest was domestic animals in the home. Appropriate temporal relationship was defined as present in studies with either pet keeping within the first 2 years of life, in the past, or exposure to pets preceding the outcome.

RESULTS

Thirty-two of the 217 retrieved articles fulfilled the eligibility criteria. Inappropriate time sequence of the exposure and outcome information was an important source of heterogeneity and an indication of potential selection bias. Therefore we analyzed studies focusing on early exposure or ensuring appropriate temporal sequence. The pooled risk estimates for both asthma (fixed-effects odds ratio, 1.11; 95% CI, 0.98-1.25; heterogeneity, P =.04; random-effects odds ratio, 1.09; 95% CI, 0.89-1.34) and wheezing (fixed-effects odds ratio, 1.19; 95% CI, 1.05-1.35; heterogeneity, P =.03; random-effects odds ratio, 1.17; 95% CI, 0.95-1.44) indicated a small effect, which was limited to studies with a median study population age of over 6 years (fixed-effects odds ratio, 1.19; 95% CI, 1.02-1.40; heterogeneity, P =.04; random-effects odds ratio, 1.15; 95% CI, 0.86-1.56; fixed-effects odds ratio, 1.29; 95% CI, 1.12-1.48; heterogeneity, P =.31). In younger children the harmful effect disappeared for wheezing (odds ratio, 0.80; 95% CI, 0.59-1.08; P =.38).

CONCLUSION

Exposure to pets appears to increase the risk of asthma and wheezing in older children. The observed lower risk among exposed than among unexposed young children is consistent with a protective effect in this age group but could also be explained by selection bias.