Lung cancer and environmental tobacco smoke: occupational risk to nonsmokers

Meta-Analysis and Systematic Review in Environmental Tobacco Smoke Risk of Female Lung Cancer by Research Type

More than 50% of women worldwide are exposed to Environmental Tobacco Smoke (ETS). The impact of ETS on lung cancer remains unclear. Cohort studies since the late 1990s have provided new evidence of female lung cancer risk due to ETS. The objective of this meta-analysis and systematic review was to analyze the association of ETS with female lung cancer risk from 1997 to 2017, organised based on research design. According to our applied inclusion and exclusion criteria, 41 published studies were included. The relative risk (RR) from the cohort studies or odds ratio (OR) from case-control studies were extracted to calculate the pooled risks based on the type of study. The summary risks of ETS were further explored with the modulators of ETS exposure sources and doses. The pooled risks of lung cancer in non-smoking women exposed to ETS were 1.35 (95% CI: 1.17⁻1.56), 1.17 (95% CI: 0.94⁻1.44), and 1.33 (95% CI: 1.17⁻1.51) for case-control studies, cohort studies, and both types of studies, respectively. The summary RR estimate of the cohort studies was not statistically significant, but the RR increased with increasing doses of ETS exposure (p trend < 0.05). Based on the results of this study, ETS might be an important risk factor of female lung cancer in non-smokers.

Estimation of Annual Incidence of Lung Cancer Associated with Work Place Exposure to Passive Smoking in France

This study attempted to estimate the number of annual new cases of lung cancer from workplace exposure to Environmental Tobacco Smoke (ETS) in France. The number of new lung cancer cases attributable to workplace ETS exposure in France was estimated with regard to the following factors: excess risk of lung cancer from workplace ETS exposure, incidence of lung cancer in non-exposed non-smokers, and number of French workers exposed to passive smoking. The excess risk of lung cancer from workplace ETS exposure was estimated as from 0.12 to 0.39 by different references. The French workforce, regularly exposed to ETS in their workplace is about 3.2 millions. The incidence of lung cancer of non-smokers without exposure to ETS is between 3.7 to 10 per hundred thousand. If these three factors are combined, it is estimated that exposure to workplace passive smoking causes around 14 to 125 new cases of lung cancer each year in France. New lung cancer cases from workplace exposure to ETS represent a few percent of all occupational lung cancers, and a minuscule number in regards to the whole lung cancer annual incidence (14 to 125 for 23,000 lung cancers in France=0.06% to 0.54%).

Environmental tobacco smoke in the workplace: markers of exposure, polymorphic enzymes and implications for disease state

Studies focusing directly on tobacco smoke have tended to center on the differences in effect between smokers and non-smokers and many hundreds of such studies have been performed. In this review, we examine the current literature specifically concerning workplace exposure to environmental tobacco smoke (ETS) and its impact on individuals, particularly non-smokers and never smokers. The paper deals with quantifying and minimizing ETS exposures in a working environment, the effect of polymorphisms and other genetic factors that influence health outcomes after exposure to ETS and the association of occupational ETS exposure to disease-specific biomarkers.

Occupation and lung cancer in nonsmokers

Lung cancer remains a significant burden on society, with approximately 157,200 deaths from this disease in 2003 occurring in the United States alone. Smoking causes the vast majority of cases (and deaths) from lung cancer, occupation may account for as many as 16,700 of such deaths. To examine the influence of occupation independent of smoking, we reviewed the literature on occupational lung cancer in nonsmokers. We found that most individual studies and summaries of occupational lung cancer are based on data having a heavy preponderance of male smokers. Relatively little data are available concerning females and nonsmokers. Specific dose-response information is often lacking. Although many studies have been adjusted for smoking, there remains a significant potential for residual confounding because of the overwhelming importance of smoking in the etiology of this disease. Our review has found some evidence that asbestos, environmental tobacco smoke, and radon decay products (progeny) are occupational carcinogens in nonsmokers. Increased risk for lung cancer might also occur in nonsmokers from occupational exposure to arsenic. Nevertheless, for many agents and occupations occupations or industries listed in the database of the International Agency for Research on Cancer (IARC), we could not locate any study that found them to be occupational risk factors for lung cancer in nonsmokers. Thus, considerable uncertainty exists about their ability to cause lung cancer in the nonsmoking working population. We discuss problems with the original occupational studies and the IARC list of carcinogens. Besides the absence of information on nonsmokers, these problems include lack of sufficient detail on exposure to the primary agent of concern and to other occupational lung carcinogens. Further research on occupational causes of lung cancer in nonsmokers should be given high priority.

Epidemiology of lung cancer

In the United States, lung cancer remains the leading cause of cancer death in both men and women even though an extensive list of risk factors has been well-characterized. Far and away the most important cause of lung cancer is exposure to tobacco smoke through active or passive smoking. The reductions in smoking prevalence in men that occurred in the late 1960s through the 1980s will continue to drive the lung cancer mortality rates downward in men during the first portion of this century. This favorable trend will not persist unless further reductions in smoking prevalence are achieved.

Lung tumors in A/J mice exposed to environmental tobacco smoke: estimated potency and implied human risk

Directly inhaled tobacco smoke is a recognized human lung carcinogen, and epidemiological studies suggest relative risks of about 1.2-1.4 for nonsmoking spouses of smokers typically exposed to environmental tobacco smoke (ETS). While many individual ETS components have been shown experimentally to induce lung tumors, ETS itself was only recently shown to induce lung tumors in a series of studies in which strain A/J mice were exposed to well-defined ETS atmospheres. Data from these studies indicate that ETS exposure clearly can increase combined malignant and benign lung tumors in multiple experiments involving male and female A/J mice, and thus provide convincing evidence that ETS is a positive mouse carcinogen. Tumorigenic potencies estimated from these A/J mouse bioassay data predict a corresponding range of increased human risk (0.2-0.5%) that overlaps that implied by case-control studies showing increased lung cancer risks in lifelong nonsmokers married to smokers. In A/J mice exposed to a significantly tumorigenic ETS concentration, lung tumors were found to be significantly smaller than those in corresponding control mice, and mice so exposed for 9 months had significantly fewer tumors/animal than mice exposed for 5 months followed by 4 months in filtered ETS-free air. These findings support hypotheses that ETS does not promote growth of spontaneous neoplastic foci in A/J mice, and that ETS-induced lung-tumor risk in A/J mice occurs predominantly by genotoxic effects that can be suppressed by reduced cell proliferation associated with chronic, high-level ETS exposure. The results obtained add to evidence that A/J mouse lung tumors induced by ETS provide a relevant biological model of ETS-induced human lung tumors.

Mortality from occupational exposure to environmental tobacco smoke in Finland

This article aimed to estimate the mortality from exposure to passive smoking at work in Finland. The estimation used statistics on causes of death, exposure prevalences, and risk ratios from epidemiologic studies. The attributable fractions of cause-specific mortality from passive smoking at work were 2.8% for lung cancer, 1.1% for chronic obstructive pulmonary disease, 4.5% for asthma, 3.4% for ischemic heart disease, and 9.4% for cerebrovascular stroke. Altogether, about 250 fatalities were estimated to have occurred in 1996. This is approximately 0.9% of the total mortality in the Finnish population in the relevant disease and age categories. The magnitude of mortality related to past occupational exposure to passive smoking is considerable. Preventive measures to reduce environmental tobacco smoke in the workplace will be a powerful means of reducing the high burden of respiratory and cardiovascular diseases.

Summary: workshop on health risks attributable to ETS exposure in the workplace

This 1998 workshop was convened to address the health risks of exposure to environmental tobacco smoke (ETS) in the workplace. It was paired with a 1997 workshop on issues related to ETS exposure in work environments ((italic)1(/italic)). In the 1998 workshop, a multidisciplinary group of participants was charged with reviewing evidence on the quantitative risks to health posed by ETS and to discuss development of risk assessment methodology for the future. The overall charges for the present workshop were to consider various health outcomes and make recommendations regarding those health outcomes to be included in assessment of health risk resulting from ETS in the workplace; to consider available studies addressing these health outcomes and to evaluate the validity of data for estimating risk from occupational ETS exposure; to review and evaluate mathematical models useful for estimating the risk due to ETS exposure; to examine dose-response models and to characterize the models regarding validity and uncertainty in estimating health risk attributable to ETS exposure in the workplace.