Epidemiology of environmental tobacco smoke exposure

Implications of the Immune Landscape in COPD and Lung Cancer: Smoking Versus Other Causes

Cigarette smoking is reported in about one third of adults worldwide. A strong relationship between cigarette smoke exposure and chronic obstructive pulmonary disease (COPD) as well as lung cancer has been proven. However, about 15% of lung cancer cases, and between one fourth and one third of COPD cases, occur in never-smokers. The effects of cigarette smoke on the innate as well as the adaptive immune system have been widely investigated. It is assumed that certain immunologic features contribute to lung cancer and COPD development in the absence of smoking as the major risk factor. In this article, we review different immunological aspects of lung cancer and COPD with a special focus on non-smoking related risk factors.

Analyzing pesticides and metal(loid)s in imported tobacco to Saudi Arabia and risk assessment of inhalation exposure to certain metals

Exposure to toxic chemicals through smoked tobacco is a significant global public health issue due to their genotoxic and carcinogenic properties. The study aims to (1) measure Arsenic (As), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Mercury (Hg), Nickle (Ni), lead (Pb), and 407 pesticides in tobacco commercialized in Saudi Arabia; and (2) evaluate human health risks associated with smoking tobacco. Thus, we analyzed 60 tobacco samples per brand from eight of the most popular tobacco brands in the Saudi market. The analyzed tobacco contained significant concentrations of toxic metal (loid)s and banned pesticides. Twenty-three out of 407 pesticide residues were found, with an average concentration of 0.004-1.155 µg/g. Average concentrations of As, Cd, Co, Cr, Hg, Ni, and Pb for all brands were 0.16, 0.57, 0.75, 1.36, 1.94, 0.01, and 0.37 µg/g, respectively. The risk assessment indicated that high cancer risks are associated with exposure to As, Cd, Cr, and Ni, while lower risks are associated with Pb. Additionally, the potential cancer risk estimated for Cr was higher than other toxic elements. The cumulative cancer risks (95%) under three different cases for all brands were greater than the permissible limits (=10-4). The chances of getting cancer through inhalation of particulate As, Cd, Cr, Ni, and Pb was 4 in 10 000 cases in the best case scenario (1 cigarette per day). Therefore, metal content in cigarette tobacco should be reduced to improve public health.HIGHLIGHTSAll tested brands contained banned pesticide residues except for brand C.Tobacco samples contained significant concentrations of toxic metal(loid)s.A high risk of developing cancer is associated with exposure to As, Cd, Cr, and Ni, while a lower risk is associated with exposure to Pb.

Polyurethane-Based Face Mask as a Sampling Device for Environmental Tobacco Smoke

Environmental tobacco smoke (ETS), also known as secondhand smoking, contains human carcinogens associated with the development of many human diseases, including stroke, heart disease, leukemia, and lung cancer. Due to these adverse health effects, a sensitive and selective method is crucial for assessing the health impacts of ETS. While current methods to evaluate ETS exposure are either invasive or nonspecific and insensitive, in this study, we assessed the use of polyurethane foam face masks as a sampling medium to collect tobacco smoke-specific nicotine and nitrosamines for estimating personal exposure to ETS. This method was used in conjunction with tandem mass spectrometry coupled with isotope-dilution detection. After validation by comparison with the National Institute for Occupational Safety and Health standard method (NIOSH 2551) for nicotine, we quantitated ETS exposure in indoor and outdoor environments. The analysis shows the applicability of the method for monitoring nicotine down to ∼0.20 mg/m³ near an outdoor smoking hotspot and up to ∼5.2 mg/m³ in a room with burning cigarettes, all with a time resolution as short as 5 min. In comparison with the NIOSH method, the newly developed method is convenient, inexpensive, and does not require a personal sampling pump, thus can facilitate large-scale ETS exposure monitoring.

Passive smoking and type 2 diabetes among never-smoking women: The Japan Public Health Center-based Prospective Study

AIMS/INTRODUCTION

The aim of the current study was to prospectively evaluate the association between passive smoking from a spouse and the risk of diabetes among never-smoking Japanese women. Passive smoking at a workplace (or public facilities) was assessed as a secondary measure.

MATERIALS AND METHODS

In the Japan Public Health Center-based Prospective Study (baseline 1990 or 1993), we followed 25,391 never-smoking women aged 40-69 years and without diabetes. Passive smoking was defined as having a husband who was a self-reported smoker, and the exposure at a workplace (or public facilities) was self-reported by women. The development of diabetes was identified in questionnaires administered at the 5-year and 10-year surveys. A pooled logistic regression model was used to assess the association between passive smoking and the development of diabetes with adjustment for age and possible confounders.

RESULTS

Compared with women whose husbands had never smoked, women whose husband smoked ≥40 cigarettes/day had significantly higher odds of developing diabetes in an age-adjusted model, but the association was attenuated in a multivariable model (odds ratio 1.34, 95% confidence interval 0.96-1.87). There was a dose-response trend between the number of cigarettes smoked by a husband and the odds of developing diabetes (P = 0.02). Women reporting daily passive smoking at a workplace (or public facilities) had higher odds of developing diabetes than women reporting no such exposure (odds ratio 1.23, 95% confidence interval 0.995-1.53).

CONCLUSIONS

Our results indicated a higher risk of diabetes among never-smoking Japanese women with higher exposure to passive smoking from a spouse.

Independent and joint exposure to passive smoking and cooking oil fumes on oral cancer in Chinese women: a hospital-based case-control study

CONCLUSIONS

Passive smoking and COF exposure are independent risk factors for oral cancer in Chinese women, with the multiplicative interactions from combined exposures. Avoiding exposure to environmental tobacco smoke and COF may contribute to the prevention of oral cancer in Chinese women.

OBJECTIVE

To evaluate the independent and joint effects of passive smoking and cooking oil fumes (COF) on oral cancer in Chinese women.

METHODS

A case-control study was performed including 238 female patients with pathologically confirmed oral cancer and 470 controls as age-matched controls. Face-to-face interviews were conducted based on a structured questionnaire. The effects of passive smoking and COF exposure were analyzed using non-conditional logistic regression models.

RESULTS

Passive smoking significantly increased the risk of oral cancer in Chinese women: adjusted ORs were 2.12 (95% CI = 1.11-4.07) for those only exposed before age 18, 1.52 (95% CI = 1.01-2.31) for those only exposed after age 18, and 2.38 (95% CI = 1.47-3.85) for those both exposed before and after age 18. In addition, COF exposure was significantly associated with a risk of oral cancer (adjusted ORs were 1.69 (95% CI = 1.03-2.78) for light exposure and 2.06 (95% CI = 1.21-3.50) for heavy exposure). Furthermore, there was a significantly multiplicative interaction between passive smoking and COF for oral cancer.

Individual differences in cognitive ability at age 20 predict pulmonary function 35 years later

BACKGROUND

Poor pulmonary function is associated with mortality and age-related diseases, and can affect cognitive performance. However, extant longitudinal studies indicate that early cognitive ability also affects later pulmonary function. Despite the multifaceted nature of pulmonary function, most longitudinal studies were limited to a single index of pulmonary function: forced expiratory volume in 1 s (FEV1). In this study, we examined whether early adult cognitive ability predicted five different indices of pulmonary function in mid-life.

METHODS

Mixed modelling tested the association between young adult general cognitive ability (mean age=20), measured by the Armed Forces Qualification Test (AFQT), and mid-life pulmonary function (mean age=55), in 1019 men from the Vietnam Era Twin Study of Aging. Pulmonary function was indexed by per cent predicted values for forced vital capacity (FVC%p), FEV1%p, maximum forced expiratory flow (FEFmax%p), and maximal voluntary ventilation (MVV%p), and by the ratio of FEV1 to FVC (FEV1/FVC), an index of lung obstruction.

RESULTS

After adjusting for smoking, pulmonary disease, occupation, income and education, age 20 AFQT was significantly (p<0.05) associated with mid-life FVC%p (β=0.10), FEV1%p (β=0.13), FEFmax%p (β=0.13), and MVV%p (β=0.13), but was not significantly associated with FEV1/FVC (β=0.03, p=0.34).

CONCLUSIONS

Early adult cognitive ability is a predictor of multiple indices of aging-related pulmonary function 35 years later, including lung volume, airflow and ventilator capacity. Cognitive deficits associated with impaired aging-related lung function may, thus, be partly pre-existing. However, results also highlight that early life risk factors may be differentially related to different metrics of later-life pulmonary health.

Passive smoking and risk of type 2 diabetes: a meta-analysis of prospective cohort studies

Backgrounds/Objective

The prevalence of diabetes is increasing rapidly all over the world. However, studies on passive smoking and type 2 diabetes have not been systematically assessed. Therefore, we conducted a meta-analysis to explore whether an association exists between passive smoking and risk of type 2 diabetes.

Methods

We searched PubMed, EMBASE, Cochrane library and Web of Science up to April 9^th, 2013, to identify prospective cohort studies that assessed passive smoking and risk of type 2 diabetes. The fixed-effect model was used to calculate the overall relative risk (RR).

Result

4 prospective cohort studies were included for analysis, with a total of 112,351 participants involved. The pooled RR was 1.28 (95% confidence interval (CI) 1.14 to 1.44) comparing those who were exposed to passive smoking with those who were not. Subgroup, sensitivity analysis and publication bias test suggested the overall result of this analysis was robust.

Conclusions

Passive smoking is associated with a significantly increased risk of type 2 diabetes. Further well-designed studies are warranted to confirm this association.

Effects of second hand smoke on airway secretion and mucociliary clearance

The airway acts as the first defense against inhaled pathogens and particulate matter from the environment. One major way for the airway to clear inhaled foreign objects is through mucociliary clearance (MCC), an important component of the respiratory innate immune defense against lung disease. MCC is characterized by the upward movement of mucus by ciliary motion that requires a balance between the volume and composition of the mucus, adequate periciliary liquid (PCL) volume, and normal ciliary beat frequency (CBF). Airway surface fluid (ASL) is a thin layer liquid that consists of the highly viscous mucus upper “gel” layer, and the watery lubricating lower “sol” layer. Mucus production, secretion and clearance are considered to play a critical role in maintenance of airway health because it maintains hydration in the airway and traps particulates, bacteria, and viruses. Different types of epithelial cells, including secretory cells, and ciliated cells, contribute to the MCC function. Cigarette smoke (CS) contains chemicals and particulates that significantly affect airway secretion. Active and passive CS-induced chronic obstructive pulmonary disease (COPD) is frequently associated with hyperplasia of goblet cells and submucosal glands (SMGs), thus increasing the secretory capacity of the airways that impairs MCC.

Occupational gradients in smoking behavior and exposure to workplace environmental tobacco smoke: the multi-ethnic study of atherosclerosis

OBJECTIVE

This study examines associations of occupation with smoking status, amount smoked among current and former smokers (number of cigarettes per day and lifetime cigarette consumption (pack-years)), and workplace exposure to environmental tobacco smoke (ETS) independent from income and education.

METHODS

This is a cross-sectional analysis of data from a community sample (n = 6355, age range: 45-84) using logistic and multinomial regression. All analyses were stratified by sex and adjusted for socio-demographic variables.

RESULTS

Male blue-collar and sales/office workers had higher odds of having consumed more than 20 pack-years of cigarettes than managers/professionals. For both male and female current or former smokers, exposure to workplace ETS was consistently and strongly associated with heavy smoking and greater pack-years.

CONCLUSIONS

Blue-collar workplaces are associated with intense smoking and ETS exposure. Smoking must be addressed at both the individual and workplace levels especially in blue-collar workplaces.

Evaluation of Bronchiolar and Alveolar Cell Injuries Induced by Short- and Long-term Exposure to Sidestream Smoke

Background

We investigated effects of short- and long-term exposure to sidestream smoke on the bronchiolar and alveolar cells in Sprague-Dawley rats.

Methods

Rats were divided into five experimental groups: groups 1, 2, and 3 (1-month exposure to 3, 5, and 7 cigarettes a day, respectively), groups 4 and 5 (3- and 6 month exposure to five cigarettes a day, respectively). We examined the morphologic changes, the expressions of tumor necrosis factor α (TNF-α), tumor growth factor β1 (TGF-β1), interlekin (IL)-1α, IL-1β, Ki-67, and cytokeratin 14 and in situ apoptosis in the bronchiolar and alveolar cells on light microscopy (LM) and electron microscopic (EM) terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining.

Results

LM showed the respiratory bronchiolar dilatation and alveolar wall collapse. In groups 3, 4, and 5, EM showed loss of the cilia and Clara cells with irregular size, more prominent alveolar wall collapse and dilation of alveolar duct than those of groups 1 and 2. Bronchiolar and alveolar cells showed increased expressions of TNF-α and TGF-β in groups 4 and 5. LM and EM TUNEL stains showed increased apoptosis in groups 3, 4, and 5.

Conclusions

Sidestream smoke causes a bronchiolar and alveolar cell injury and the severity correlates strongly the volume and duration of exposure to sidestream smoke.

Methods in tobacco abuse: proteomic changes following second-hand smoke exposure

Smoking is one of the leading preventable causes of disease, disability, and death in the USA and leads to more than 400,000 preventable deaths per year. Nicotine is the major alkaloid present in tobacco smoke, and many of the negative effects of smoking are attributed to nicotine. Nicotine is not only the addictive component of tobacco smoke, but also highly associated with carcinogenesis and induces oxidative stress. Furthermore, the administration of nicotine via subcutaneous mini-osmotic pumps or by injection is an established method in preclinical studies for this area of research. Thus, preclinical research on the negative effects of tobacco smoke and tobacco addiction has focused primarily on the effects of nicotine. However, there are over 4,500 components found in tobacco smoke, many of which are highly toxic. Other components may also contribute to the addictive properties of tobacco smoke. Furthermore, the negative effects of tobacco smoke are not isolated to the smoker but can have negative effects to those exposed to the secondhand smoke (SHS) stream. SHS exposure is the third leading cause of preventable death. Approximately 38,000 deaths per year are attributed to SHS exposure in the USA. SHS exposure increases the risk of heart disease by approximately 30% and is associated with increased risk of stroke, cancer, type II diabetes, as well as pulmonary disease. Thus, methods of administering tobacco smoke in a controlled environment will further our understanding of tobacco addiction and the role tobacco smoke in other disease states. Moreover, combining smoke exposure with proteomics can lead to the discovery of biomarkers that can be potentially useful tools in screening, early diagnosis, prevention, and treatment of diseases caused by SHS.

Cigarette, cigar and pipe smoking, passive smoke exposure, and risk of pancreatic cancer: a population-based study in the San Francisco Bay Area

Background

To examine the influence of cigarette, cigar and pipe smoking, cessation of cigarette smoking and passive smoke exposure on the risk of pancreatic cancer.

Methods

Exposure data were collected during in-person interviews in a population-based case-control study of pancreatic cancer (N = 532 cases, N = 1701 controls) in the San Francisco Bay Area. Odds ratios (ORs) were adjusted for potential confounders.

Results

The adjusted odds ratio (OR) of pancreatic cancer among current smokers was 1.9 (95% confidence interval (CI), 1.4-2.7). A significant, positive trend in risk with increasing pack-years of smoking was observed (P-trend <0.0001). Compared with participants who continued to smoke, former smokers had no statistically significant elevation in risk of pancreatic cancer 10 years after smoking cessation, with risk reduced to that of never smokers regardless of prior smoking intensity. Both men and women experienced similar increased risk of pancreatic cancer with increasing smoking duration. Cigar and pipe smoking and exposure to passive smoke were not associated with pancreatic cancer.

Conclusions

Cigarette smoking is associated with an increased risk of pancreatic cancer. Smokers who had quit for ≥10 years no longer experienced an increased risk. Future work will help to determine the effect of declining smoking rates on pancreatic cancer incidence.

Assessment of "gene-environment" interaction in cases of familial and sporadic pancreatic cancer

INTRODUCTION

Pancreatic cancer (PC) is the fourth leading cause of cancer death in the United States. This study characterizes one of the largest national registries of familial PC (FPC) and sporadic PC (SPC), focusing on demographics, clinical factors, self-reported environmental and occupational lifetime exposures, and survival status.

BACKGROUND

Reported risk factors for PC include advancing age, a family history of PC, high-risk inherited syndromes, cigarette, cigar, and pipe smoking, exposure to occupational and environmental carcinogens, African-American race, high fat/high cholesterol diet, obesity, chronic pancreatitis, and diabetes mellitus.

PATIENTS AND METHODS

This retrospective cross-sectional, case-only analysis includes cases of FPC (n = 569) and SPC (n = 689) from the Johns Hopkins National Familial Pancreas Tumor Registry (NFPTR) enrolled between 1994 and 2005.

RESULTS

FPC smokers with environmental tobacco smoke (ETS) exposure were diagnosed at a significantly younger mean age (63.7 years) as compared to FPC non-smokers without ETS exposure (66.6 years; p = 0.05). Non-smoker ETS-exposed cases were diagnosed with PC at a significantly younger mean age (64.0 years) compared to non-smoker non-ETS-exposed cases (66.5 years) (p < 0.0004). The mean age at diagnosis for Ashkenazi Jewish SPC subjects was significantly younger (by 2.1 years) than Ashkenazi Jewish FPC cases (p = 0.05). In addition, Ashkenazi Jewish FPC subjects who smoked were diagnosed 5.9 years earlier than Ashkenazi Jewish FPC non-smokers (p = 0.05). The median length of survival for unresected FPC cases was significantly shorter (168 days) as compared to unresected SPC cases (200 days) (p = 0.04). Survival was improved in resected cases, 713 days for FPC cases and 727 days for SPC cases, but was not significantly different between the groups (p = 0.4). Mild to moderate multiplicative interaction was found between a family history of PC and exposure to asbestos, environmental radon, and environmental tobacco smoke (ETS), as evidenced by odds ratios >1.0.

CONCLUSIONS

These are the first data to show that occupational and environmental exposures may act synergistically with inherited or acquired genetic polymorphisms, resulting in earlier occurrence of PC. Exposure to cigarette smoking and ETS exposure in non-smokers when younger than 21 years of age are associated with a younger mean age of diagnosis in FPC and SPC cases and Ashkenazi Jewish smokers, when compared to non-exposed cases. Risk prediction models which take into account environmental exposures as well as family history may more accurately predict the risk of PC. High-risk individuals will likely benefit from early identification of pre-malignant lesions and molecular profiling, as methods of early detection, prevention, and personalized therapy.

Spousal smoking as an indicator of total secondhand smoke exposure

INTRODUCTION

This study assessed the utility of spousal smoking as a measure of secondhand smoke exposure. Methods The investigation involved secondary analysis of data from 526 female participants of a lung cancer case-control study from northeastern England. Secondhand smoke exposure was measured in the home (spousal and nonspousal), workplace, and social/other settings over the whole life course.

RESULTS

Almost all women (99.1%) had at least 10 years of secondhand smoke exposure from at least one source, most commonly from parental smoking in childhood, and spousal smoking, the workplace, and social settings during adulthood. Spousal smoking was strongly correlated with overall secondhand smoke exposure in the home over the life course but was weakly correlated (Kendall's tau = -.04 to .12) with secondhand smoke exposure from other domestic sources and with secondhand smoke exposure in the workplace or social/other settings. Most women who gave no history of spousal secondhand smoke exposure recalled at least 10 years of secondhand smoke exposure in other settings: in the home through other sources (83.2% > or = 10 "smoker-years"), through workplaces (63.4% > or =10 "exposure-years"), or in social settings (82.0% > or =10 exposure-years). Almost all (96.9%) reported at least 10 years of exposure from at least one of these nonspousal sources.

DISCUSSION

Using spousal smoking as a proxy of total secondhand smoke exposure would have meant that these subjects would have been misclassified as not exposed to secondhand smoke. This misclassification may bias estimates of association with health outcomes toward the null. Studies of the effects of secondhand smoke exposure on health outcomes should evaluate all potential sources of secondhand smoke exposure.

Second-hand smoke and human lung cancer

Since the early 1980s, there has been growing concern about potential health consequences of exposure to second-hand smoke (SHS). Despite SHS being established as a risk factor for lung cancer development, the estimated risk has remained small yet somehow debatable. Human exposure to SHS is complicated because of temporal variabilities in source, composition, and concentration of SHS. The temporality of exposure to SHS is important for human lung carcinogenesis with a latency of many years. To explore the causal effect of SHS in lung carcinogenesis, exposure assessments should estimate chronic exposure to SHS on an individual basis. However, conventional exposure assessment for SHS relies on one-off or short-term measurements of SHS indices. A more reliable approach would be to use biological markers that are specific for SHS exposure and pertinent to lung cancer. This approach requires an understanding of the underlying mechanisms through which SHS could contribute to lung carcinogenesis. This Review is a synopsis of research on SHS and lung cancer, with special focus on hypothetical modes of action of SHS for carcinogenesis, including genotoxic and epigenetic effects.

Interaction of the cytochrome P4501A2, SULT1A1 and NAT gene polymorphisms with smoking and dietary mutagen intake in modification of the risk of pancreatic cancer

Aromatic amines, N-nitroso compounds and heterocyclic amines are suspected human pancreatic carcinogens. Cytochrome P450 (CYP) 1A2, N-acetyltransferase (NAT) 1, NAT2 and sulfotransferase (SULT) are enzymes involved in the metabolism of these carcinogens. To test the hypothesis that genetic variations in carcinogen metabolism modify the risk of pancreatic cancer (PC), we investigated the effect of single-nucleotide polymorphisms (SNPs) of the CYP1A2, NAT1, NAT2 and SULT1A1 gene on modification of the risk of PC in a hospital-based study of 755 patients with pancreatic adenocarcinoma and 636 healthy frequency-matched controls. Smoking and dietary mutagen exposure information was collected by personal interviews. Genotypes were determined using the polymerase chain reaction–restriction fragment length polymorphism and Taqman methods. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional multivariate logistic regression analysis. We observed no significant main effects of any of these genes on the risk of PC. The CYP1A2 and NAT1 but not SULT1A1 and NAT2 genotypes showed significant interactions with heavy smoking in women not men. In contrast, a significant interaction between NAT1 genotype and dietary mutagen intake on modifying the risk of PC were observed among men but not women. The OR (95% CI) of PC was 2.23 (1.33–3.72) and 2.54 (1.51–4.25) for men having the NAT1*10 and a higher intake of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and benzo[a]pyrene, respectively, compared with individuals having no NAT1*10 or a lower intake of these dietary mutagens. These data suggest the existence of gender-specific susceptibility to tobacco carcinogen and dietary mutagen exposure in PC.

Predictors of support for environmental tobacco smoke bans in state government

BACKGROUND

Environmental tobacco smoke (ETS) is a major threat to public health, associated with a number of serious diseases, and a leading cause of death. Previous research demonstrates that enactment of government policies mandating clean indoor air is effective in creating more smoke-free public places and decreasing the incidence of smoking. Both researchers and community activists have an interest in understanding the factors that predict support for the regulation of ETS.

METHODS

This study examined predictors of support for regulating ETS by surveying 684 city and county public officials in Colorado who were interviewed by phone and mail (response rate 61%).

RESULTS

Thirty-five percent of public officials reported that it is a "serious" or "very serious" problem that nonsmokers breathe in other people's cigarette smoke, 21% were "neutral," and 42% said that it was "not serious" or "not serious at all." Results indicated that support for policies to control ETS and promote clean indoor air is significantly more prevalent among public officials who: (1) believe that tobacco use is a serious problem in their community, (2) believe that breathing environmental tobacco smoke is a serious problem for nonsmokers, (3) believe that city and county government should get involved with people's decisions about smoking, (4) support smoking-cessation programs for public employees, and (5) have smoked less than 100 cigarettes during their lifetime.

CONCLUSIONS

Both the harms of ETS and legislation to create smoke-free environments remain controversial among local officials. Smoke-free advocates should support officials who believe that ETS is a problem and persuade officials on the harms of ETS and the need for government intervention.

Active cigarette smoking, household passive smoke exposure, and the risk of developing pancreatic cancer

OBJECTIVE

The objective of this study was to examine the association between active cigarette smoking, household passive smoke exposure, and pancreatic cancer risk using a prospective cohort design.

METHODS

Two cohorts were established in Washington County, Maryland in 1963 (n = 45,749) and 1975 (n = 48,172). The Washington County Cancer Registry was used to ascertain the occurrence of pancreatic cancer in the 1963 cohort from 1963-1978 and in the 1975 cohort from 1975-1994. Poisson regression was used to analyze the associations between active smoking and household passive smoke exposure and pancreatic cancer risk.

RESULTS

Current active smoking was associated with a two-fold increased risk of pancreatic cancer in both cohorts. Among never-smokers in each cohort, exposure to household passive smoke was not associated with an increased risk of pancreatic cancer, although the confidence limits were wide due to a small number of cases.

CONCLUSIONS

This study further documents the approximate doubling of pancreatic cancer risk in current active smokers. Our results also indicate that household passive smoke exposure is not associated with pancreatic cancer risk, although our risk estimates lacked precision.

A summary of recent findings on birth outcomes and developmental effects of prenatal ETS, PAH, and pesticide exposures

Inner-city minority populations are high-risk groups for adverse birth outcomes and also more likely to be exposed to environmental contaminants, including environmental tobacco smoke (ETS), benzo[a]pyrene B[a]P, other ambient polycyclic aromatic hydrocarbons (global PAHs), and residential pesticides. The Columbia Center for Children's Environmental Health (CCCEH) is conducting a prospective cohort study of 700 northern Manhattan pregnant women and newborns to examine the effects of prenatal exposure to these common toxicants on fetal growth, early neurodevelopment, and respiratory health. This paper summarizes results of three published studies demonstrating the effects of prenatal ETS, PAH, and pesticides on birth outcomes and/or neurocognitive development [Perera FP, Rauh V, Whyatt RM, Tsai WY, Bernert JT, Tu YH, et al. Molecular evidence of an interaction between prenatal environment exposures on birth outcomes in a multiethnic population. Environ Health Perspect 2004;12:630-62; Rauh VA, Whyatt RM, Garfinkel R, Andrews H, Hoepner L, Reyes A, et al. Developmental effects of exposure to environmental tobacco smoke and material hardship among inner-city children. Neurotoxicol Teratol 2004;26:373-85; Whyatt RM, Rauh V, Barr DB, Camann DE, Andrews HF, Garfinkel R, et al. Prenatal insecticide exposures, birth weight and length among an urban minority cohort. Environ Health Perspect, in press]. To evaluate the effects of prenatal exposure to ETS, PAHs, and pesticides, researchers analyzed questionnaire data, cord blood plasma (including biomarkers of ETS and pesticide exposure), and B[a]P-DNA adducts (a molecular dosimeter of PAHs). Self-reported ETS was associated with decreased head circumference (P = 0.04), and there was a significant interaction between ETS and adducts such that combined exposure had a significant multiplicative effect on birth weight (P = 0.04) and head circumference (P = 0.01) after adjusting for confounders. A second analysis examined the neurotoxic effects of prenatal ETS exposure and postpartum material hardship (unmet basic needs in the areas of food, housing, and clothing) on 2-year cognitive development. Both exposures depressed cognitive development (P < 0.05), and there was a significant interaction such that children with exposure to both ETS and material hardship exhibited the greatest cognitive deficit (7.1 points). A third analysis found that cord chlorpyrifos, and a combined measure of cord chlorpyrifos, diazinon, and propoxur-metabolite, were inversely associated with birth weight and/or length (P < 0.05). These results underscore the importance of policies that reduce exposure to ETS, air pollution, and pesticides with potentially adverse effects on fetal growth and child neurodevelopment.

Smoking cessation and lung cancer mortality in a cohort of middle-aged Canadian women

PURPOSE

To determine the impact of smoking cessation on lung cancer mortality among women.

METHODS

Survival analysis is used to assess the effect of smoking cessation on lung cancer death in the dietary cohort of 49,165 women aged 40 to 59 years enrolled in the Canadian National Breast Screening Study.

RESULTS

During an average of 10.3 years of follow-up, 106 women died of lung cancer. The risk of lung cancer mortality among women who quit before age 50 (HR=0.26; 95% CI, 0.13-0.55 among women who quit at ages 40-49) or quit in the previous 10 years (HR=0.39; 95% CI, 0.22-0.69) is substantially lower than the risk among current smokers. Women who quit after age 40 or have quit for less than 20 years are at substantially higher risk of lung cancer mortality compared with never smokers. Both duration of smoking cessation and age at quitting have independent effects on lung cancer mortality, after controlling for number of cigarettes smoked per day and number of years smoked, as well as other potential confounding variables.

CONCLUSION

These findings suggest that programs and policies to promote early cessation of smoking and prevention of relapse should be a public health priority.

Multiplicity of abnormal promoter methylation in lung adenocarcinomas from smokers and never smokers

The prevalence of methylation of the p16, DAPK and RASSF1A genes was investigated in lung adenocarcinoma from smokers, former uranium miners and never smokers. The association between a common genetic alteration in adenocarcinoma, mutation of the K-ras gene and methylation of these genes, as well as survival was examined. Adenocarcinomas from 157 smokers, 46 never smokers and 34 former uranium miners were evaluated for methylation of the p16, DAPK and RASSF1A genes using the methylation-specific PCR assay. Comparisons were also made to prevalences of methylation of the MGMT gene and mutation of the K-ras gene previously examined in these tumors. The prevalence of methylation for all genes was similar between adenocarcinomas from smokers and never smokers, although the prevalence for methylation of the p16 gene tended to be higher in smokers compared to never smokers. A significantly higher prevalence for p16 methylation was seen in central vs. peripheral lung tumors. At least 1 gene was methylated in 35% of stage I tumors, whereas 2 and >/=3 genes were methylated in 40% and 16% of tumors, respectively. Methylation of all genes was independent of K-ras mutation, whereas methylation of the DAPK and RASSF1A genes was positively associated. Environmental tobacco smoke, the strongest lung cancer risk factor among never smokers, induces adenocarcinoma in part through inactivation of the p16, DAPK and RASSF1A genes. Adenocarcinomas may develop through 2 distinct processes: multiple gene inactivations through promoter hypermethylation and activation of the K-ras gene.

Respiratory health consequences of environmental tobacco smoke

Over the last several decades there has been a growing interest in examining the health consequences of environmental tobacco smoke (ETS). As a result of a wide body of research, ETS is now considered an unacceptable and entirely preventable public health hazard, and public policy increasingly discourages the presence of tobacco smoke in the public domain. This article provides an overview of the composition of ETS and the major diseases and disorders strongly linked to ETS, emphasizing the effects of ETS on pulmonary function, asthma, and lung cancer.

Developmental effects of exposure to environmental tobacco smoke and material hardship among inner-city children

Because of the growing concern that exposures to airborne pollutants have adverse effects on fetal growth and early childhood neurodevelopment, and the knowledge that such exposures are more prevalent in disadvantaged populations, we assessed the joint impact of prenatal exposure to environmental tobacco smoke (ETS) and material hardship on the 2-year cognitive development of inner-city children, adjusted for other sociodemographic risks and chemical exposures. The purpose was to evaluate the neurotoxicant effects of ETS among children experiencing different degrees of socioeconomic disadvantage, within a minority population. The sample did not include children exposed to active maternal smoking in the prenatal period. Results showed significant adverse effects of prenatal residential ETS exposure and the level of material hardship on 2-year cognitive development, as well as a significant interaction between material hardship and ETS, such that children with both ETS exposure and material hardship exhibited the greatest cognitive deficit. In addition, children with prenatal ETS exposure were twice as likely to be classified as significantly delayed, as compared with nonexposed children. Postnatal ETS exposure in the first 2 years of life did not contribute independently to the risk of developmental delay, over and above the risk posed by prenatal ETS exposure. The study concluded that prenatal exposure to ETS in the home has a negative impact on 2-year cognitive development, and this effect is exacerbated under conditions of material hardship in this urban minority sample.

Environmental tobacco smoke and the risk of pancreatic cancer: findings from a Canadian population-based case-control study

BACKGROUND

Despite the fact that tobacco is a well-recognized risk factor for pancreatic cancer, no study has yet reported on the association between environmental tobacco smoke (ETS) and this malignancy. We investigated the relationship between pancreatic cancer and childhood and adult exposure to ETS using a case-control study design.

METHODS

Our study population consisted of 583 pancreatic cancer cases and 4,813 population-based controls that were identified within 8 Canadian provinces between 1994 and 1997. Mail-out questionnaires were used to collect risk factor information and a lifetime residential and occupational history of exposure to ETS.

RESULTS

Among never smokers, those who were exposed to ETS both as a child and as an adult had an odds ratio of 1.21 (95% CI=0.60-2.44) relative to those with no exposure. For active smoking, when the referent group consisted of never smokers who had not been regularly exposed to ETS, the risk increases were more pronounced with an increased number of years of smoking, cigarette pack-years, years since quit smoking, and average number of cigarettes smoked daily.

CONCLUSIONS

Overall, our results are suggestive of a weak association between pancreatic cancer and ETS. Perhaps more importantly, they suggest that ETS smoking exposures may confound the risk of pancreatic cancer associated with active smoking measures commonly used in epidemiologic studies.

Influence of smoking on predictors of vascular disease

Beyond the already well-established strong causative relationship with cancer, smoking increases the risk for vascular disease. Smoking may act directly or adversely influence risk factors contributing to the development of vascular disease. Smoking causes endothelial dysfunction, dyslipidemia (decreased high-density lipoprotein cholesterol levels, hypertriglyceridemia and increased oxidation of low-density lipoprotein cholesterol) and platelet activation leading to a prothrombotic state. Smoking increases emerging risk factors (eg, fibrinogen, homocysteine, and high-sensitivity C-reactive protein) and increases insulin resistance and the risk of developing type 2 diabetes mellitus. The beneficial effects of statins and antioxidants (eg, vitamins C and E, beta-carotene) are counteracted by smoking. Smoking-induced alterations in growth factors, adhesion molecules, and even in genes can accelerate the progression of atherosclerosis. The aim of this review is to consider the adverse consequences of smoking on the factors predisposing to vascular disease and to emphasize the beneficial effects of smoking cessation.

Environmental tobacco smoke, carcinogenesis, and angiogenesis: a double whammy?

In this issue of Cancer Cell, Zhu and coworkers demonstrate that environmental tobacco smoke (ETS) results in tumor angiogenesis, and provide evidence that the responsible factor in ETS is nicotine. While a weak carcinogen, nicotine promotes carcinogenesis by a number of different mechanisms. The authors' findings provide further evidence of the harmful effects of ETS and indicate the desirability of reducing exposure to it.