The roles of smoking and cooking emissions in lung cancer risk among Chinese women in Hong Kong

The trends in lung cancer prevalence, incidence, and survival in Hong Kong over the past two decades (2002-2021): a population-based study

Background

Over the past decades, significant progress in lung cancer management has been made. However, the trends in prevalence and survival of lung cancer in the Chinese population over the last decade remain unexplored. This study utilised a territory-wide electronic medical database in Hong Kong to provide the most up-to-date and comprehensive analysis of the trends in prevalence, incidence, and survival over the past two decades.

Methods

Descriptive epidemiology study using a retrospective cohort of lung cancer patients from the Clinical Data Analysis and Reporting System (CDARS). 10-year limited-duration prevalence, incidence, and relative period survival were calculated between 2002 and 2021. Sub-groups of age, sex, and comorbidity were examined. The annual percent change (APC) and average annual percent change (AAPC) were estimated using joinpoint regression.

Findings

This study included 87,259 incident cases between 2002 and 2021. The 10-year limited duration prevalence (per 100,000 persons) of lung cancer increased from 153.4 to 228.7 (AAPC: 3.08%). Crude incidence (per 100,000 persons) increased from 55.0 to 70.3 (APC: 1.23%), while age-standardised incidence decreased from 42.9 to 33.2 (APC: -1.32%). The 1-year and 5-year relative period survivals showed an increasing trend but remained low. Disparity in trends was observed among different sex and age groups.

Interpretation

Lung cancer burden has been increasing partly due to population ageing. Although survival showed improvement over the years, it remained low, highlighting the potential need for interventions. Further study exploring the disparity in sex-specific trends is warranted.

Funding

The Innovation and Technology Commission, Hong Kong.

Health effects associated with exposure to secondhand smoke: a Burden of Proof study

Despite a gradual decline in smoking rates over time, exposure to secondhand smoke (SHS) continues to cause harm to nonsmokers, who are disproportionately children and women living in low- and middle-income countries. We comprehensively reviewed the literature published by July 2022 concerning the adverse impacts of SHS exposure on nine health outcomes. Following, we quantified each exposure-response association accounting for various sources of uncertainty and evaluated the strength of the evidence supporting our analyses using the Burden of Proof Risk Function methodology. We found all nine health outcomes to be associated with SHS exposure. We conservatively estimated that SHS increases the risk of ischemic heart disease, stroke, type 2 diabetes and lung cancer by at least around 8%, 5%, 1% and 1%, respectively, with the evidence supporting these harmful associations rated as weak (two stars). The evidence supporting the harmful associations between SHS and otitis media, asthma, lower respiratory infections, breast cancer and chronic obstructive pulmonary disease was weaker (one star). Despite the weak underlying evidence for these associations, our results reinforce the harmful effects of SHS on health and the need to prioritize advancing efforts to reduce active and passive smoking through a combination of public health policies and education initiatives.

Age-period-cohort analysis and projection of cancer mortality in Hong Kong, 1998-2030

OBJECTIVES

To explore the relationship between immigration groups and cancer mortality, this study aimed to explore age, period, birth cohort effects and effects across genders and immigration groups on mortality rates of lung, pancreatic, colon, liver, prostate and stomach cancers and their projections.

DESIGN, SETTING, AND PARTICIPANTS

Death registry data in Hong Kong between 1998 and 2021, which were stratified by age, sex and immigration status. Immigration status was classified into three groups: locals born in Hong Kong, long-stay immigrants and short-stay immigrants.

METHODS

Age-period-cohort (APC) analysis was used to examine age, period, and birth cohort effects for genders and immigration groups from 1998 to 2021. Bayesian APC models were applied to predict the mortality rates from 2022 to 2030.

RESULTS

Short-stay immigrants revealed pronounced fluctuations of mortality rates by age and of relative risks by cohort and period effects for six types of cancers than those of long-stay immigrants and locals. Immigrants for each type of cancer and gender will be at a higher mortality risk than locals. After 2021, decreasing trends (p<0.05) or plateau (p>0.05) of forecasting mortality rates of cancers occur for all immigration groups, except for increasing trends for short-stay male immigrants with colon cancer (p<0.05, Avg+0.30 deaths/100 000 per annum from 15.47 to 18.50 deaths/100 000) and long-stay male immigrants with pancreatic cancer (p<0.05, Avg+0.72 deaths/100 000 per annum from 16.30 to 23.49 deaths/100 000).

CONCLUSIONS

Findings underscore the effect of gender and immigration status in Hong Kong on mortality risks of cancers that immigrants for each type of cancer and gender will be at a higher mortality risk than locals.

Air pollution: A culprit of lung cancer

Air pollution is a global health problem, especially in the context of rapid economic development and the expansion of urbanization. Herein, we discuss the harmful effects of outdoor and indoor pollution on the lungs. Ambient particulate matters (PMs) from industrial and vehicle exhausts is associated with lung cancer. Workers exposed to asbestos, polycyclic aromatic hydrocarbons (PAHs), and toxic metals are also likely to develop lung cancer. Indoors, cooking fumes, second-hand smoke, and radioactive products from house decoration materials play roles in the development of lung cancer. Bacteria and viruses can also be detrimental to health and are important risk factors in lung inflammation and cancer. Specific effects of lung cancer caused by air pollution are discussed in detail, including inflammation, DNA damage, and epigenetic regulation. In addition, advanced materials for personal protection, as well as the current government policies to prevent air pollution, are summarized. This review provides a basis for future research on the relationship between lung cancer and air pollution.

In vivo respiratory toxicology of cooking oil fumes: Evidence, mechanisms and prevention

BACKGROUND

As cooking is an essential part of people's daily life, cooking oil fumes (COF) has been recognized as one of the major indoor air pollutant. Mounting epidemiological evidence has indicated that COF exposure is significantly associated with an increased risk of various health effects including lung cancer, but toxicological studies are very limited.

OBJECTIVES

We conduct a systematic study to provide toxicological evidence of COF exposure on the lungs, to examine the underlying toxicological mechanism, and to suggest intervention measures to mitigate this toxicity.

METHODS

A total 96 female rats were randomly divided into control groups, COF exposure groups (0.2, 2, 20 mg/kg) and vitamin E protection groups, receiving appropriate treatment for 30 days. First we measured airway hyperresponsiveness (AHR) followed by a lung histological analysis to investigate the toxicological effects of COF. We next analyzed the biomarkers of oxidative stress, inflammation, and apoptosis to examine the underlying toxicological mechanism, and finally we investigated the protective effects of vitamin E against the toxicity of COF.

RESULTS

AHR measurement indicated that the airway resistance increased with the COF dose and the lung histological assay showed narrowing of the airway lumen, which provided evidence of the toxicological effects of COF. The biomarkers of oxidative stress (ROS and MDA), pro-inflammation (TNF-α and IL-1β), and apoptosis (NF-κB and Caspase-3) were all significantly increased with COF dose. We observed that above toxicological effects and biomarker levels induced by COF were significantly ameliorated after administration of VE.

CONCLUSION

The toxicity of cooking oil fumes on the lungs is clear from the evidence and mechanism, and can be ameliorated by vitamin E. We suggested that oxidative stress may be primarily responsible for the observed cooking oil fumes-induced toxicity.

Epidemiology and Survival Outcomes of Lung Cancer: A Population-Based Study

Purpose

Lung cancer has been the top-ranking cause of cancer deaths in Taiwan for decades. Limited data were available in global cancer surveillance regarding lung cancer epidemiology in Taiwan, and previous reports are outdated.

Patients and Methods

This population-based cohort study extracted data of patients with lung cancer from the Taiwan National Health Insurance database and determined the lung cancer incidence and prevalence during 2002–2014. Histological subtypes were retrieved from the Taiwan Cancer Registry database; survival rates were gathered from the National Death Registry. Average annual percentage changes (APCs) of prevalence, incidence, and overall survival were estimated by joinpoint regression analysis.

Results

Age-standardized incidence of lung cancer increased from 45.04 per 100,000 person-years in 2002 to 49.86 per 100,000 person-years in 2014, with an average APC of 0.7 (95% CI = 0.3–1.1; 0.2 in males, 2.0 in females). Lung cancer was more prevalent in male patients, but this increase gradually slowed down. Socioeconomic analysis showed that lung cancer has higher prevalence in patients with higher income level and urban residency. Adenocarcinoma was the most abundant histological subtype in Taiwan (adenocarcinoma-to-squamous cell carcinoma ratio = 4.16 in 2014), with a 2.4-fold increase of incident cases during 2002–2014 (from 43.47% to 64.89% of all lung cancer cases). The 5-year survival rate of lung cancer patients in 2010 was 17.34% (12.60% in male, 25.40% in female), with an average APC of 9.3 (6.3 in male, 11.8 in female) during 2002–2010.

Conclusion

Average APCs of prevalence and incidence of lung cancer were 3.1 and 0.7, respectively, during 2002–2014 in Taiwan. The number of female patients and number of patients with adenocarcinoma have increased the most, with incident cases doubling in these years. Facing this fatal malignancy, it is imperative to improve risk stratification, encourage early surveillance, and develop effective therapeutics for lung cancer patients in Taiwan.

Daily cooking duration and its joint effects with genetic polymorphisms on lung cancer incidence: Results from a Chinese prospective cohort study

OBJECTIVES

In this study, we conducted a prospective cohort study to investigate the joint effects of daily cooking duration with single nucleotide polymorphisms (SNPs) on lung cancer incidence.

MATERIALS AND METHODS

A total of 33,868 individuals recruited in 2013 from Dongfeng-Tongji cohort study were included in our research, in which 5178 participants were genotyped. Daily cooking duration was accessed by questionnaire, and the incident lung cancer cases were confirmed. Fifteen lung cancer related SNPs were selected according to the previous reports. We used the multiple Cox regression models to evaluate the separate and joint effects of daily cooking duration and SNPs on lung cancer incidence.

RESULTS

Each 1-h increase in daily cooking duration was associated with a 17% elevated risk of lung cancer incidence [hazard ratio (HR) (95%CI) = 1.17(1.03, 1.33)]. Specifically, subjects with daily cooking duration >2 h/day had a 2.05-fold increased incident risk of lung cancer than those without cooking [HR(95%CI) = 2.05(1.20, 3.53)] (P_trend = 0.011). The rs2395185 and rs3817963, both located at 6p21.32, were significantly associated with lung cancer incidence. Compared with no cooking subjects with rs2395185GG or rs3817963TT genotype, subjects with daily cooking >2 h/day and carrying rs2395185GT + TT genotypes had a 2.48-fold increased risk of lung cancer [HR(95%CI) = 2.48(1.03, 5.97)], and there were significant joint effects of rs3817963TC + CC with daily cooking 1-2 and >2 h/day [HR(95%CI) = 2.23(1.07, 4.64) and 2.22(1.05, 4.68), respectively].

CONCLUSIONS

Longer daily cooking duration, especially daily cooking >2 h/day, was associated with increased risk of lung cancer. There were significant joint effects of rs2395185 and rs3817963 with daily cooking duration on lung cancer incidence. This study offered a new indicator of cooking related pollution exposure and added new evidence for the joint effects of environment and genetic factors on lung cancer incidence.

A novel approach to evaluate the lung cancer risk of airborne particles emitted in a city

Air quality still represents a main threat to human health in cities. Even in developed countries, decades of air pollution control not yet allowed to reduce pollutant concentrations in urban areas adequately. Indeed, high airborne particle concentrations are measured in several European cities; this is a main issue since particles represent a carrier for carcinogenic compounds. Numerous researches measuring the exposure to the different aerosol metrics in urban areas were recently performed, nonetheless, few data on the lung cancer risk in such environments are available. In the present paper a novel approach to evaluate the lung cancer risk related to the airborne particles emitted by the different sources located in a city is proposed and applied to a pilot case-study (i.e. an Italian city). In particular, an existing lung cancer risk model was modified and applied to assess the particle-related lung cancer "emitted" by the different sources of the city using pollutant emission factors provided by accredited emission inventory databases. Therefore, the average toxicity of the particles emitted by the city (i.e. lung cancer slope factor) and the lung cancer risk globally emitted by the city, expressed as new cases of lung cancer, were evaluated. The proposed emission inventory also allowed to identify and localize the main contributors to the overall risk emitted in a city. As an example, for the city under investigation, the research revealed that the main contributor, amongst the sources considered, is the vehicular traffic which is characterized by a lower mass fraction of carcinogenic compounds but a much higher sub-micron particle emission with respect to the other sources.

Secular trends in incidence of lung cancer by histological type in Beijing, China, 20002016

Objective

The objective of this study was to characterize secular trends in the sex-specific, age-standardized incidence of lung cancer by histological type in Beijing, China, from 2000 to 2016 based on data from a population-based cancer registry.

Methods

Data on the incidence of cancer from 2000 to 2016 were obtained from the Beijing Cancer Registry. We examined trends in the sex-specific, age-standardized incidence of lung cancer by histological type using a Joinpoint regression model.

Results

A total of 117,409 cases of lung cancer were diagnosed from 2000 to 2016. Overall, 73,062 (62.23%) patients were males. The most common histological type among both sexes was adenocarcinoma; however, the proportion of adenocarcinoma differed significantly between males and females (45.36% vs. 77.14%, respectively, P<0.0001). The age-standardized incidence of total lung cancer increased from 2000 to 2010 with an annual percent change (APC) of 2.2% [95% confidence interval (95% CI), 1.5% to 2.9%] and stabilized thereafter. Among males, the incidence of total lung cancer peaked in 2008 and then decreased slightly, with an APC of −1.1% (95% CI, −2.1% to −0.1%). Among females, the incidence increased continuously during the study period, with an APC of 1.4% (95% CI, 0.9% to 1.9%). The incidence of squamous cell carcinoma decreased significantly in recent years among both sexes, with APCs of −2.6% (95% CI, −4.5% to −0.6%) from 2007 to 2016 for males and −5.4% (95% CI, −7.2% to −3.6%) from 2004 to 2016 for females. In contrast, the incidence of adenocarcinoma increased continuously throughout the study period, by APCs of 4.0% (95% CI, 2.6% to 5.4%) for males and 6.2% (95% CI, 4.8% to 7.6%) for females. The incidence of small cell carcinoma peaked in 2007 and stabilized thereafter among males, whereas it peaked in 2012 and then decreased with an APC of −14.7% (95% CI, −25.3% to −2.6%) among females. The incidence of large cell carcinoma and other specified malignant neoplasm did not change much, whereas the incidence of unspecified type decreased among both sexes during the study period.

Conclusions

Although the incidence of squamous cell carcinoma decreased significantly among both sexes in recent years in Beijing, China, adenocarcinoma increased continuously throughout the study period among both sexes. Knowledge of differences in trends is useful for surveillance and control of lung cancer. However, the reason for the increase in adenocarcinoma remains unclear and warrants investigation.

PI3K/Akt/HIF-1α signaling pathway mediates HPV-16 oncoprotein-induced expression of EMT-related transcription factors in non-small cell lung cancer cells

Background: Our previous studies have demonstrated that human papillomaviruse (HPV)-16 oncoproteins promoted epithelial-mesenchymal transition (EMT), leading to non-small cell lung cancer (NSCLC) progression, but the underlying molecular mechanisms still remain unclear. PI3K/Akt/HIF-1α signaling pathway has been reported to mediate hypoxia-induced EMT. In this study, we further explored the role of PI3K/Akt/HIF-1α signaling pathway in HPV-16 oncoprotein-induced EMT in NSCLC cells.

Methods: A549 and NCI-H460 NSCLC cells were transiently transfected with pEGFP-HPV-16 E6 or E7 constructs. Western blotting and RT-qPCR were respectively performed to determine the protein and mRNA expression of EMT-related transcription factors. HPV-16 E6 or E7-transfected NSCLC cells were co-transfected with specific HIF-1α-siRNA or pretreated with different concentrations of LY294002, a specific PI3K inhibitor, followed by the analysis of expression of EMT-related transcription factors. The correlation between HIF-1α and EMT-related transcription factors in NSCLC tissues was analyzed by immunohistochemical staining and Spearman rank correlation coefficient.

Results: HPV-16 E6 and E7 oncoproteins upregulated the expression of Slug and Twist1, the EMT-related transcription factors, at both protein and mRNA levels in A549 and NCI-H460 cells. The co-transfection with specific HIF-1α-siRNA, but not the non-specific (NS)-siRNA, significantly abrogated HPV-16 oncoprotein-induced upregulation of ZEB1, Snail1, Slug, and Twist1 at both protein and mRNA levels. Additionally, pretreatment with LY294002 obviously blocked HPV-16 E6- and E7-induced Snail1, Slug, and Twist1 protein expression in A549 and NCI-H460 cells. Further analysis of clinical specimens showed that HIF-1α protein was strongly expressed in NSCLC tissues, which was positively correlated with ZEB1, Snail1, Slug, and Twist1 protein expression.

Conclusions: PI3K/Akt/HIF-1α may contribute to the progression of HPV-associated NSCLC via mediating the expression of EMT-related transcription factors in NSCLC cells.

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.

The risk of lung cancer among cooking adults: a meta-analysis of 23 observational studies

PURPOSE

Cooking has been regarded as a potential risk factor for lung cancer. We aim to investigate the evidence of cooking oil fume and risk of lung cancer.

METHODS

Medline and Embase were searched for eligible studies. We conducted a meta-analysis to summarize the evidences of case-control or cohort studies, with subgroup analysis for the potential discrepancy. Sensitivity analysis was employed to test the robustness.

RESULTS

We included 23 observational studies, involving 9411 lung cancer cases. Our meta-analysis found that, for cooking female, the pooled OR of cooking oil fume exposure was 1.98 (95% CI 1.54, 2.54, I ² = 79%, n = 15) among non-smoking population and 2.00 (95% CI 1.46, 2.74, I ² = 75%, n = 10) among partly smoking population. For cooking males, the pooled OR of lung cancer was 1.15 (95% CI 0.71, 1.87; I ² = 80%, n = 4). When sub grouped by ventilation condition, the pooled OR for poor ventilation was 1.20 (95% CI 1.10, 1.31, I ² = 2%) compared to good ventilation. For different cooking methods, our results suggested that stir frying (OR = 1.89, 95% CI 1.23, 2.90; I ² = 66%) was associated with increased risk of lung cancer while not for deep frying (OR = 1.41, 95% CI 0.87, 2.29; I ² = 5%). Sensitivity analysis suggested our results were stable.

CONCLUSION

Cooking oil fume is likely to be a risk factor for lung cancer for female, regardless of smoking status. Poor ventilation may increase the risk of lung cancer. Cooking methods may have different effect on lung cancer that deep frying may be healthier than stir frying.

Best-worst scaling survey of preferences regarding the adverse effects of tobacco use in China

We use best–worst scaling to assess two types of concern levels of the adverse consequences of smoking in China. While the smoking cessation policy has worked well in Taiwan, more than 1 million people in mainland China are estimated to die every year from tobacco use. This study compares the preferences of Chinese individuals in the two jurisdictions (mainland versus Taiwan) and explores the possibility of information-based interventions. The relative importance of 13 adverse effects was assessed by conducting a web-based survey on a sample of 480 Chinese participants. The 13 items consist of various adverse effects of tobacco use: from long-term health risk, such as lung cancer and cardiovascular diseases, to reduction of physical capacity and sexual dysfunction, and disturbance to non-smokers. The resulting data suggest possible strategies to curb smoking. Subgroup analysis, focusing on gender, smoking status, and nicotine dependence, was also conducted. Lung cancer, cardiovascular diseases, and chronic obstructive pulmonary disease, in this order, rank highest for both types of respondents. On the other hand, high expenditures (13th) and weight gain after cessation (12th) are the lowest ranked for both. Measuring individual best–worst scores reveals substantial heterogeneity among respondents and that information-based intervention can help curb smoking.

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Best-worst scaling (BWS) is used to assess concerns on tobacco adverse effects.

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Adverse effects of tobacco are assessed for mainland and Taiwan residents.

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Lung cancer, cardiovascular diseases, and COPD rank highest for both.

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Information-based interventions are explored for Chinese smokers.

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Comparative results provide insights for a future anti-smoking policy.

Lung cancer-A global perspective

Lung cancer is the leading cause of cancer deaths worldwide. While tobacco exposure is responsible for the majority of lung cancers, the incidence of lung cancer in never smokers, especially Asian women, is increasing. There is a global variation in lung cancer biology with EGFR mutations being more common in Asian patients, while Kras mutation is more common in Caucasians. This review will focus on the global variations in lung cancer and its treatment.

The International Epidemiology of Lung Cancer: Latest Trends, Disparities, and Tumor Characteristics

INTRODUCTION

Our aim was to update global lung cancer epidemiology and describe changing trends and disparities.

METHODS

We presented country-specific incidence and mortality from GLOBOCAN 2012 by region and socioeconomic factors via the Human Development Index (HDI). Between- and within-country incidence by histological type was analyzed by using International Agency for Research on Cancer data on cancer incidence on five continents. Trend analyses including data from the International Agency for Research on Cancer, cancer registries, and the WHO mortality database were conducted using joinpoint regression. Survival was compared between and within countries and by histological type.

RESULTS

In 2012, there were 1.82 and 1.59 million new lung cancer cases and deaths worldwide, respectively. Incidence was highest in countries with a very high HDI and lowest in countries with a low HDI (42.2 versus 7.9 in 100,000 for males and 21.8 versus 3.1 in 100,000 for females, respectively). In most countries with a very high HDI, as incidence in males decreased gradually (ranging from -0.3% in Spain to -2.5% in the United States each year), incidence in females continued to increase (with the increase ranging from 1.4% each year in Australia to 6.1% in recent years in Spain). Although histological type varied between countries, adenocarcinoma was more common than squamous cell carcinoma, particularly among females (e.g., in Chinese females, the adenocarcinoma-to-squamous cell carcinoma ratio was 6.6). Five-year relative survival varied from 2% (Libya) to 30% (Japan), with substantial within-country differences.

CONCLUSIONS

Lung cancer will continue to be a major health problem well through the first half of this century. Preventive strategies, particularly tobacco control, tailored to populations at highest risk are key to reducing the global burden of lung cancer.

Polymorphisms in miR-135a-2, miR-219-2 and miR-211 as well as their interaction with cooking oil fume exposure on the risk of lung cancer in Chinese nonsmoking females: a case-control study

Background

The associations between microRNAs and lung cancer have received increasing attention. This study assess the association between polymorphisms in miR-135a-2, miR-219-2 and miR-211 genes and the risk of lung cancer, as well as the gene–environment interaction between these polymorphisms and cooking oil fume exposure.

Methods

A case–control study featuring 268 cases and 266 controls was conducted. The associations of miR-135a-2 rs10459194, miR-219-2 rs10988341 and miR-211 rs1514035 polymorphisms with the risk of lung cancer were analyzed. The gene–environment interactions were also reported on both additive and multiplicative scales.

Results

There were no statistically significant associations between the single-nucleotide polymorphisms (SNPs) and lung cancer or lung adenocarcinoma. The individuals with both a risk genotype of miRNA SNPs and exposure to a risk factor (cooking oil fumes) were at higher risk of lung cancer than those with only one of these two risk factors (odd ratios of 2.208, 1.285 and 1.813 for miR-135a-2 rs10459194; 2.164, 1.209 and 1.806 for miR-219-2 rs10988341; and 2.122, 1.146 and 1.725 for miR-211 rs1514035, respectively). However, the measures of biological interaction indicate that there was no such interaction between the three SNPs and exposure to cooking oil fumes on an additive scale. Logistic regression models also suggested that the gene–environment interactions were not statistically significant on a multiplicative scale.

Conclusions

There were no significant associations between the polymorphisms in miRNAs (miR-26a-1 rs7372209, miR-605 rs2043556 and miR-16-1 rs1022960) and the risk of lung cancer in the Chinese nonsmoking female population. The interactions between these polymorphisms in miRNAs and cooking oil fume exposure were also not statistically significant.

Environmental tobacco smoke exposure and lung cancer: A systematic review

AIM: To review evidence relating passive smoking to lung cancer risk in never smokers, considering various major sources of bias.

METHODS: Epidemiological prospective or case-control studies were identified which provide estimates of relative risk (RR) and 95%CI for never smokers for one or more of seven different indices of exposure to environmental tobacco smoke (ETS): The spouse; household; workplace; childhood; travel; social and other; and total. A wide range of study details were entered into a database, and the RRs for each study, including descriptions of the comparisons made, were entered into a linked database. RRs were derived where necessary. Results were entered, where available, for all lung cancer, and for squamous cell cancer and adenocarcinoma. “Most adjusted” results were entered based on results available, adjusted for the greatest number of potential confounding variables. “Least adjusted” results were also entered, with a preference for results adjusted at least for age for prospective studies. A pre-planned series of fixed-effects and random-effects meta-analyses were conducted. Overall analyses and analyses by continent were run for each exposure index, with results for spousal smoking given by sex, and results for childhood exposure given by source of ETS exposure. For spousal exposure, more extensive analyses provide results by various aspects of study design and definition of the RR. For smoking by the husband (or nearest equivalent), additional analyses were carried out both for overall risk, and for risk per 10 cigarettes per day smoked by the husband. These adjusted for uncontrolled confounding by four factors (fruit, vegetable and dietary fat consumption, and education), and corrected for misclassification of smoking status of the wife. For the confounding adjustment, estimates for never smoking women were derived from publications on the relationship of the four factors to both lung cancer risk and at home ETS exposure, and on the correlations between the factors. The bias due to misclassification was calculated on the basis that the proportion of ever smokers denying smoking is 10% in Asian studies and 2.5% elsewhere, and that those who deny smoking have the same risk as those who admit it. This approach, justified in previous work, balances higher true denial rates and lower risk in deniers compared to non-deniers.

RESULTS: One hundred and two studies were identified for inclusion, published in 1981 onwards, 45 in Asia, 31 in North America, 21 in Europe, and five elsewhere. Eighty-five were of case-control design and 17 were prospective. Significant (P < 0.05) associations were noted, with random-effects of (RR = 1.22, 95%CI: 1.14-1.31, n = 93) for smoking by the husband (RR = 1.14, 95%CI: 1.01-1.29, n = 45) for smoking by the wife (RR = 1.22, 95%CI: 1.15-1.30, n = 47) for workplace exposure (RR = 1.15, 95%CI: 1.02-1.29, n = 41) for childhood exposure, and (RR = 1.31, 95%CI: 1.19-1.45, n = 48) for total exposure. No significant association was seen for ETS exposure in travel (RR = 1.34, 95%CI: 0.94-1.93, n = 8) or in social situations (RR = 1.01, 95%CI: 0.82-1.24, n = 15). A significant negative association (RR = 0.78, 95%CI: 0.64-0.94, n = 8) was seen for ETS exposure in childhood, specifically from the parents. Significant associations were also seen for spousal smoking for both squamous cell carcinoma (RR = 1.44, 95%CI: 1.15-1.80, n = 24) and adenocarcinoma (RR = 1.33, 95%CI: 1.17-1.51, n = 30). Results generally showed marked heterogeneity between studies. For smoking by either the husband or wife, where 119 RR estimates gave an overall estimate of (RR = 1.21, 95%CI: 1.14-1.29), the heterogeneity was highly significant (P < 0.001), with evidence that the largest RRs were seen in studies published in 1981-89, in small studies (1-49 cases), and for estimates unadjusted by age. For smoking by the husband, the additional analyses showed that adjustment for the four factors reduced the overall (RR = 1.22, 95%CI: 1.14-1.31) based on 93 estimates to (RR = 1.14, 95%CI: 1.06-1.22), implying bias due to uncontrolled confounding of 7%. Further correction for misclassification reduced the estimate to a marginally non-significant (RR = 1.08, 95%CI: 0.999-1.16). In the fully adjusted and corrected analyses, there was evidence of an increase in Asia (RR = 1.18, 95%CI: 1.07-1.30, n = 44), but not in other regions (RR = 0.96, 95%CI: 0.86-1.07, n = 49). Studies published in the 1980’s, studies providing dose-response data, and studies only providing results unadjusted for age showed elevated RRs, but later published studies, studies not providing dose-response data, and studies adjusting for age did not. The pattern of results for RRs per 10 cigs/d was similar, with no significant association in the adjusted and corrected results (RR = 1.03, 95%CI: 0.994-1.07).

CONCLUSION: Most, if not all, of the ETS/lung cancer association can be explained by confounding adjustment and misclassification correction. Any causal relationship is not convincingly demonstrated.

Raw Garlic Consumption and Lung Cancer in a Chinese Population

BACKGROUND

Evidence of anticancer properties of garlic for different cancer sites has been reported previously in in vitro and in vivo experimental studies but there is limited epidemiologic evidence on the association between garlic and lung cancer.

METHODS

We examined the association between raw garlic consumption and lung cancer in a case-control study conducted between 2005 and 2007 in Taiyuan, China. Epidemiologic data was collected by face-to-face interviews from 399 incident lung cancer cases and 466 healthy controls. We used unconditional logistic regression models to estimate crude and adjusted ORs (aOR) and their 95% confidence intervals (CI). Adjusted models controlled for age, sex, average annual household income 10 years ago, smoking, and indoor air pollution.

RESULTS

Compared with no intake, raw garlic intake was associated with lower risk of development of lung cancer with a dose-response pattern (aOR for <2 times/week = 0.56; 95% CI, 0.39-0.81 and aOR for ≥2 times/week = 0.50; 95% CI, 0.34-0.74; Ptrend = 0.0002). Exploratory analysis showed an additive interaction of raw garlic consumption with indoor air pollution and with any supplement use in association with lung cancer.

CONCLUSIONS

The results of the current study suggest that raw garlic consumption is associated with reduced risk of lung cancer in a Chinese population.

IMPACT

This study contributes to the limited research in human population on the association between garlic and lung cancer and advocates further investigation into the use of garlic in chemoprevention of lung cancer. Cancer Epidemiol Biomarkers Prev; 25(4); 624-33. ©2016 AACR.

Health effects of carbon-containing particulate matter: focus on sources and recent research program results

Air pollution is a complex mixture of gas-, vapor-, and particulate-phase materials comprised of inorganic and organic species. Many of these components have been associated with adverse health effects in epidemiological and toxicological studies, including a broad spectrum of carbonaceous atmospheric components. This paper reviews recent literature on the health impacts of organic aerosols, with a focus on specific sources of organic material; it is not intended to be a comprehensive review of all the available literature. Specific emission sources reviewed include engine emissions, wood/biomass combustion emissions, biogenic emissions and secondary organic aerosol (SOA), resuspended road dust, tire and brake wear, and cooking emissions. In addition, recent findings from large toxicological and epidemiological research programs are reviewed in the context of organic PM, including SPHERES, NPACT, NERC, ACES, and TERESA. A review of the extant literature suggests that there are clear health impacts from emissions containing carbon-containing PM, but difficulty remains in apportioning responses to certain groupings of carbonaceous materials, such as organic and elemental carbon, condensed and gas phases, and primary and secondary material. More focused epidemiological and toxicological studies, including increased characterization of organic materials, would increase understanding of this issue.

The Global Burden of Cancer 2013

IMPORTANCE

Cancer is among the leading causes of death worldwide. Current estimates of cancer burden in individual countries and regions are necessary to inform local cancer control strategies.

OBJECTIVE

To estimate mortality, incidence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs) for 28 cancers in 188 countries by sex from 1990 to 2013.

EVIDENCE REVIEW

The general methodology of the Global Burden of Disease (GBD) 2013 study was used. Cancer registries were the source for cancer incidence data as well as mortality incidence (MI) ratios. Sources for cause of death data include vital registration system data, verbal autopsy studies, and other sources. The MI ratios were used to transform incidence data to mortality estimates and cause of death estimates to incidence estimates. Cancer prevalence was estimated using MI ratios as surrogates for survival data; YLDs were calculated by multiplying prevalence estimates with disability weights, which were derived from population-based surveys; YLLs were computed by multiplying the number of estimated cancer deaths at each age with a reference life expectancy; and DALYs were calculated as the sum of YLDs and YLLs.

FINDINGS

In 2013 there were 14.9 million incident cancer cases, 8.2 million deaths, and 196.3 million DALYs. Prostate cancer was the leading cause for cancer incidence (1.4 million) for men and breast cancer for women (1.8 million). Tracheal, bronchus, and lung (TBL) cancer was the leading cause for cancer death in men and women, with 1.6 million deaths. For men, TBL cancer was the leading cause of DALYs (24.9 million). For women, breast cancer was the leading cause of DALYs (13.1 million). Age-standardized incidence rates (ASIRs) per 100 000 and age-standardized death rates (ASDRs) per 100 000 for both sexes in 2013 were higher in developing vs developed countries for stomach cancer (ASIR, 17 vs 14; ASDR, 15 vs 11), liver cancer (ASIR, 15 vs 7; ASDR, 16 vs 7), esophageal cancer (ASIR, 9 vs 4; ASDR, 9 vs 4), cervical cancer (ASIR, 8 vs 5; ASDR, 4 vs 2), lip and oral cavity cancer (ASIR, 7 vs 6; ASDR, 2 vs 2), and nasopharyngeal cancer (ASIR, 1.5 vs 0.4; ASDR, 1.2 vs 0.3). Between 1990 and 2013, ASIRs for all cancers combined (except nonmelanoma skin cancer and Kaposi sarcoma) increased by more than 10% in 113 countries and decreased by more than 10% in 12 of 188 countries.

CONCLUSIONS AND RELEVANCE

Cancer poses a major threat to public health worldwide, and incidence rates have increased in most countries since 1990. The trend is a particular threat to developing nations with health systems that are ill-equipped to deal with complex and expensive cancer treatments. The annual update on the Global Burden of Cancer will provide all stakeholders with timely estimates to guide policy efforts in cancer prevention, screening, treatment, and palliation.

Interaction between Polymorphisms in Pre-MiRNA Genes and Cooking Oil Fume Exposure on the Risk of Lung Cancer in Chinese Non-Smoking Female Population

Background

Both genetic polymorphisms and environmental risk factors play important roles in the development of human chronic diseases including lung cancer. This is the first case-control study of interaction between polymorphisms in pre-miRNA genes and cooking oil fume exposure on the risk of lung cancer.

Methods

A hospital-based case-control study of 258 cases and 310 controls was conducted. Six polymorphisms in miRNAs were determined by Taqman allelic discrimination method. The gene-environment interactions were assessed on both additive and multiplicative scale. The statistical analyses were performed mostly with SPSS.

Results

The combination of the risk genotypes of five miRNA SNPs (miR-146a rs2910164, miR-196a2 rs11614913, miR-608 rs4919510, miR-27a rs895819 and miR-423 rs6505162) with risk factor (cooking oil fume exposure) contributed to a significantly higher risk of lung cancer, and the corresponding ORs (95% confidence intervals) were 1.91(1.04-3.52), 1.94 (1.16-3.25), 2.06 (1.22-3.49), 1.76 (1.03-2.98) and 2.13 (1.29-3.51). The individuals with both risk genotypes of miRNA SNPs and exposure to risk factor (cooking oil fumes) were in a higher risk of lung cancer than persons with only one of the two risk factors (ORs were 1.91, 1.05 and 1.41 for miR-146a rs2910164, ORs were 1.94, 1.23 and 1.34 for miR-196a2 rs11614913, ORs were 2.06, 1.41 and 1.68 for miR-608 rs4919510, ORs were 1.76, 0.82 and 1.07 for miR-27a rs895819, and ORs were 2.13, 1.15 and 1.02 for miR-423 rs6505162, respectively). All the measures of biological interaction indicate that there were not indeed biological interactions between the six SNPs of miRNAs and exposure to cooking oil fumes on an additive scale. Logistic models suggested that the gene-environment interactions were not statistically significant on a multiplicative scale.

Conclusions

The interactions between miRNA SNPs and cooking oil fume exposure suggested by ORs of different combination were not statistically significant.

Joint effects of environmental exposures and familial susceptibility to lung cancer in Chinese never smoking men and women

OBJECTIVES

Previous epidemiological studies had limited power to investigate the joint effects of individual environmental risk factors and familial susceptibility to lung cancer. This study aimed to address this shortcoming.

METHODS

We recruited 345 never smoking lung cancer cases and 828 community referents. We developed a collective environmental exposure index by assigning a value of 1 to subjects at high risks regarding environmental risk factors and 0 otherwise, and then summed over using weights equivalent to the excess odds ratio. Potential additive and multiplicative interactions between environmental exposure index and family cancer history were examined.

RESULTS

Compared with "low environmental exposure and without family cancer history", the odds ratio was 6.80 (95% confidence interval = 3.31-13.98) for males who had high environmental exposures but without family cancer history, whereas it increased to 30.61 (95% confidence interval = 9.38-99.87) if they also had a positive family history. The corresponding associations became weaker in never smoking females. No multiplicative interaction was observed for both genders and an additive interaction was restricted among males.

CONCLUSIONS

This study developed a novel environmental exposure index that offers sufficient interest deserving further studies on the interactions between environmental exposures and familial susceptibility to lung cancer risk.

Elevated levels of mercapturic acids of acrolein and crotonaldehyde in the urine of Chinese women in Singapore who regularly cook at home

Lung cancer is unusually common among non-smoking women in Southeastern Asia but the causes of this frequently fatal disease are not well understood. Several epidemiology studies indicate that inhalation of fumes from high temperature Chinese style cooking with a wok may be a cause. Only one previous study investigated uptake of potential toxicants and carcinogens by women who cook with a wok. We enrolled three-hundred twenty-eight non-smoking women from Singapore for this study. Each provided a spot urine sample and answered a questionnaire concerning their cooking habits and other factors. The urine samples were analyzed by liquid chromatography-tandem mass spectrometry for mercapturic acid metabolites of acrolein (3-hydroxypropylmercapturic acid), crotonaldehyde (3-hydroxy-1-methylpropylmercapturic acid), and benzene (S-phenylmercapturic acid), accepted biomarkers of uptake of these toxic and carcinogenic compounds. We observed statistically significant effects of wok cooking frequency on levels of 3-hydroxypropylmercapturic acid and 3-hydroxy-1-methylpropylmercapturic acid, but not S-phenylmercapturic acid. Women who cooked greater than 7 times per week had a geometric mean of 2600 (95% CI, 2189-3090) pmol/mg creatinine 3-hydroxypropylmercapturic acid compared to 1901 (95% CI, 1510-2395) pmol/mg creatinine when cooking less than once per week (P for trend 0.018). The corresponding values for 3-hydroxy-1-methylpropylmercapturic acid were 1167 (95% CI, 1022-1332) and 894 (95% CI, 749-1067) pmol/mg creatinine (P for trend 0.008). We conclude that frequent wok cooking leads to elevated exposure to the toxicants acrolein and crotonaldehyde, but not benzene. Kitchens should be properly ventilated to decrease exposure to potentially toxic and carcinogenic fumes produced during Chinese style wok cooking.

Smoking among Hong Kong Chinese women: behavior, attitudes and experience

BACKGROUND

The numbers of women smoking have risen 72.5% since 1990 with the increasing population - from 56,100 to 96,800 in 2012, reflecting an alarming situation in Hong Kong. The study aimed to describe the smoking behaviour, attitudes and associated factors among women in Hong Kong.

METHODS

A qualitative cross-sectional study involving semi-structured interview was conducted with Chinese women from five community centres in different districts in Hong Kong in 2010. A purposive sample of 73 female participants (24 current smokers, 20 ex-smokers and 29 never-smokers) were recruited. The 73 women were classified by their smoking status and age to form 15 focus groups.

RESULTS

Most informants knew about the general health hazards of smoking, such as cancer and heart or respiratory diseases, but not about the female-specific health consequences of smoking. A few smokers considered smoking to be a weight control strategy, fearing a gain in weight if they gave up. Moreover, a few relied on smoking as a coping strategy to relieve negative emotions and stress. Additionally, a few smokers had misconceptions about giving up: that a loss of concentration would result, that continued smoking would not further affect their health as they had become desensitised to the chemicals in tobacco smoke or that quitting would harm their health.

CONCLUSIONS

This study generates new knowledge about the behavior, attitudes, and experiences related to smoking of current female smokers, ex-smokers and non-smokers in Hong Kong, which is unique as a Chinese but highly westernized community but with a very low female smoking prevalence.

An individual risk prediction model for lung cancer based on a study in a Chinese population

AIMS AND BACKGROUND

Early detection and diagnosis remains an effective yet challenging approach to improve the clinical outcome of patients with cancer. Low-dose computed tomography screening has been suggested to improve the diagnosis of lung cancer in high-risk individuals. To make screening more efficient, it is necessary to identify individuals who are at high risk.

METHODS AND STUDY DESIGN

We conducted a case-control study to develop a predictive model for identification of such high-risk individuals. Clinical data from 705 lung cancer patients and 988 population-based controls were used for the development and evaluation of the model. Associations between environmental variants and lung cancer risk were analyzed with a logistic regression model. The predictive accuracy of the model was determined by calculating the area under the receiver operating characteristic curve and the optimal operating point.

RESULTS

Our results indicate that lung cancer risk factors included older age, male gender, lower education level, family history of cancer, history of chronic obstructive pulmonary disease, lower body mass index, smoking cigarettes, a diet with less seafood, vegetables, fruits, dairy products, soybean products and nuts, a diet rich in meat, and exposure to pesticides and cooking emissions. The area under the curve was 0.8851 and the optimal operating point was obtained. With a cutoff of 0.35, the false positive rate, true positive rate, and Youden index were 0.21, 0.87, and 0.66, respectively.

CONCLUSIONS

The risk prediction model for lung cancer developed in this study could discriminate high-risk from low-risk individuals.

Respiratory risks from household air pollution in low and middle income countries

A third of the world's population uses solid fuel derived from plant material (biomass) or coal for cooking, heating, or lighting. These fuels are smoky, often used in an open fire or simple stove with incomplete combustion, and result in a large amount of household air pollution when smoke is poorly vented. Air pollution is the biggest environmental cause of death worldwide, with household air pollution accounting for about 3·5-4 million deaths every year. Women and children living in severe poverty have the greatest exposures to household air pollution. In this Commission, we review evidence for the association between household air pollution and respiratory infections, respiratory tract cancers, and chronic lung diseases. Respiratory infections (comprising both upper and lower respiratory tract infections with viruses, bacteria, and mycobacteria) have all been associated with exposure to household air pollution. Respiratory tract cancers, including both nasopharyngeal cancer and lung cancer, are strongly associated with pollution from coal burning and further data are needed about other solid fuels. Chronic lung diseases, including chronic obstructive pulmonary disease and bronchiectasis in women, are associated with solid fuel use for cooking, and the damaging effects of exposure to household air pollution in early life on lung development are yet to be fully described. We also review appropriate ways to measure exposure to household air pollution, as well as study design issues and potential effective interventions to prevent these disease burdens. Measurement of household air pollution needs individual, rather than fixed in place, monitoring because exposure varies by age, gender, location, and household role. Women and children are particularly susceptible to the toxic effects of pollution and are exposed to the highest concentrations. Interventions should target these high-risk groups and be of sufficient quality to make the air clean. To make clean energy available to all people is the long-term goal, with an intermediate solution being to make available energy that is clean enough to have a health impact.

Household ventilation may reduce effects of indoor air pollutants for prevention of lung cancer: a case-control study in a Chinese population

Background

Although the International Agency for Research on Cancer (IARC) has classified various indoor air pollutants as carcinogenic to humans, few studies evaluated the role of household ventilation in reducing the impact of indoor air pollutants on lung cancer risk.

Objectives

To explore the association between household ventilation and lung cancer.

Methods

A population-based case-control study was conducted in a Chinese population from 2003 to 2010. Epidemiologic and household ventilation data were collected using a standardized questionnaire. Unconditional logistic regression was employed to estimate adjusted odds ratios (OR_adj) and their 95% confidence intervals (CI).

Results

Among 1,424 lung cancer cases and 4,543 healthy controls, inverse associations were observed for good ventilation in the kitchen (OR_adj = 0.86, 95% CI: 0.75, 0.98), bedroom (OR_adj = 0.90, 95% CI: 0.79, 1.03), and both kitchen and bedroom (OR_adj = 0.87, 95% CI: 0.75, 1.00). Stratified analyses showed lung cancer inversely associated with good ventilation among active smokers (OR_adj = 0.85, 95% CI: 0.72, 1.00), secondhand smokers at home (OR_adj = 0.77, 95% CI: 0.63, 0.94), and those exposed to high-temperature cooking oil fumes (OR_adj = 0.82, 95% CI: 0.68, 0.99). Additive interactions were found between household ventilation and secondhand smoke at home as well as number of household pollutant sources.

Conclusions

A protective association was observed between good ventilation of households and lung cancer, most likely through the reduction of exposure to indoor air pollutants, indicating ventilation may serve as one of the preventive measures for lung cancer, in addition to tobacco cessation.

Human papilloma virus detection and typing in 334 lung cancer patients

BACKGROUND

Unlike cervical, anogenital and oropharyngeal cancers, where high-risk human papillomavirus (hrHPV) has long been known to play a major role, a causative link between HPV and lung cancer has been investigated for decades with discrepant results.

METHODS

Lung cancer patients eligible for surgical treatment were tested for the presence of HPV-DNA in excised, fresh frozen lung tumor tissue. Patients that tested positive were further examined for the presence of HPV-DNA in adjacent normal lung parenchyma. HPV detection and genotyping was performed using a polymerase chain reaction (PCR)-based approach and allowed the typing of 13 "high-risk"-HPV-types and 2 "low-risk"-HPV-types.

RESULTS

Of the 334 tumor-DNA samples tested, 13 (3.9%) showed presence of HPV-DNA, of which 12 were of a high-risk HPV type (16, 33, 66). In those tested positive, HPV-DNA was not found in adjacent normal lung tissue. No correlation with smoking or EGFR/KRAS mutation status was seen, and only one of 84 squamous cell carcinomas was HPV-positive.

CONCLUSION

We conclude that HPV is rarely associated with lung cancer in a Northern European population and in those tested positive, more functional studies are required to determine the role HPV plays in lung cancer oncogenesis.

Cooking oil fumes and lung cancer: a review of the literature in the context of the U.S. population

There is growing evidence that exposure to cooking oil fumes (COF) is linked to lung cancer. Existing literature on this risk was reviewed, specifically as it may relate to potentially at-risk populations such as Chinese immigrants and restaurant workers in the United States. Studies were identified by searching the NCBI database with key terms. All studies that examined the significance, prevalence, and/or mechanism(s) of the association between COF exposure and cancer (all types) were included. A majority of epidemiologic studies found associations between lung cancer and COF exposure. All studies that examined the mechanisms underlying the risk found evidence for mutagenic and/or carcinogenic compounds in COF extract and/or molecular mechanisms for COF-induced DNA damage or carcinogenesis. The evidence reviewed underscores the need to thoroughly investigate the association among at-risk groups in the United States, as well as to develop and assess concrete interventions to reduce these risks.

Indoor aerosols: from personal exposure to risk assessment

Motivated by growing considerations of the scale, severity, and risks associated with human exposure to indoor particulate matter, this work reviewed existing literature to: (i) identify state-of-the-art experimental techniques used for personal exposure assessment; (ii) compare exposure levels reported for domestic/school settings in different countries (excluding exposure to environmental tobacco smoke and particulate matter from biomass cooking in developing countries); (iii) assess the contribution of outdoor background vs indoor sources to personal exposure; and (iv) examine scientific understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident activities, source events and site specificity, and highlights the importance of indoor sources for total personal exposure. Further, it was assessed that 10-30% of the total burden of disease from particulate matter exposure was due to indoor-generated particles, signifying that indoor environments are likely to be a dominant environmental factor affecting human health. However, due to challenges associated with conducting epidemiological assessments, the role of indoor-generated particles has not been fully acknowledged, and improved exposure/risk assessment methods are still needed, together with a serious focus on exposure control.

Indoor air pollution and risk of lung cancer among Chinese female non-smokers

PURPOSE

To investigate indoor particulate matter (PM) level and various indoor air pollution exposure, and to examine their relationships with risk of lung cancer in an urban Chinese population, with a focus on non-smoking women.

METHODS

We conducted a case-control study in Taiyuan, China, consisting of 399 lung cancer cases and 466 controls, of which 164 cases and 218 controls were female non-smokers. Indoor PM concentrations, including PM(1), PM(2.5), PM(7), PM(10), and TSP, were measured using a particle mass monitor. Unconditional logistic regression models were used to calculate odds ratios (ORs) and 95 % confidence intervals after adjusting for age, education, annual income, and smoking.

RESULTS

Among non-smoking women, lung cancer was strongly associated with multiple sources of indoor air pollution 10 years ago, including heavy exposure to environmental tobacco smoke at work (aOR = 3.65), high frequency of cooking (aOR = 3.30), and solid fuel usage for cooking (aOR = 4.08) and heating (aOR(coal stove) = 2.00). Housing characteristics related to poor ventilation, including single-story, less window area, no separate kitchen, no ventilator, and rarely having windows open, are associated with lung cancer. Indoor medium PM(2.5) concentration was 68 μg/m(3), and PM(10) was 230 μg/m(3). PM levels in winter are strongly correlated with solid fuel usage for cooking, heating, and ventilators. PM(1) levels in cases are more than 3 times higher than that in controls. Every 10 μg/m(3) increase in PM(1) is associated with 45 % increased risk of lung cancer.

CONCLUSIONS

Indoor air pollution plays an important role in the development of lung cancer among non-smoking Chinese women.

Occupational exposures and mortality from cardiovascular disease among women textile workers in Shanghai, China

BACKGROUND

Exposure to textile fiber dusts, like particulate air pollution, may be associated with cardiovascular disease (CVD) mortality. Bacterial endotoxin, a potent inflammagen found in cotton dust, may be a specific risk factor.

METHODS

Female textile workers (N = 267,400) in Shanghai, China were followed for CVD mortality (1989-2000). Factory exposures were approximated by sector classifications based on materials and processes. Quantitative endotoxin and cotton dust measures were available for a subcohort (n = 3,188). Cox proportional hazards modeling was used to estimate hazard ratios (HR) and 95% confidence interval (CI).

RESULTS

Slightly elevated mortality risk for the cotton sector was seen for ischemic stroke (HR = 1.12, 95% CI: 0.97-1.31) and hemorrhagic stroke (HR = 1.12, 95% CI: 1.02-1.23). Similar hemorrhagic stroke mortality risk was observed in high dust sectors (HR = 1.12, 95% CI: 1.02-1.24). No association was observed for ischemic heart disease.

CONCLUSIONS

Exposures in textile factories may have contributed to CVD mortality among this cohort. The specific components of these exposures that may be harmful are not clear and should be further investigated.

Smoking and air pollution exposure and lung cancer mortality in Zhaoyuan County

BACKGROUND

Simultaneous exposure to high levels of air pollution and high tobacco consumption at the same place is rare. The aim of the present study was to evaluate the impact of the two factors on the risk of developing lung cancer.

METHODS

Data on the number of deaths due to lung cancer and on population from 1970 to 2009 were obtained from Zhaoyuan County. Data on the smoking populations were obtained at random sampling survey during the time in Zhaoyuan. Data on the components of atmospheric surveillance were obtained from the local environmental protection offices. Logarithmic linear regression and general log-linear Poisson age-period-cohort (APC) models were used to estimate age, period, cohort, gender, smoking, and air pollution effects on the risk of lung cancer mortality.

RESULTS

The standardized mortality rates of lung cancer drastically increased from 8.43 in per 100 000 individuals in the 1970-1974 to 25.67 in per 100 000 individuals in the 2005-2009 death survey. The annual change of lung cancer mortality was 3.20%. In the log linear regression model, the age, proportion of smokers, gender, period, and air pollution are significantly associated with lung cancer mortality. The APC analysis shows that the relative risks (RRs) of gender, smoking, and air pollution are 2.29 (95% confidence interval (CI): 2.16-2.43), 3.05 (95% CI = 2.76-3.36), and 1.42 (95% CI = 1.19-1.69), respectively. Compared with the period 1970-1974, high RRs were found during 1995-2009. Compared with the birth cohort 1950-1954, the RRs increased in the birth cohorts of 1910 to the 1940. Compared the aged 35-59 and 60-84 in the 1980-1984 death survey (not exposed to air pollution) with that in the 2005-2009 death survey (exposed to air pollution), The two age groups exposed to air pollution, 25 years later, had an increased mortality rates for lung cancer by 2.27 and 3.55 times for males and by 1.47 and 3.35 times for females.

CONCLUSION

The mortality rates of lung cancer drastically increased in the past 35 years. The trend of lung cancer mortality may be in a great extent possibly due to the effects of combined smoking and air pollution exposure.

What proportion of lung cancer in never-smokers can be attributed to known risk factors?

Though tobacco smoking is the primary risk factor for lung cancer, a significant fraction of lung cancer deaths occur in lifetime nonsmokers. In this article, we calculate the burden of lung cancer in never-smokers attributable to previously identified risk factors in North America, Europe and China, using population-based estimates of exposure prevalence and estimates of relative risk derived from recently published meta-analyses. Population attributable fractions (PAFs) for individual risk factors ranged from 0.40 to 19.93%. Because of differences in the prevalence of exposures, the PAFs associated with several of the risk factors varied greatly by geographical region. Exposure to the selected risk factors appeared to explain a much larger proportion of lung cancer cases in never-smokers in China than in Europe and North America. Our results demonstrate the geographic variability of the epidemiology of lung cancer in never-smokers and highlight the need for further research in this area, particularly in Europe and North America.

Chapter 6: Lung cancer in never smokers: epidemiology and risk prediction models

In this chapter we review the epidemiology of lung cancer incidence and mortality among never smokers/nonsmokers and describe the never smoker lung cancer risk models used by the Cancer Intervention and Surveillance Network (CISNET) modelers. Our review focuses on those influences likely to have measurable population impact on never smoker risk, such as secondhand smoke, even though the individual-level impact may be small. Occupational exposures may also contribute importantly to the population attributable risk of lung cancer. We examine the following risk factors in this chapter: age, environmental tobacco smoke, cooking fumes, ionizing radiation including radon gas, inherited genetic susceptibility, selected occupational exposures, preexisting lung disease, and oncogenic viruses. We also compare the prevalence of never smokers between the three CISNET smoking scenarios and present the corresponding lung cancer mortality estimates among never smokers as predicted by a typical CISNET model.

Cell type specificity of female lung cancer associated with sulfur dioxide from air pollutants in Taiwan: an ecological study

Background

Many studies have examined the association between air pollutants (including sulfur dioxide [SO₂], carbon monoxide [CO], nitrogen dioxide [NO₂], nitric oxide [NO], ozone [O₃], and particulate matter < 10 μm [PM₁₀]) and lung cancer. However, data from previous studies on pathological cell types were limited, especially for SO₂ exposure. We aimed to explore the association between SO₂ exposure from outdoor air pollutants and female lung cancer incidence by cell type specificity.

Methods

We conducted an ecological study and calculated annual average concentration of 6 air pollutants (SO₂, CO, NO₂, NO, O₃, and PM₁₀) using data from Taiwan Environmental Protection Administration air quality monitoring stations. The Poisson regression models were used to evaluate the association between SO₂ and age-standardized incidence rate of female lung cancer by two major pathological types (adenocarcinoma [AC] and squamous cell carcinoma [SCC]). In order to understand whether there is a dose-response relationship between SO₂ and two major pathological types, we analyzed 4 levels of exposure based on quartiles of concentration of SO₂.

Results

The Poisson regression results showed that with the first quartile of SO₂ concentration as the baseline, the relative risks for AC/SCC type cancer among females were 1.20 (95% confidence interval [CI], 1.04-1.37)/1.39 (95% CI, 0.96-2.01) for the second, 1.22 (95% CI, 1.04-1.43)/1.58 (95% CI, 1.06-2.37) for the third, and 1.27 (95% CI, 1.06-1.52)/1.80 (95% CI, 1.15-2.84) for the fourth quartile of SO₂ concentration. The tests for trend were statistically significant for both AC and SCC at P = 0.0272 and 0.0145, respectively.

Conclusion

The current study suggests that SO₂ exposure as an air pollutant may increase female lung cancer incidence and the associations with female lung cancer is much stronger for SCC than for AC. The findings of this study warrant further investigation on the role of SO₂ in the etiology of SCC.

Interaction of cigarette exposure and airway epithelial cell gene expression

Cigarette smoking is responsible for lung cancer and chronic obstructive pulmonary disease (COPD), the leading cause of death from cancer and the second-leading cause of death in the United States. In the United States, 46 million people smoke, with an equal number of former smokers. Moreover, 20-25% of current or former smokers will develop either disease, and smokers with one disease are at increased risk for developing the other. There are no tools for predicting risk of developing either disease; no accepted tools for early diagnosis of potentially curable lung cancer; and no tools for defining molecular pathways or molecular subtypes of these diseases, for predicting rate of progression, or for assessing response to therapy at a biochemical or molecular level. This review discusses current studies and the future potential of measuring global gene expression in epithelial cells that are in the airway field of injury and of using the genomic information derived to begin to answer some of the above questions.

The precancerous effect of emitted cooking oil fumes on precursor lesions of cervical cancer

Although cooking emission from high-temperature frying has been deemed a Group 2A carcinogen by the International Agency for Research on Cancer, little is known about its impact on cervical tumorigenesis. To investigate the precancerous consequence of cooking oil fumes on cervical intraepithelial neoplasm (CIN), a community-based case-control study, which takes all known risk factors into consideration, was conducted in Taiwan. From 2003 to 2008, in a Pap smear screening and biopsy examination network, 206 pathology-verified women with inflammations/atypical squamous cells of undetermined significance or CIN grade-1 (CIN1) and 73 with CIN2-3 (defined as low-grade squamous intraepithelial lesions (LGSIL) and high-grade squamous intraepithelial lesions (HGSIL), respectively); and 1,200 area-and-age-matched controls with negative cytology were recruited. Multinomial logistic regression was applied in the multivariate analysis to determine the likelihood of contracting LGSIL or HGSIL. The risks of the two lesions increased with the increase of carcinogenic high-risk human papillomavirus DNA load, with a clear dose-response relationship. Chefs were observed to experience a 7.9-fold elevated HGSIL risk. Kitchens with poor fume ventilation during the main cooking life-stage correlated to a 3.7-fold risk of HGSIL, but not for LGSIL. More than 1 hr of daily cooking in kitchens with poor fume conditions appeared to confer an 8.4-fold HGSIL risk, with an 8.3-fold heterogeneously higher odds ratio than that (aOR = 1.0) for LGSIL. Similar risk pattern has been reproduced among never-smoking women. Our findings demonstrate the association between indoor exposure to cooking fumes from heated oil and the late development of cervical precancerous lesions. This final conclusion needs to be verified by future research.

Elevated levels of volatile organic carcinogen and toxicant biomarkers in Chinese women who regularly cook at home

BACKGROUND

Epidemiologic studies associate lung cancer in nonsmoking Chinese women with Chinese-style wok cooking. Our goal was to quantify carcinogen and toxicant biomarkers in Chinese women who reported regularly doing home cooking compared with women randomly selected from the Singapore Chinese Health Study as controls.

METHODS

Biomarkers were quantified by high-performance liquid chromatography-mass spectrometry, high-performance liquid chromatography with fluorescence detection, and gas chromatography-mass spectrometry.

RESULTS

Compared with controls, women who engaged in regular home cooking had significantly higher levels of mercapturic acids of acrolein {geometric mean, 1,959 pmol/mg creatinine [95% confidence interval (95% CI), 1,554-2,467] versus 1,370 (95% CI, 1,077-1,742); P=0.038}, crotonaldehyde [geometric mean, 232 pmol/mg creatinine (95% CI, 193-277) versus 142 (95% CI, 118-171); P=0.0004], and benzene [geometric mean, 0.58 pmol/mg creatinine (95% CI, 0.44-0.78) versus 0.18 (95% CI, 0.14-0.24); P<0.0001]. No significant differences were found in levels of mercapturic acids of 1,3-butadiene, metabolites of pyrene and phenanthrene, or acetaldehyde-leukocyte DNA adduct levels between the groups. Levels of the ethylene oxide mercapturic acid were significantly higher in the controls.

CONCLUSIONS

The higher levels of the mercapturic acid of benzene, a multiorgan carcinogen, in the women who cooked are particularly notable. Overall, the results showing increased exposure to the volatile toxicants and carcinogens acrolein, crotonaldehyde, and benzene in Chinese women who regularly cook provide a plausible lead for further investigating the role of volatile compounds generated during high-temperature cooking with oils as causes of lung cancer.

IMPACT

A new direction for research on lung cancer etiology is suggested.

Risk factors for lung cancer: a case-control study in Hong Kong women

To identify etiological connections of lung cancer in Chinese women in Hong Kong, who are among the highest in lung cancer incidence and mortality, we conducted a case-control study, in which 279 female lung cancer cases and 322 controls were selected and frequency matched. A variety of information, including dietary habits, occupational history, smoking, domestic environmental exposures, and family history of cancer was collected, and their associations with lung cancer were analyzed with logistic analysis approach. In addition to positive associations with exposures to cooking emissions and to radon at home, smoking and family cancer history, we observed that increasing consumption of meat was linked to a higher risk, whereas consumptions of vegetables had a strong protective effect against lung cancer. Moderate consumption of coffee appeared to be beneficial against the disease. Those never employed and domestic helpers were at a higher risk. The results indicated that environmental exposures, risky personal behaviors, or lifestyle, as well as family cancer aggregation are among important contributors to the high incidence of lung cancer in Hong Kong females.

ERCC2, ERCC1 polymorphisms and haplotypes, cooking oil fume and lung adenocarcinoma risk in Chinese non-smoking females

BACKGROUND

Excision repair cross-complementing group 1 (ERCC1) and group 2 (ERCC2) proteins play important roles in the repair of DNA damage and adducts. Single nucleotide polymorphisms (SNPs) of DNA repair genes are suspected to influence the risk of lung cancer. This study aimed to investigate the association between the ERCC2 751, 312 and ERCC1 118 polymorphisms and the risk of lung adenocarcinoma in Chinese non-smoking females.

METHODS

A hospital-based case-control study of 285 patients and 285 matched controls was conducted. Information concerning demographic and risk factors was obtained for each case and control by a trained interviewer. After informed consent was obtained, each person donated 10 ml blood for biomarker testing. Three polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

This study showed that the individuals with the combined ERCC2 751AC/CC genotypes were at an increased risk for lung adenocarcinoma compared with those carrying the AA genotype [adjusted odds ratios (OR) 1.64, 95% confidence interval (CI) 1.06-2.52]. The stratified analysis suggested that increased risk associated with ERCC2 751 variant genotypes (AC/CC) was more pronounced in individuals without exposure to cooking oil fume (OR 1.98, 95%CI 1.18-3.32) and those without exposure to fuel smoke (OR 2.47, 95%CI 1.46-4.18). Haplotype analysis showed that the A-G-T and C-G-C haplotypes were associated with increased risk of lung adenocarcinoma among non-smoking females (ORs were 1.43 and 2.28, 95%CIs were 1.07-1.91 and 1.34-3.89, respectively).

CONCLUSION

ERCC2 751 polymorphism may be a genetic risk modifier for lung adenocarcinoma in non-smoking females in China.