Secondhand smoke exposure predicted COPD and other tobacco-related mortality in a 17-year cohort study in China

Secondhand smoke increases the risk of developing chronic obstructive pulmonary disease

Smoking is the most important risk factor for chronic obstructive pulmonary disease (COPD), however evidence from large-scale studies on whether secondhand smoke (SHS) increases the risk of COPD is still lacking. We conducted this large longitudinal study to investigate the association between SHS and the development of COPD. This is a longitudinal study. Data on 6519 subjects who were never-smokers, had no history of COPD, and had complete lung function records were extracted from the Taiwan Biobank. They were divided into two groups according to SHS exposure: no exposure and exposure groups. Data were collected when participants enrolled in the study and during regular follow-up. Cox proportional hazards regression models were used to estimate the relative risk (RR) and 95% confidence interval (CI) for the association between SHS and the risk of developing COPD. At 48 months of follow-up, 260 (4%) participants in the no exposure group and 34 (7%) participants in the exposure group developed COPD. The RR of incident COPD development was significantly higher in the exposure group than that in the no exposure group after adjusting for confounders (RR = 1.49; 95% CI 1.04 to 2.14; P value = 0.031). There is a dose-response relationship between the duration of exposure to SHS and the risk of incident COPD, which demonstrates that an additional hour of exposure to SHS per week was associated with a 1.03-fold increased likelihood of developing COPD after adjusting for confounders (RR = 1.03; 95% CI 1.00 to 1.05; P value = 0.027). SHS exposure contributes to the development of COPD. This finding can help raise awareness of the harms of SHS and provide a reference for formulating anti-smoking policies.

GSTP1 rs4147581 C>G and NLRP3 rs3806265 T>C as Risk Factors for Chronic Obstructive Pulmonary Disease: A Case-Control Study

Background

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory ailment influenced by a blend of genetic and environmental factors. Inflammatory response and an imbalance in oxidative-antioxidant mechanisms constitute the primary pathogenesis of COPD. Glutathione S-transferase P1(GSTP1) plays a pivotal role as an antioxidant enzyme in regulating oxidative-antioxidant responses in the pulmonary system. The activation of the NOD-like receptor thermal protein domain (NLRP3) inflammatory vesicle can trigger an inflammatory response. Several investigations have implicated GSTP1 and NLRP3 in the progression of COPD; nonetheless, there remains debate regarding this mechanism.

Methods

Employing a case-control study design, 312 individuals diagnosed with COPD and 314 healthy controls were recruited from Gansu Province to evaluate the correlation between GSTP1 (rs4147581C>G and rs1695A>G) and NLRP3 (rs3806265T>C and rs10754558G>C) polymorphisms and the susceptibility to COPD.

Results

The presence of the GSTP1 rs4147581G allele substantially elevated the susceptibility to COPD (CGvs.CC:OR=3.11,95% CI=1.961-4.935, P<0.001;GGvs.CC:OR=2.065,95% CI=1.273-3.350, P=0.003; CG+GGvs.CC:OR=2.594,95% CI=1.718-3.916, P<0.001). Similarly, the NLRP3rs3806265T allele significantly increased the susceptibility to COPD (TC:TT:OR=0.432,95% CI=0.296-0.630; TC+CCvs.TT:OR=2.132,95% CI=1.479-3.074, P<0.001). However, no statistically significant association was discerned between the rs1695A>G and rs10754558G>C polymorphisms and COPD susceptibility (P>0.05).

Conclusion

In summary, this study ascertained that the GSTP1 rs4147581C>G polymorphism is associated with increased COPD susceptibility, with the G allele elevating the risk of COPD. Similarly, the NLRP3 rs3806265T>C polymorphism is linked to elevated COPD susceptibility, with the T allele heightening the risk of COPD.

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.

An investigation of the risk factors of chronic obstructive pulmonary disease in natural population-based cohorts in China - a nested case-control study

Background

Chronic obstructive pulmonary disease (COPD) has become one of the most significant chronic diseases in China. According to conventional wisdom, smoking is the pathogenic factor. However, current research indicates that the pathophysiology of COPD may be associated with prior respiratory system events (e.g., childhood hospitalization for pneumonia, chronic bronchitis) and environmental exposure (e.g., dust from workplace, indoor combustion particles). Dyspnea, persistent wheezing, and other respiratory symptoms further point to the need for pulmonary function tests in this population. Reducing the burden of chronic diseases in China requires a thorough understanding of the various factors that influence the occurrence of COPD.

Methods

Using a cohort from the natural population, this study used nested case-control analysis. We carried out a number of researches, including questionnaire surveys and pulmonary function testing, in the Northwest and Southeast cohorts of China between 2014 and 2021. After removing any variations in the baseline data between patients and control subjects using propensity score matching analysis, the risk factors were examined using univariate or multivariate regression.

Result

It was discovered that prior history of chronic bronchitis, long-term wheezing symptoms, and environmental exposure-including smoking and biofuel combustion-were risk factors for COPD. Dyspnea, symptoms of mobility limitation, organic matter, and a history of hospitalization for pneumonia at an early age were not significant in the clinical model but their incidence in COPD group is higher than that in healthy population.

Discussion

COPD screening effectiveness can be increased by looking for individuals with chronic respiratory symptoms. Smokers should give up as soon as they can, and families that have been exposed to biofuels for a long time should convert to clean energy or upgrade their ventilation. Individuals who have previously been diagnosed with emphysema and chronic bronchitis ought to be extra mindful of the prevention or advancement of COPD.

Current Progress of COPD Early Detection: Key Points and Novel Strategies

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide, with approximately 70% to 80% of adults with COPD being undiagnosed. Patients with undiagnosed COPD are at increased risk of poor outcomes and a worsened quality of life, making early detection a crucial strategy to mitigate the impact of COPD and reduce the burden on healthcare systems. In the past decade, increased interest has been focused on the development of effective strategies and instrument for COPD early detection. However, identifying undiagnosed cases of COPD is still challenging. Both screening and case-finding approaches have been adopted to identify undiagnosed COPD, with case-finding being recommended by the 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) guideline and the updated United States Preventive Services Task Force (USPTF) recommendation. Nonetheless, the approaches, criteria, and instruments used for early detection of COPD are varied. However, advances in the taxonomy and risk factors of COPD are continuously being investigated. It is important to continuously assess the current state of knowledge on COPD early detection, given the challenges associated with identifying undiagnosed COPD. This review aims to highlight recent advances in early detection of COPD. To discuss the current challenge and opportunity in COPD early detection, providing an overview of existing literature on COPD case-finding strategies, including the approaches, criteria for subjects, and instruments. The review also summarizes the current progress in COPD case-findings and proposes a COPD case-finding flowchart as an efficient method for identifying at risk COPD patients.

Secondhand smoke, genetic susceptibility, and incident chronic kidney disease in never smokers: A prospective study of a selected population from the UK Biobank

INTRODUCTION

A large number of people around the world are exposed to the risks of passive smoking. This prospective study aimed to examine the association between secondhand smoke exposure, exposure time, and the incidence of chronic kidney disease (CKD) and determine whether this association was influenced by genetic susceptibility.

METHODS

The study included 214244 participants of the UK Biobank who were initially free of CKD. Cox proportional hazards model was used to estimate the associations between secondhand smoke exposure time and the risks of CKD in people who have never smoked. The genetic risk score for CKD was calculated by a weighted method. The likelihood ratio test comparing models was used to examine the cross-product term between secondhand smoke exposure and genetic susceptibility to CKD outcomes.

RESULTS

During a median of 11.9 years of follow-up, 6583 incidents of CKD were documented. Secondhand smoke exposure increased the risk of CKD (HR=1.09; 95% CI: 1.03-1.16, p<0.01), and a dose-response relationship between CKD prevalence and secondhand smoke exposure time was found (p for trend<0.01). Secondhand smoke exposure increases the risk of CKD even in people who never smoke and have a low genetic risk (HR=1.13; 95% CI: 1.02-1.26, p=0.02). There was no statistically significant interaction between secondhand smoke exposure and genetic susceptibility to CKD (p for interaction=0.80).

CONCLUSIONS

Secondhand smoke exposure is associated with higher risk of CKD, even in people with low genetic risk, and the relationship is dose dependent. These findings change the belief that people with low genetic susceptibility and without direct participation in smoking activities are not prone to CKD, emphasizing the need to avoid the harm of secondhand smoke in public places.

Residential secondhand smoke in a densely populated urban setting: a qualitative exploration of psychosocial impacts, views and experiences

Background

People remain exposed to secondhand smoke, a serious health hazard, inside their home as households face challenges in setting no-smoking rules or are exposed to secondhand smoke drifting in from neighbouring homes. This study explores the psychosocial impacts, views, and experiences with residential secondhand smoke in a densely populated urban setting. 

Methods

In-depth online or face to face interviews with 18 key informants who had been involved in public discourse, policy, advocacy or handling complaints related to residential secondhand smoke, 14 smokers, and 16 non-smokers exposed to secondhand smoke inside their home. All participants were residents of Singapore, a densely populated, multi-ethnic city-state. Interview transcripts were coded in NVivo using a deductive and inductive coding process.

Findings

Secondhand smoke has wide-reaching impacts on physical and psychosocial wellbeing, even if smokers tried to minimise secondhand smoke. Feelings of anxiety and stress are generally tied to feeling discomfort in one’s personal space, a perceived lack of control over the situation, resentment towards smokers, and concerns over the health effects. Family, community, and cultural dynamics add complexities to tackling the issue, especially in patriarchal households. Secondhand smoke exposure from neighbours is considered a widespread issue, exacerbated by structural factors such as building layout and the COVID-19 pandemic. Resolving the issue amicably is considered challenging due to the absence of regulations and a reluctance to stir up conflict with neighbours. While smokers took measures to reduce secondhand smoke, these were described as ineffective by other participants. Smokers appeared to have contrasting views from other participants on what it means to smoke in a socially responsible manner.

Conclusion

Given the wide-reaching psychosocial impacts of residential secondhand smoke, there is a case for stronger interventions, especially in densely populated urban settings where it is more difficult to avoid.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13561-7.

Chronic obstructive pulmonary disease in never-smokers: risk factors, pathogenesis, and implications for prevention and treatment

Chronic obstructive pulmonary disease (COPD) was traditionally thought to be caused by tobacco smoking. However, recognition of the importance of non-smoking-related risk factors for COPD has increased over the past decade, with evidence on the burden, risk factors, and clinical presentations of COPD in never-smokers. About half of all COPD cases worldwide are due to non-tobacco-related risk factors, which vary by geographical region. These factors include air pollution, occupational exposures, poorly controlled asthma, environmental tobacco smoke, infectious diseases, and low socioeconomic status. Impaired lung growth during childhood, caused by a range of early-life exposures, is associated with an increased risk of COPD. Potential mechanisms for the pathogenesis of COPD in never-smokers include inflammation, oxidative stress, airway remodelling, and accelerated lung ageing. Compared with smokers who develop COPD, never-smokers with COPD have relatively mild chronic respiratory symptoms, little or no emphysema, milder airflow limitation, and fewer comorbidities; however, exacerbations can still be frequent. Further research-including epidemiological, translational, clinical, and implementation studies-is needed to address gaps in understanding and to advance potential solutions to reduce the burden of COPD in never-smokers.

The changes of MRP2 expression in three kinds of pulmonary inflammation models: the downregulation occurred in cigarette smoke extract (CSE) stimulation group and CSE plus LPS stimulation group, unchanged in LPS stimulation group

The transporter multidrug resistance protein 2 (MRP2) can transport some tobacco carcinogens and plays an important role in the transport of mediators related to pulmonary inflammatory diseases. However, it is not fully understood whether the pulmonary inflammation caused by cigarette smoke extract (CSE) and lipopolysaccharide (LPS) is related to the regulation of MRP2. In this study, CSE and LPS were used alone and in combination as stimuli to induce pulmonary inflammation. In addition, the establishment of a pulmonary inflammation model was verified by animal experiments in vivo. We found that compared with those in the control group, the expression of MRP2 protein was downregulated and the expression of inflammatory cytokines was upregulated in pulmonary inflammation in the CSE group and the CSE combined with LPS group. However, there was almost no change in the expression of MRP2 stimulated by LPS alone. Our results show that CSE and CSE combined with LPS downregulate the expression of MRP2 under inflammatory conditions, while LPS has almost no effect on the expression of MRP2 under inflammatory conditions. The in vivo experimental results of CSE combined with LPS were consistent with the cellular results of CSE combined with LPS, which provides a model and basis for other studies of the role of MRP2 in pulmonary inflammation.

Current status and preventive strategies of chronic obstructive pulmonary disease in China: a literature review

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease that seriously threatens human health and wellbeing, thereby representing an important public health problem. At present, it is the fourth leading cause of death worldwide, and is estimated to become the third greatest cause of death by 2030. In China, the prevalence of COPD is increasing, secondary to an increase in smoking, air pollution and an aging population, resulting in a current the mortality of COPD in China which is higher than the global average. Moreover, the disability-adjusted life year (DALY) rate of COPD in China is still relatively high, with an associated heavy economic burden to patients, their families and society. Unfortunately, current measures for treatment and prevention of COPD in China are not optimal. This primarily results from limited public awareness of COPD and pulmonary function tests amongst residents of China, and the generally poor disease-specific knowledge of primary care doctors. In recent years, a series of preventative strategies have been introduced in China across at the level of national policy, societies and associations, and scientific research. This review focuses upon both the epidemiology of COPD and the current status of preventative and treatment strategies in China.

Burden of disease from second-hand tobacco smoke exposure at home among adults from European Union countries in 2017: an analysis using a review of recent meta-analyses

Smoke-free legislation reduced second-hand smoke (SHS) exposure in public places, and indirectly promoted private smoke-free settings. Nevertheless, a large proportion of adults is still exposed to SHS at home. The aim of this paper is to quantify the burden of disease due to home SHS exposure among adults in the 28-European Union (EU) countries for year 2017. The burdens by gender from lung cancer, chronic obstructive pulmonary disease (COPD), breast cancer, ischemic heart disease (IHD), stroke, asthma, and diabetes were estimated in an original research analysis using the comparative risk assessment method. Relative risks of death/diseases by gender for adults exposed to SHS at home compared to not exposed ones were estimated updating existing meta-analyses. Prevalence of home SHS exposure by gender was estimated using a multiple imputation procedure based on Eurobarometer surveys. Data on mortality and disability adjusted life years (DALYs) were obtained from the Global Burden of Disease, Injuries and Risk Factors Study. In 2017, 526,000 DALYs (0.36% of total DALYs) and 24,000 deaths (0.46% of total deaths) were attributable to home SHS exposure in the 28-EU countries, mainly from COPD and IHD. South-Eastern EU countries showed the highest burden, with proportion of DALYs/deaths attributable to SHS exposure on total higher than 0.50%/0.70%, whereas northern EU-countries showed the lowest burden, with proportions of DALYs/deaths lower than 0.25%/0.34%. The burden from SHS exposure is still significant in EU countries. More could be done to raise awareness of the health risks associated with SHS exposure at home.

Tobacco Use: A Major Risk Factor of Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhage (sICH) is one of the deadliest subtypes of stroke, and no treatment is currently available. One of the major risk factors is tobacco use. In this article, we review literature on how tobacco use affects the risk of sICH and also summarize the known effects of tobacco use on outcomes following sICH. Several studies demonstrate that the risk of sICH is higher in current cigarette smokers compared to non-smokers. The literature also establishes that cigarette smoking not only increases the risk of sICH but also increases hematoma growth, results in worse outcomes, and increases the risk of death from sICH. This review also discusses potential mechanisms activated by tobacco use which result in an increase in risk and severity of sICH. Exploring the underlying mechanisms may help alleviate the risk of sICH in tobacco users as well as may help better manage tobacco user sICH patients.

Environmental tobacco smoke and cancer risk, a prospective cohort study in a Chinese population

Few prospective cohort studies have investigated associations between environmental tobacco smoke (ETS) and other cancer sites, in addition to lung cancer. We assessed these associations in a population-based prospective cohort study started from 2008 to 2011 with average of 9.1 years of follow-up, in Minhang district, Shanghai, China. The study included a total of 23,415 participants (8388 men, 15,027 women) and 205,515 person-years. Epidemiological data were collected by a standardized questionnaire including ETS exposure. Newly diagnosed patients with primary cancers and deaths were identified by record linkage system with the Shanghai Cancer Registry and Shanghai Vital Statistics. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models, adjusting for potential confounders. During the study period, a total of 1462 patients with diagnoses of primary cancers were identified. Among all participants and non-smokers, ETS was associated with an increased risk of all smoking-related cancers (all: adjusted HR: 1.23, 95% CI: 1.05-1.43 and non-smokers: 1.24, 1.02-1.49), lung cancer (1.29, 0.98-1.71 and 1.27, 0.91-1.77), and stomach cancer (1.86, 1.21-2.85 and 1.75, 1.05-2.91), respectively. Furthermore, associations for lung and stomach cancers were the strongest among non-smoking females. The joint effects of both ETS and active smoking were strongest for all cancers, all smoking-related cancers, lung cancer, and stomach cancer. No clear interactions were observed. These results suggest that ETS exposure may increase the risk of smoking-related cancers in a Chinese population. Further studies on the relationship between ETS exposure and specific cancer sites are warranted to replicate our findings.

Neighborhood greenness associated with chronic obstructive pulmonary disease: A nationwide cross-sectional study in China

Differential findings have been reported on the association between neighborhood greenness and chronic obstructive pulmonary disease (COPD). The underlying reasons might be the different types of vegetation and the diagnosis methods used in different studies. In this nationwide cross-sectional study in China, we examined the linkage between neighborhood greenness and COPD prevalence among 66,752 adults aged 40 years and above. Neighborhood greenness was estimated using the normalized difference vegetation index (NDVI) based on satellite imagery within buffers of 100, 300, 500, 1000, 2000, 3000 and 5000 m of residential community of the participants. COPD was defined according to the 2017 Global Initiative for Chronic Obstructive Lung Disease lung function criteria. A two-level logistic regression model was applied to estimate the associations. Finally, 9134 adults were classified as COPD. We observed significant positive associations between neighborhood greenness and COPD prevalence. The odds ratio for each interquartile range increase in NDVI within 100 m buffer was 1.08 (95% CI: 1.01, 1.15) after adjustment for potential confounders. Consistent associations were observed across all other NDVI buffer sizes. Stratified analyses revealed that younger adults (40-65 years) and urban residents might be the vulnerable subpopulations. Further regional analyses found that residents from the Northeastern and Northern China were more likely to have this association. Our results indicated that neighborhood greenness might be one risk factor of COPD prevalence. Our study have important public health implications for allocating the surrounding green spaces among living areas, especially for those with respiratory illness; however, the findings and the underlying mechanisms warrant further examinations in longitudinal settings.

Trends in Disease Burden Attributable to Tobacco in China, 1990-2017: Findings From the Global Burden of Disease Study 2017

In 2018, there were more than 371 million cigarette smokers and 12. 6 million electronic cigarette users, with 340.2 million non-smokers exposed to secondhand smoke (SHS) in China, which resulted in heavy tobacco-attributable disease burden. According to the definition by the Global Burden of Disease Study 2017 (GBD 2017), tobacco is a level 2 risk factor that consists of three sublevel risk factors, namely, smoking, SHS, and chewing tobacco. In this study, we aimed to evaluate the trends in deaths and disability-adjusted life years (DALYs) attributable to tobacco, smoking, SHS, and chewing tobacco by sex in China from 1990 to 2017 and to explore the leading causes of tobacco-attributable deaths and DALYs using data from the GBD 2017. From 1990 to 2017, the tobacco-attributable death rates per 100,000 people decreased from 75.65 [95% uncertainty interval (95% UI) = 56.23-97.74] to 70.90 (95% UI = 59.67-83.72) in females and increased from 198.83 (95% UI = 181.39-217.47) to 292.39 (95% UI = 271.28-313.76) in males. From 1990 to 2017, the tobacco-attributable DALY rates decreased from 2209.11 (95% UI = 1678.63-2791.91) to 1489.05 (95% UI = 1237.65-1752.57) in females and increased from 5650.42 (95% UI = 5070.06-6264.39) to 6994.02 (95% UI = 6489.84-7558.41) in males. In 2017, the tobacco-attributable deaths in China were concentrated on chronic obstructive pulmonary disease, ischemic heart disease, lung cancer, and stroke. The focus of tobacco control for females was SHS in 1990, whereas smoking and SHS were equally important for tobacco control in females in 2017. Increasing tobacco taxes and prices may be the most effective and feasible measure to reduce tobacco-attributable disease burdens.

Second-Hand Smoke Exposure Among Coronary Heart Disease Patients

Purpose

The objectives of this study were to assess second-hand smoke (SHS) exposure among coronary heart disease (CHD) patients at home, in transportation, workplace, public and social places; to examine the demographic factors that predict SHS exposure; and to investigate the relationship between SHS exposure and CHD complications, age at the time of diagnosis, and number of admissions in the last year.

Patients and Methods

A descriptive cross-sectional design was used with a convenient sample of 400 CHD patients from three hospitals in Jordan. A modified version of the Smoking Scale for Adults (SS-A) was used.

Results

The percentage of SHS exposure was 64% in public places, 51.5% in social places, 48.5% in the household, 31% in transportation, while it was only 14.8% in the workplace. In addition, being male, employed, having a younger age and lower education significantly predicted higher exposure to SHS. Exposure to SHS was positively associated with CHD complications and the number of admissions, while it was negatively associated with the age at diagnosis with CHD.

Conclusion

Collaboration is needed among all health care sectors to adopt educational strategies about SHS exposure and to activate policies to prohibit smoking in public places.

PRDX5 as a novel binding partner in Nrf2-mediated NSCLC progression under oxidative stress

Non-small-cell lung cancer (NSCLC) is one of the most common malignant tumors in the world. Reactive oxidative species (ROS) and nuclear factor-related factor 2 (Nrf2) -antioxidant response element (ARE) signal pathway are known to play important roles in the development of NSCLC. In this study, we identified Peroxiredoxin 5 (PRDX5) as a novel binding partner for Nrf2. PRDX5 was significantly increased in human NSCLC specimens and cell lines. Nrf2 interacted with PRDX5 in H₂O₂-stimulated NCSLC cells, and the interaction promoted the expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) protein in NSCLC cells. Further, high expression of Nrf2 and PRDX5 were associated with worsened prognosis in patients with NSCLC significantly. Moreover, animal studies showed that the growth of tumors treated with Nrf2 and PRDX5 shRNA was significantly lower than that of the other groups. All these data indicated that overexpressed PRDX5 in NSCLC promoted binding with Nrf2 and enhanced NQO1 expression and NSCLC development. Overall, our studies demonstrated that PRDX5 can be a novel binding partner of Nrf2 in promoting NCSLC development under oxidative stress and provide potential opportunity for improving NSCLC therapy.

Promoting smoking cessation in China: a foot-in-the-door approach to tobacco control advocacy

INTRODUCTION

The Chinese government's implementation of the MPOWER policies and compliance with the WHO Framework Convention on Tobacco Control requirements has been slow. We used the 'foot-in-the-door' approach to promote tobacco control advocacy through capacity building of healthcare leaders, and establishment of smoking cessation clinics in Guangzhou and Beijing (two of the largest cities in China).

METHODS

This collaborative pilot project involved the University of Hong Kong and three major hospitals in Guangzhou and Beijing. A steering committee conducted the smoking cessation training workshops starting from April 2006, and set up three smoking cessation model clinics during August 2006 to October 2008. We followed up the trained health care professionals (HCPs) in 2014 and 2015 to assess their impacts on tobacco control beyond smoking cessation.

RESULTS

We emphasized the importance of the general tobacco control atmosphere during smoking cessation training of 139 HCPs to motivate them to engage in tobacco control advocacy. In addition to enhancing their knowledge and skills in cessation, the HCPs were then involved in the establishment of three in-hospital smoking cessation clinics and served as smoking cessation counselors since June 2008. Moreover, they ventured outside the clinics and the community to publicize smoking cessation. Their effort has contributed to smoke-free legislation, better surveillance on smoking and media advocacy on tobacco control in China.

CONCLUSIONS

The training and establishment of smoking cessation clinics could serve as a means to motivate and empower HCPs who could contribute to broaden tobacco control policy in China.

Nur77 promotes cigarette smoke‑induced autophagic cell death by increasing the dissociation of Bcl2 from Beclin-1

Chronic obstructive pulmonary disease (COPD) is characterized by partially reversible airflow limitation and persistent alveolar destruction, and autophagy is involved in the pathogenesis of cigarette smoke (CS)‑induced COPD. Nuclear receptor 77 (Nur77) participates in a number of biological processes, including apoptosis, autophagy and in disease pathogenesis; however, the role of Nur77 in COPD remains unknown. Thus, in this study, we aimed to elucidate the role of Nur77 in COPD. We report that CS promotes Nur77 expression and nuclear export in vivo and in vitro, which increases cigarette smoke extract (CSE)‑induced autophagy. In addition, we found that lung tissues, human bronchial epithelial (HBE) cells and A549 cells exposed to CS or CSE expressed lower levels of LC3 and Beclin‑1 and contained fewer autophagosomes following Nur77 knockdown with siRNA‑Nur77. Moreover, a co‑immunoprecipitation assay demonstrated that CSE promoted autophagy, partly by accelerating the interaction between Nur77 and Bcl2, in turn leading to the increased dissociation of Bcl2 from Beclin‑1; by contrast, leptomycin B (LMB) suppressed the dissociation of Bcl2 from Beclin‑1. Taken together, the findings of this study demonstrate that Nur77 is involved in the CSE‑induced autophagic death of lung cells, and that this process is partially dependent on the increased interaction between Nur77 and Bcl2, and on the dissociation of Bcl2 from Beclin‑1. This study illustrates the role of Nur77 in bronchial and alveolar destruction following exposure to CS.

The Effects of Dietary Supplements on Asthma and Lung Cancer Risk in Smokers and Non-Smokers: A Review of the Literature

Smoking is one of the major global causes of death. Cigarette smoke and secondhand (passive) smoke have been causally related to asthma and lung cancer. Asthma is a potential risk factor for developing lung cancer in both smokers and non-smokers. Prospective studies and randomized control trials (RCTs) of dietary supplements and lung cancer risk in adult smokers and non-smokers have yielded inconsistent results. A few prospective studies have shown that long-term use of high doses of some supplements, such as retinol, β-carotene, B vitamins, and vitamin E, increase lung cancer risk in current and former smokers. Limited evidence from RCTs suggests that vitamin D supplementation is effective in improving lung function and reducing asthma risk in current/former smokers. The relationship between dietary supplements and lung cancer risk has never before been examined in asthmatic smokers and non-smokers. This short review aims to examine the evidence from existing studies for the effects of dietary supplements on asthma/lung cancer risk and mortality in smokers and non-smokers.

Lung volumes identify an at-risk group in persons with prolonged secondhand tobacco smoke exposure but without overt airflow obstruction

Introduction

Exposure to secondhand smoke (SHS) is associated with occult obstructive lung disease as evident by abnormal airflow indices representing small airway disease despite having preserved spirometry (normal forced expiratory volume in 1 s-to-forced vital capacity ratio, FEV₁/FVC). The significance of lung volumes that reflect air trapping in the presence of preserved spirometry is unclear.

Methods

To investigate whether lung volumes representing air trapping could determine susceptibility to respiratory morbidity in people with SHS exposure but without spirometric chronic obstructive pulmonary disease, we examined a cohort of 256 subjects with prolonged occupational SHS exposure and preserved spirometry. We elicited symptom prevalence by structured questionnaires, examined functional capacity (maximum oxygen uptake, VO_2max) by exercise testing, and estimated associations of those outcomes with air trapping (plethysmography-measured residual volume-to-total lung capacity ratio, RV/TLC), and progressive air trapping with exertion (increase in fraction of tidal breathing that is flow limited on expiration during exercise (per cent of expiratory flow limitation, %EFL)).

Results

RV/TLC was within the predicted normal limits, but was highly variable spanning 22%±13% and 16%±8% across the increments of FEV₁/FVC and FEV₁, respectively. Respiratory complaints were prevalent (50.4%) with the most common symptom being ≥2 episodes of cough per year (44.5%). Higher RV/TLC was associated with higher OR of reporting respiratory symptoms (n=256; r²=0.03; p=0.011) and lower VO_2max (n=179; r²=0.47; p=0.013), and %EFL was negatively associated with VO_2max (n=32; r²=0.40; p=0.017).

Conclusions

In those at risk for obstruction due to SHS exposure but with preserved spirometry, higher RV/TLC identifies a subgroup with increased respiratory symptoms and lower exercise capacity.

Epidemiological evidence relating environmental smoke to COPD in lifelong non-smokers: a systematic review

Background: Some evidence suggests environmental tobacco smoke (ETS) might cause chronic obstructive pulmonary disease (COPD). We reviewed available epidemiological data in never smokers. Methods: We identified epidemiological studies providing estimates of relative risk (RR) with 95% confidence interval (CI) for various ETS exposure indices. Confounder-adjusted RRs for COPD were extracted, or derived using standard methods. Meta-analyses were conducted for each exposure index, with tests for heterogeneity and publication bias. For the main index (spouse ever smoked or nearest equivalent), analyses investigated variation in RR by location, publication period, study type, sex, diagnosis, study size, confounder adjustment, never smoker definition, and exposure index definition. Results: Twenty-eight relevant studies were identified; nine European or Middle Eastern, nine Asian, eight American and two from multiple countries. Five were prospective, seven case-control and 16 cross-sectional. The COPD definition involved death or hospitalisation in seven studies, GOLD stage 1+ criteria in twelve, and other definitions in nine. For the main index, random-effects meta-analysis of 33 heterogeneous (p<0.001) estimates gave a RR of 1.20 (95%CI 1.08-1.34). Higher estimates for females (1.59,1.16-2.19, n=11) than males (1.29,0.94-1.76, n=7) or sexes combined (1.10,0.99-1.22, n=15 where sex-specific not available), and lower estimates for studies of 150+ cases (1.08,0.97-1.20, n=13) partly explained the heterogeneity. Estimates were higher for Asian studies (1.34,1.08-1.67, n=10), case-control studies (1.55,1.04-2.32, n=8), and COPD mortality or hospitalisation (1.40,1.12-1.74, n=11). Some increase was seen for severer COPD (1.29,1.10-1.52, n=7). Dose-response evidence was heterogeneous. Evidence for childhood (0.88,0.72-1.07, n=2) and workplace (1.12,0.77-1.64, n=4) exposure was limited, but an increase was seen for overall adulthood exposure (1.20,1.03-1.39, n=17). We discuss study weaknesses that may bias estimation of the association of COPD with ETS. Conclusions: Although the evidence suggests ETS increases COPD, study weaknesses and absence of well-designed large studies precludes reliable inference of causality. More definitive evidence is required.

Epidemiological evidence relating environmental smoke to COPD in lifelong non-smokers: a systematic review

Background: Some evidence suggests environmental tobacco smoke (ETS) might cause chronic obstructive pulmonary disease (COPD). We reviewed available epidemiological data in never smokers. Methods: We identified epidemiological studies providing estimates of relative risk (RR) with 95% confidence interval (CI) for various ETS exposure indices. Confounder-adjusted RRs for COPD were extracted, or derived using standard methods. Meta-analyses were conducted for each exposure index, with tests for heterogeneity and publication bias. For the main index (spouse ever smoked or nearest equivalent), analyses investigated variation in RR by location, publication period, study type, sex, diagnosis, study size, confounder adjustment, never smoker definition, and exposure index definition. Results: Twenty-eight relevant studies were identified; nine European or Middle Eastern, nine Asian, eight American and two from multiple countries. Five were prospective, seven case-control and 16 cross-sectional. The COPD definition involved death or hospitalisation in seven studies, GOLD stage 1+ criteria in twelve, and other definitions in nine. For the main index, random-effects meta-analysis of 33 heterogeneous (p<0.001) estimates gave a RR of 1.20 (95%CI 1.08-1.34). Higher estimates for females (1.59,1.16-2.19, n=11) than males (1.29,0.94-1.76, n=7) or sexes combined (1.10,0.99-1.22, n=15 where sex-specific not available), and lower estimates for studies of 150+ cases (1.08,0.97-1.20, n=13) partly explained the heterogeneity. Estimates were higher for Asian studies (1.34,1.08-1.67, n=10), case-control studies (1.55,1.04-2.32, n=8), and COPD mortality or hospitalisation (1.40,1.12-1.74, n=11). Some increase was seen for severer COPD (1.29,1.10-1.52, n=7). Dose-response evidence was heterogeneous. Evidence for childhood (0.88,0.72-1.07, n=2) and workplace (1.12,0.77-1.64, n=4) exposure was limited, but an increase was seen for overall adulthood exposure (1.20,1.03-1.39, n=17). We discuss study weaknesses that may bias estimation of the association of COPD with ETS. Conclusions: Although the evidence suggests ETS increases COPD, study weaknesses and absence of well-designed large studies precludes reliable inference of causality. More definitive evidence is required.

Prevalence of active and passive tobacco smoking among Beijing residents in 2011

Objectives

This study was aimed to investigate the prevalence of active and passive tobacco smoking among Beijing residents in 2011.

Methods

A cross-sectional survey was conducted, using a stratified multistage cluster random sampling method to select a representative sample of 20,242, among Beijing residents aged 18–79 years. Active and passive tobacco smoking information was collected by a standardized and validated questionnaire in a face-to-face interview. All estimates of prevalence and numbers were weighted by the 2010 Beijing Population Census data and the sampling scheme.

Results

Among Beijing residents aged 18–79 years, the overall prevalence of ever smokers and current smokers were 33.13% and 30.18%, respectively. The prevalence in males was much higher than that in females (60.75% vs. 3.75% for ever smokers, and 55.53% vs. 3.21% for current smokers, respectively). For overall current smokers, 14.12 cigarettes were consumed per day. However, only 8.91% of ever smokers quitted smoking at the time of the survey, and 2.44% of ever smokers quitted smoking in recent two years. Furthermore, 44.74% of overall nonsmokers and former smokers, with 47.03% of males and 43.63% of females, reported exposure to secondhand smoke for at least 15 minutes per day and at least one day per week.

Conclusions

Tobacco smoking prevalence is still extremely high in Beijing. Nonsmokers do still suffer from secondhand smoke critically. Further urgent efforts for tobacco control are warranted in Beijing.

Secondhand Smoke-Prevalent Polycyclic Aromatic Hydrocarbon Binary Mixture-Induced Specific Mitogenic and Pro-inflammatory Cell Signaling Events in Lung Epithelial Cells

Low molecular weight polycyclic aromatic hydrocarbons (LMW PAHs; < 206.3 g/mol) are prevalent and ubiquitous environmental contaminants, presenting a human health concern, and have not been as thoroughly studied as the high MW PAHs. LMW PAHs exert their pulmonary effects, in part, through P38-dependent and -independent mechanisms involving cell-cell communication and the production of pro-inflammatory mediators known to contribute to lung disease. Specifically, we determined the effects of two representative LMW PAHs, 1-methylanthracene (1-MeA) and fluoranthene (Flthn), individually and as a binary PAH mixture on the dysregulation of gap junctional intercellular communication (GJIC) and connexin 43 (Cx43), activation of mitogen activated protein kinases (MAPK), and induction of inflammatory mediators in a mouse non-tumorigenic alveolar type II cell line (C10). Both 1-MeA, Flthn, and the binary PAH mixture of 1-MeA and Flthn dysregulated GJIC in a dose and time-dependent manner, reduced Cx43 protein, and activated the following MAPKs: P38, ERK1/2, and JNK. Inhibition of P38 MAPK prevented PAH-induced dysregulation of GJIC, whereas inhibiting ERK and JNK did not prevent these PAHs from dysregulating GJIC indicating a P38-dependent mechanism. A toxicogenomic approach revealed significant P38-dependent and -independent pathways involved in inflammation, steroid synthesis, metabolism, and oxidative responses. Genes in these pathways were significantly altered by the binary PAH mixture when compared with 1-MeA and Flthn alone suggesting interactive effects. Exposure to the binary PAH mixture induced the production and release of cytokines and metalloproteinases from the C10 cells. Our findings with a binary mixture of PAHs suggest that combinations of LMW PAHs may elicit synergistic or additive inflammatory responses which warrant further investigation and confirmation.

Passive smoking and chronic obstructive pulmonary disease mortality: findings from the Japan collaborative cohort study

OBJECTIVES

To elucidate the association between passive smoking at home and chronic obstructive pulmonary disease (COPD) mortality via a large-scale nationwide cohort study in Japan.

METHODS

Never smokers (n = 34,604) aged 40-79 years at baseline (1988-1990; 4884 men, 29,720 women) were included in the analysis. Passive smoking at home was measured based on self-reported frequency of weekly exposure to passive smoking at home. An inverse probability of treatment-weighted competing risk model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for COPD mortality.

RESULTS

During a median follow-up of 16.4 years, 33 participants (10 men, 23 women) died of COPD. The HR for participants exposed to passive smoking at home ≤4 days per week or those who had almost daily exposure to passive smoking at home had a significantly increased risk of COPD mortality (HR 2.40, 95% CI 1.39-4.15, HR 2.88, 95% CI 1.68-4.93, respectively).

CONCLUSIONS

The present findings suggest that avoiding passive smoking at home may be beneficial for preventing death due to COPD among never smokers.

Environmental Tobacco Smoke Exposure and Risk of Stroke in Never Smokers: An Updated Review with Meta-Analysis

OBJECTIVES

The study aimed to review the epidemiological evidence relating environmental tobacco smoke exposure to stroke in never smokers.

METHODS

The study is similar to our review in 2006, with searches extended to March 2016.

RESULTS

Twelve further studies were identified. A total of 28 studies varied considerably in design, exposure indices used, and disease definition. Based on 39 sex-specific estimates and the exposure index current spousal exposure (or nearest equivalent), the meta-analysis gave an overall fixed-effect relative risk estimate of 1.23 (95% confidence interval: 1.16-1.31), with significant (P < .05) heterogeneity. There was no significant heterogeneity by sex, continent, fatality, disease end point, or degree of adjustment for potential confounding factors. Relative risks were less elevated in prospective studies (1.15, 1.06-1.24) than in case-control studies (1.44, 1.22-1.60) or cross-sectional studies (1.40, 1.21-1.61). They also varied by publication year, but with no trend. A significant increase was not seen in studies that excluded smokers of any tobacco (1.07, .97-1.17), but was seen for studies that included pipe- or cigar-only smokers, occasional smokers, or long-term former smokers. No elevation was seen for hemorrhagic stroke. Relative risk estimates were similar using ever rather than current exposure, or total rather than spousal exposure. Eleven studies provided dose-response estimates, the combined relative risk for the highest exposure level being 1.56 (1.37-1.79). Many studies have evident weaknesses, recall bias, and particularly publication bias being major concerns.

CONCLUSIONS

Although other reviewers inferred a causal relationship, we consider the evidence does not conclusively demonstrate this. We repeat our call for publication of data from existing large prospective studies.

Association between exposure to ambient particulate matter and chronic obstructive pulmonary disease: results from a cross-sectional study in China

Objective

The association between exposure to ambient particles with a median aerodynamic diameter less than 10/2.5 µm (particulate matter, PM₁₀/_2.5) and COPD remains unclear. Our study objective was to examine the association between ambient PM₁₀/_2.5 concentrations and lung functions in adults.

Methods

A cross-sectional study was conducted in southern China. Seven clusters were randomly selected from four cities across Guangdong province. Residents aged ≥20 years in the participating clusters were randomly recruited; all eligible participants were examined with a standardised questionnaire and spirometry. COPD was defined as a post-bronchodilator FEV₁/FVC less than 70%. Atmosphere PM sampling was conducted across the clusters along with our survey.

Results

Of the subjects initially recruited, 84.4% (n=5993) were included for analysis. COPD prevalence and atmosphere PM concentration varied significantly among the seven clusters. COPD prevalence was significantly associated with elevated PM concentration levels: adjusted OR 2.416 (95% CI 1.417 to 4.118) for >35 and ≤75 µg/m³ and 2.530 (1.280 to 5.001) for >75 µg/m³ compared with the level of ≤35 µg/m³ for PM_2.5; adjusted OR 2.442 (95% CI 1.449 to 4.117) for >50 and ≤150 µg/m³ compared with the level of ≤50 µg/m³ for PM₁. A 10 µg/m³ increase in PM_2.5 concentrations was associated with a 26 mL (95% CI −43 to −9) decrease in FEV₁, a 28 mL (−49 to −8) decrease in FVC and a 0.09% decrease (−0.170 to −0.010) in FEV₁/FVC ratio. The associations of COPD with PM₁₀ were consistent with PM_2.5 but slightly weaker.

Conclusions

Exposure to higher PM concentrations was strongly associated with increased COPD prevalence and declined respiratory function.

Trial registration number

ChiCTR-OO-14004264; Post-results.

Improving the Management of COPD in Women

COPD is a highly debilitating disease that represents a substantial and growing health burden in women. There is increasing evidence for sex-related differences in COPD risk, progression, and outcomes. However, the disease receives scant attention as a women's health issue. Thus, a multifaceted approach is required to address COPD in women, including greater awareness, minimization of risk, and further elucidation of the sex-specific factors (biological and cultural) that affect risk, disease progression, and treatment success. This article reviews the current literature on the topic and provides suggestions for achieving better outcomes for the millions of women with COPD worldwide.

Epidemiological evidence on environmental tobacco smoke and cancers other than lung or breast

We reviewed 87 epidemiological studies relating environmental tobacco smoke (ETS) exposure to risk of cancer other than lung or breast in never smoking adults. This updates a 2002 review which also considered breast cancer. Meta-analysis showed no significant relationship with ETS for nasopharynx cancer, head and neck cancer, various digestive cancers (stomach, rectum, colorectal, liver, pancreas), or cancers of endometrium, ovary, bladder and brain. For some cancers (including oesophagus, colon, gall bladder and lymphoma) more limited data did not suggest a relationship. An increased cervix cancer risk (RR 1.58, 95%CI 1.29-1.93, n = 17 independent estimates), reducing to 1.29 (95%CI 1.01-1.65) after restriction to five estimates adjusting for HPV infection or sexual activity suggests a causal relationship, as do associations with nasosinus cancer observed in 2002 (no new studies since), and less so kidney cancer (RR 1.33, 95%CI 1.04-1.70, n = 6). A weaker association with total cancer (RR 1.13, 95%CI 1.03-1.35, n = 19) based on heterogeneous data is inconclusive. Inadequate confounder control, recall bias, publication bias, and occasional reports of implausibly large RRs in individual studies contribute to our conclusion that the epidemiological evidence does not convincingly demonstrate that ETS exposure causes any of the cancers studied.

Meta-analysis of the association between second-hand smoke exposure and ischaemic heart diseases, COPD and stroke

Background

Second-hand smoke (SHS) is the most important contaminant of indoor air in first world countries. The risks associated with SHS exposure are highly relevant, because many people are regularly, and usually involuntarily, exposed to SHS. This study aims to quantify the effects of SHS exposure. Therefore, its impact on ischaemic heart diseases (IHD), chronic obstructive pulmonary diseases (COPD) and stroke will be considered.

Methods

A systematic literature review was conducted to identify articles dealing with the association between SHS and the three outcomes IHD, COPD and stroke. Overall, 24 articles were included in a meta-analysis using a random effects model. Effect sizes stratified for sex and for both sexes combined were calculated.

Results

The synthesis of primary studies revealed significant effect sizes for the association between SHS exposure and all three outcomes. The highest RR for both sexes combined was found for COPD (RR = 1.66, 95 % CI: 1.38–2.00). The RR for both sexes combined was 1.35 (95 % CI: 1.22–1.50) for stroke and 1.27 (95 % CI: 1.10–1.48) for IHD. The risks were higher in women than in men for all three outcomes.

Conclusions

This is the first study to calculate effect sizes for the association between SHS exposure and the disease outcomes IHD, COPD, and stroke at once. Overall, the effect sizes are comparable with previous findings in meta-analyses and therefore assumed to be reliable. The results indicate the high relevance of public health campaigns and legislation to protect non-smokers from the adverse health effects attributable to SHS exposure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2489-4) contains supplementary material, which is available to authorized users.

Secondhand Smoke Exposure and Stroke: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study

INTRODUCTION

Stroke is a major public health concern worldwide given the associated morbidity and mortality. Smoking is a risk factor for stroke, but the relationship between secondhand smoke (SHS) exposure and stroke has been inconsistent to date. The aim of the current study was to examine the association of SHS exposure and risk of stroke and its subtypes (ischemic and hemorrhagic stroke) among nonsmokers.

METHODS

Demographic and clinical characteristics were compared by SHS exposure status for African American and white nonsmokers aged ≥45 years in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study in 2014. Hazard ratios (HRs) and corresponding 95% CIs were calculated by Cox proportional hazards models to assess the relationship between SHS exposure and stroke risk.

RESULTS

Of the 21,743 participants (38% African American, 45% male), SHS exposure in the past year was reported by 23%. Compared with those without SHS exposure, exposed participants were more likely to be female, white, younger, and reside with a smoker (all p<0.001). A total of 428 incident strokes were observed from April 2003 to March 2012 during a mean follow-up of 5.6 years. The risk of overall stroke was increased 30% among those with SHS exposure after adjustment for other stroke risk factors (95% CI=2%, 67%). This relationship appeared to be driven by ischemic strokes.

CONCLUSIONS

SHS exposure is independently associated with an increased risk of stroke. Future studies are needed to confirm these findings and examine the role of long-term effects of SHS exposure on stroke outcomes.

Risk of all-cause mortality and cardiovascular disease associated with secondhand smoke exposure: a systematic review and meta-analysis

BACKGROUND

Emerging studies have assessed the association between secondhand smoke (SHS) exposure and cardiovascular disease (CVD) as well as all-cause mortality. However, findings were not consistent due to the heterogeneity of study characteristics.

METHODS

PubMed and Embase were searched through May 2014 for prospective cohort and case-control studies investigating the associations of SHS exposure in never smokers with all-cause mortality and the risk of CVD. The main analysis was performed in studies using self-reported SHS exposure and secondary analysis was performed in studies using objectively measured SHS exposure. Summary estimates were calculated using random-effects models.

RESULTS

Twenty-three prospective and 17 case-control studies were included. The pooled relative risks (RR) for never smokers exposed to SHS in comparison with those unexposed were 1.18 [95% confidence interval (CI): 1.10-1.27] for all-cause mortality (12 studies), and 1.23 (1.16-1.31) for CVD (38 studies). The association of SHS exposure with CVD was markedly stronger among studies conducted in China (RR=1.65, 95% CI 1.27-2.13) than that in the US (RR=1.09, 95% CI 1.03-1.16). Studies using objectively measured SHS exposure demonstrated a slightly higher risk for CVD compared with those using self-reported SHS exposure.

CONCLUSIONS

Exposure to SHS significantly increased the risk for all-cause mortality and CVD. The risk associated with SHS exposure was large in China while the risk was only modest in the US. Studies using objectively measured SHS exposure may yield a higher risk of CVD than those using self-reported SHS exposure.

Changes in and patterns of smoking exposure in an elderly urban population in Beijing: 2001-2010

OBJECTIVE

The study aims to explore the patterns and changes of active and passive smoking in the elderly population.

METHODS

Two cross-sectional surveys with representative samples of urban populations, aged between 60 and 95 years old, were conducted in 2001 and 2010 in Beijing. A current smoker was defined as a person who smoked a tobacco product at the time of the survey, and a passive smoker was defined as a person who had been exposed to smoke exhaled by a smoker for more than 15 minutes per day more than once per week.

RESULTS

A total of 2,277 participants in 2001 and 2,102 participants in 2010 completed the survey. The current smoking prevalence changed slightly in males (24.7 vs. 21.2%, P = 0.081), while the prevalence in females decreased significantly from 8.8% (95% CI: 7.3-10.3%) in 2001 to 4.1% (95% CI: 3.0-5.2%) in 2010 (P<0.001). The prevalence of passive smoking was 30.5% (95% CI: 28.6-32.4%) in 2001 and 30.0% (95% CI: 28.1-32.0%) in 2010. The main source of secondhand smoke switched from a spouse in 2001 to offspring in 2010. This trend was observed in both sexes. Passive smoking in males from a smoking spouse decreased from 5.7% to 2.4% (P<0.001), while that from smoking offspring increased from 7.3 to 14.5% (P<0.001). Passive smoking in females from a spouse decreased from 30.6 to 17.6%, while that from offspring increased from 5.3 to 15.4% (P<0.001).

CONCLUSION

Offspring became the main source of secondhand smoke for the elderly. Our findings demonstrated the importance of implementing smoking prevention programs, to educate older adults who live with a smoking spouse and/or offspring.

Socioeconomic differentials in the immediate mortality effects of the national Irish smoking ban

BACKGROUND

Consistent evidence has demonstrated that smoking ban policies save lives, but impacts on health inequalities are uncertain as few studies have assessed post-ban effects by socioeconomic status (SES) and findings have been inconsistent. The aim of this study was to assess the effects of the national Irish smoking ban on ischemic heart disease (IHD), stroke, and chronic obstructive pulmonary disease (COPD) mortality by discrete and composite SES indicators to determine impacts on inequalities.

METHODS

Census data were used to assign frequencies of structural and material SES indicators to 34 local authorities across Ireland with a 2000-2010 study period. Discrete indicators were jointly analysed through principal component analysis to generate a composite index, with sensitivity analyses conducted by varying the included indicators. Poisson regression with interrupted time-series analysis was conducted to examine monthly age and gender-standardised mortality rates in the Irish population, ages ≥35 years, stratified by tertiles of SES indicators. All models were adjusted for time trend, season, influenza, and smoking prevalence.

RESULTS

Post-ban mortality reductions by structural SES indicators were concentrated in the most deprived tertile for all causes of death, while reductions by material SES indicators were more equitable across SES tertiles. The composite indices mirrored the results of the discrete indicators, demonstrating that post-ban mortality decreases were either greater or similar in the most deprived when compared to the least deprived for all causes of death.

CONCLUSIONS

Overall findings indicated that the national Irish smoking ban reduced inequalities in smoking-related mortality. Due to the higher rates of smoking-related mortality in the most deprived group, even equitable reductions across SES tertiles resulted in decreases in inequalities. The choice of SES indicator was influential in the measurement of effects, underscoring that a differentiated analytical approach aided in understanding the complexities in which structural and material factors influence mortality.

Tobacco smoking, epilepsy, and seizures

Tobacco smoking is considered the greatest risk factor for death caused by noncommunicable diseases. In contrast to extensive research on the association between tobacco smoking and diseases such as heart attack, stroke, and cancers, studies on the association between tobacco smoking and seizures or epilepsy are insufficient. The exact roles tobacco smoking and nicotine use play in seizures or epilepsy have not been well reviewed. We reviewed available literature and found that 1) there are vast differences between tobacco smoke and nicotine based on their components and their effects on seizures or epilepsy; 2) the seizure risk in acute active tobacco smokers, women who smoke during pregnancy, electronic cigarette smokers, and the role of smoking in sudden unexplained/unexpected death in epilepsy remain unclear; 3) seizure risks are higher in acute secondhand smokers, chronic active smokers, and babies whose mothers smoke; 4) tobacco smoke protects against seizures in animal models whereas nicotine exerts mixed effects in animals; and 5) tobacco smoking agents can be noneffective, proconvulsant, or anticonvulsant. Finally, the opportunities for future research on this topic is discussed.

Secondhand smoke exposure and intermittent claudication: a Scotland-wide study of 4231 non-smokers

OBJECTIVE

Active smoking is an important risk factor for peripheral arterial disease. In contrast, published evidence on the association with secondhand smoke (SHS) is very limited. The aim of this study was to examine the association between SHS exposure and intermittent claudication (IC) among middle aged non-smokers.

DESIGN

Multivariate logistic regression analyses were used to adjust for potential confounders.

SETTING

The Scottish Health Survey, a pan-Scotland, representative survey of the general population.

PATIENTS

We conducted a cross-sectional study using the Scottish Health Surveys undertaken between 1998 and 2010. Inclusion was restricted to participants aged > 45 years.

MAIN OUTCOME MEASURES

Of the 4231 confirmed non-smokers (self-reported non-smokers with salivary cotinine concentrations < 15 ng/mL), 134 (3.2%) had IC based on the Edinburgh Claudication Questionnaire.

RESULTS

There was evidence of a dose relationship, whereby the risk of IC increased with increasing cotinine concentration. Following adjustment for potential confounders, participants with a cotinine concentration ≥ 2.7 ng/mL were still significantly more likely to have IC (OR 1.76, 95% CI 1.04 to 3.00; p = 0.036) compared with those with a cotinine concentration < 0.7 ng/mL. Among non-smokers, 5.6% (95% CI -0.8% to 11.7%) of cases of IC were attributable to cotinine concentrations ≥ 2.7 ng/mL and a further 3.6% (95% CI -6.6% to 12.8%) to cotinine concentrations of 0.7-2.6 ng/mL.

CONCLUSIONS

As with coronary heart disease and stroke, SHS exposure was independently associated with IC. Our findings add to the published evidence in support of protecting the general public from SHS exposure.

Polycyclic aromatic hydrocarbon-induced signaling events relevant to inflammation and tumorigenesis in lung cells are dependent on molecular structure

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental and occupational toxicants, which are a major human health concern in the U.S. and abroad. Previous research has focused on the genotoxic events caused by high molecular weight PAHs, but not on non-genotoxic events elicited by low molecular weight PAHs. We used an isomeric pair of low molecular weight PAHs, namely 1-Methylanthracene (1-MeA) and 2-Methylanthracene (2-MeA), in which only 1-MeA possessed a bay-like region, and hypothesized that 1-MeA, but not 2-MeA, would affect non-genotoxic endpoints relevant to tumor promotion in murine C10 lung cells, a non-tumorigenic type II alveolar pneumocyte and progenitor cell type of lung adenocarcinoma. The non-genotoxic endpoints assessed were dysregulation of gap junction intercellular communication function and changes in the major pulmonary connexin protein, connexin 43, using fluorescent redistribution and immunoblots, activation of mitogen activated protein kinases (MAPK) using phosphospecific MAPK antibodies for immunoblots, and induction of inflammatory genes using quantitative RT-PCR. 2-MeA had no effect on any of the endpoints, but 1-MeA dysregulated gap junctional communication in a dose and time dependent manner, reduced connexin 43 protein expression, and altered membrane localization. 1-MeA also activated ERK1/2 and p38 MAP kinases. Inflammatory genes, such as cyclooxygenase 2, and chemokine ligand 2 (macrophage chemoattractant 2), were also upregulated in response to 1-MeA only. These results indicate a possible structure-activity relationship of these low molecular weight PAHs relevant to non-genotoxic endpoints of the promoting aspects of cancer. Therefore, our novel findings may improve the ability to predict outcomes for future studies with additional toxicants and mixtures, identify novel targets for biomarkers and chemotherapeutics, and have possible implications for future risk assessment for these PAHs.

The involvement of NRF2 in lung cancer

Nuclear factor, erythroid-derived 2, like 2 (NRF2) is a key regulator of antioxidants and cellular stress responses. The role of NRF2 in pulmonary neoplasia, a diverse disease for which few biomarkers exist, is complicated and appears to depend on several main factors including the existence of activating mutations in NRF2 and/or loss of function mutations in KEAP1 and the stage of carcinogenesis studied, particularly in the mouse models tested. Therapeutic strategies for lung cancer targeting NRF2 have observed mixed results, both anti- and protumorigenic effects; however, these differences seem to reflect the mutation status of NRF2 or KEAP1. In this paper, we will discuss the studies on human NRF2 and the mechanisms proposed, several mouse models using various mice deficient in NRF2, as well as xenograft models, and the chemotherapeutic strategies using the NRF2 pathway.