Multicenter case-control study of exposure to environmental tobacco smoke and lung cancer in Europe

Evaluation of Risk Factors for Lung Cancer Among Never Smokers and Their Association With Common Driver Mutations

INTRODUCTION

The majority of lung cancers are caused by tobacco use, which is linked to lung tumors of all major histological types. A considerable fraction of lung cancer cases, the vast majority of which are adenocarcinomas, occur in "never smokers," who are characterized as having smoked fewer than 100 cigarettes in their lives. The primary objective was to assess risk factors for lung cancer in non-smokers. In contrast, secondary objectives included evaluating histological subtype, staging, and performance status and exploring associations between risk factors and common driver mutations.

MATERIAL AND METHODS

The study was a single-center, observational, case-control study done at All India Institute of Medical Science, Bhubaneswar, India that focused on non-smokers with lung cancer. It included 145 cases and 297 controls, with statistical analyses such as chi-square tests and logistic regression used to assess associations between risk factors and lung cancer, considering factors such as socioeconomic status, body mass index (BMI), occupation, outdoor and indoor air pollution, personal habits, and medical history.

RESULTS

The study, comprising 145 lung cancer cases in non-smokers and 297 controls, found that 92.4% (134/145) of cases had adenocarcinoma, 6.9% (10/145) had squamous cell carcinoma, and 0.7% (1/145) had small cell carcinoma. Significant associations were observed for high-risk occupations, indoor biomass use without proper ventilation, low BMI, and family history of lung cancer. Specific pre-existing lung conditions like old pulmonary tuberculosis and asthma were linked to increased and decreased odds of developing lung cancer, respectively. Environmental factors, living near heavy industry, and dietary habits showed significant associations. A significant association was not found between the driver mutations and the risk factors studied.

CONCLUSION

This single-center study sheds light on significant risk factors influencing lung cancer development among non-smokers. The predominant occurrence of adenocarcinoma and associations with high-risk occupations, indoor biomass exposure, low BMI, and family history emphasize the multifaceted nature of non-smoking-related lung cancer. The findings underscore the importance of comprehensive risk assessment and targeted preventive strategies in this population.

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.

Phytoestrogens and lung cancer risk: a nested case-control study in never-smoking Chinese women

BACKGROUND

Since several lines of evidence suggest that estrogens may be involved in lung carcinogenesis, it has been hypothesized that intake of phytoestrogens, similar in molecular structure to mammalian estrogens, may be associated with lung cancer development.

OBJECTIVE

The aim was to prospectively evaluate the association between phytoestrogen exposure and lung cancer risk in never-smoking women.

METHODS

We conducted a nested case-control study within a population-based prospective cohort study of women. A total of 478 incident lung cancer cases and their individually matched controls were identified among never-smoking women after a mean follow-up of 15.6 years. Habitual intake of and internal exposure to phytoestrogens were assessed by repeated dietary surveys and urinary biomarkers, respectively. ORs and 95% CIs for lung cancer were estimated in conditional logistic regression models.

RESULTS

After adjustment for potential confounders, a moderate intake of dietary isoflavones was inversely associated with lung cancer risk in never-smoking women, with the OR for the second quartile vs. the lowest quartile of intake being 0.52 (95% CI: 0.35, 0.76). Further increasing intake did not convey additional benefits, with ORs (95% CI) for the third and fourth quartiles of 0.53 (0.36, 0.78) and 0.47 (0.31, 0.72), respectively (P-overall < 0.001 and P-nonlinearity = 0.006). A similar association was seen when exposure to isoflavones was assessed by urinary biomarkers. ORs (95% CI) for the second, third, and fourth quartiles compared with the lowest quartile of urinary isoflavone excretion were 0.57 (0.39, 0.83), 0.64 (0.44, 0.92), and 0.60 (0.41, 0.86), respectively. The inverse association reached a plateau beyond the second quartile, with P-overall = 0.04 and P-nonlinearity = 0.15. Urinary excretion of gut-microbiota-derived metabolites of lignans was not related to lung cancer risk.

CONCLUSIONS

This study suggests that moderately increasing intake of isoflavone-rich foods is associated with lower risk of lung cancer in never-smoking women.

Risk of lung cancer among women in relation to lifetime history of tobacco smoking: a population-based case-control study in France (the WELCA study)

Background

This study aims to provide new insights on the role of smoking patterns and cigarette dependence in female lung cancer, and to examine differences by histological subtype.

Methods

We conducted a population-based case-control study in the great Paris area among women including 716 incident cases diagnosed between 2014 and 2017 and 757 age-matched controls. Detailed data on smoking history was collected during in-person interviews to assess intensity and duration of tobacco smoking, time since cessation, smoking habits (depth of smoke inhalation, use of filter, type of tobacco, and type of cigarettes) and Fagerström test for cigarette dependence. The comprehensive smoking index (CSI), a score modelling the combined effects of intensity, duration and time since quitting smoking was determined for each subject. Multivariable logistic regression models were fitted to calculate odds ratios (ORs) and their confidence intervals (95%CI) of lung cancer associated with smoking variables.

Results

Lung cancer risk increased linearly with intensity and duration of tobacco smoking while it decreased with time since cessation, to reach the risk in never-smokers after 20 years of abstinence. The combined effect of intensity and duration of tobacco smoking was more than multiplicative (p-interaction 0.012). The OR in the highest vs the lowest quartile of CSI was 12.64 (95%CI 8.50; 18.80) (p-trend < 0.001). The risk of small cell or squamous cell carcinomas increased with the CSI more sharply than the risk of adenocarcinomas. Deep smoke inhalation, dark vs blond tobacco, conventional vs light cigarettes, and unfiltered vs filtered cigarettes, as well as having mixed smoking habits, were found to be independent risk factors. Having high cigarette addiction behaviours also increased the risk after adjusting for CSI.

Conclusion

This study provides additional insights on the effects of tobacco smoking patterns on lung cancer risk among women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08433-z.

L-TRUST: Long-term risk of cancer in patients under statins therapy. A systematic review and meta-analysis

INTRODUCTION

Statins are widely prescribed drugs with established efficacy in primary and secondary prevention of cardiovascular events. Although they are mostly well tolerated, several authors have been emphasizing that the statins' safety profile is not totally clarified especially when considering risk of cancer in patients with long-term exposure to statins. This meta-analysis was aimed at evaluating the risk of cancer in patients with prolonged exposure to statins.

METHODS

Medline, Cochrane library, and clinicaltrials.gov were searched in order to identify studies with a minimum average follow-up of 10 years of exposure to statins and a cancer-related outcome reported. Relative risk (RR) of the primary outcomes and the combined effect was presented using a random-effects model. In the selected randomized control trials (RCT), statin exposure was compared with placebo, and in the selected observational studies, it was compared with no exposure to statins.

RESULTS

We retrieved 1627 studies, of which 15 full-papers were included for final review, five RCT, two cohort studies (CSs), and eight case-control studies (CCs), representing a total of 358 544 patients. Five RCT, two cohort studies (CSs), and eight case-control studies (CCs). No significant differences were found regarding risk of cancer occurrence (RR = 1.08, 0.96-1.21) or cancer mortality (RR = 0.91, 0.80-1.04) due to long-term statin exposure. Regarding all-cause mortality, a protective effect was found (RR = 0.93, 0.90-0.97).

CONCLUSIONS

According to available and published evidence, statins are not associated with an increased risk of cancer after prolonged exposure. These findings strengthen the role of statins in the primary and secondary prevention of cardiovascular events.

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.

Night shift work exposure profile and obesity: Baseline results from a Chinese night shift worker cohort

AIMS

This study aimed to evaluate the associations between types of night shift work and different indices of obesity using the baseline information from a prospective cohort study of night shift workers in China.

METHODS

A total of 3,871 workers from five companies were recruited from the baseline survey. A structured self-administered questionnaire was employed to collect the participants' demographic information, lifetime working history, and lifestyle habits. Participants were grouped into rotating, permanent and irregular night shift work groups. Anthropometric parameters were assessed by healthcare professionals. Multiple logistic regression models were used to evaluate the associations between night shift work and different indices of obesity.

RESULTS

Night shift workers had increased risk of overweight and obesity, and odds ratios (ORs) were 1.17 (95% CI, 0.97-1.41) and 1.27 (95% CI, 0.74-2.18), respectively. Abdominal obesity had a significant but marginal association with night shift work (OR = 1.20, 95% CI, 1.01-1.43). A positive gradient between the number of years of night shift work and overweight or abdominal obesity was observed. Permanent night shift work showed the highest odds of being overweight (OR = 3.94, 95% CI, 1.40-11.03) and having increased abdominal obesity (OR = 3.34, 95% CI, 1.19-9.37). Irregular night shift work was also significantly associated with overweight (OR = 1.56, 95% CI, 1.13-2.14), but its association with abdominal obesity was borderline (OR = 1.26, 95% CI, 0.94-1.69). By contrast, the association between rotating night shift work and these parameters was not significant.

CONCLUSION

Permanent and irregular night shift work were more likely to be associated with overweight or abdominal obesity than rotating night shift work. These associations need to be verified in prospective cohort studies.

'The industry must be inconspicuous': Japan Tobacco's corruption of science and health policy via the Smoking Research Foundation

OBJECTIVE

To investigate how and why Japan Tobacco, Inc. (JT) in 1986 established the Smoking Research Foundation (SRF), a research-funding institution, and to explore the extent to which SRF has influenced science and health policy in Japan.

METHODS

We analysed documents in the Truth Tobacco Industry Documents archive, along with recent Japanese litigation documents and published documents.

RESULTS

JT's effort to combat effective tobacco control was strengthened in the mid-1980s, following privatisation of the company. While remaining under the protection of Japan's Ministry of Finance, the semiprivatised company lost its 'access to politicos', opening up a perceived need for collaboration with global cigarette makers. One solution, arrived at through clandestine planning with American companies, was to establish a third-party organisation, SRF, with the hope of capturing scientific and medical authority for the industry. Guarded by powerful people in government and academia, SRF was launched with the covert goal of influencing tobacco policy both inside and outside Japan. Scholars funded by SRF have participated in international conferences, national advisory committees and tobacco litigation, in most instances helping the industry to maintain a favourable climate for the continued sale of cigarettes.

CONCLUSIONS

Contrary to industry claims, SRF was never meant to be independent or neutral. With active support from foreign cigarette manufacturers, SRF represents the expansion into Asia of the denialist campaign that began in the USA in 1953.

Epidemiology in Germany-general development and personal experience

Did you ever hear about epidemiology in Germany? Starting from an epidemiological desert the discipline has grown remarkably, especially during the last 10-15 years: research institutes have been established, research funding has improved, multiple curriculae in Epidemiology and Public Health are offered. This increase has been quite steep, and now the epidemiological infrastructure is much better. Several medium-sized and even big population cohorts are ongoing, and the number and quality of publications from German epidemiologists has reached a respectable level. My own career in epidemiology started in the field of environmental health. After German reunification I concentrated for many years on environmental problems in East Germany and observed the health benefits after improvement of the situation. Later, I concentrated on population-based cohorts in newborns (GINI/LISA) and adults (KORA, German National Cohort), and on biobanking. This Essay describes the development in Germany after worldwar 2, illustrated by examples of research results and build-up of epidemiological infractructures worth mentioning.

A critical review of the relationship between occupational exposure to diesel emissions and lung cancer risk

In 2012, a working group of the International Agency for Research on Cancer classified diesel exhaust (DE) as a human carcinogen (Group 1). This decision was primarily based on the findings of the Diesel Exhaust in Miners Study (DEMS). The disparity between the results of various methodological approaches applied to the DEMS led to several critical commentaries. An expert panel was subsequently set up by the Health Effects Institute to evaluate the DEMS results, together with a large study in the trucking industry. The panel concluded that both studies provided a useful basis for quantitative risk assessments (QRAs) of DE exposure. However, the results of both studies were non-definitive as the studies suffer from several methodological shortcomings. We conducted a critical review of the studies used by the International Agency for Research on Cancer (IARC) working group to evaluate the relationship between DE and lung cancer. The aim was to assess whether the available studies support the statement of a causal relationship and, secondarily if they could be used for QRA. Our review highlights several methodological flaws in the studies, amongst them overadjustment bias, selection bias, and confounding bias. The conclusion from our review is that the currently published studies provide little evidence for a definite causal link between DE exposure and lung cancer risk. Based on two studies in miners, the DEMS and the German Potash Miners study, QRA may be conducted. However, the DEMS data should be reanalyzed in advance to avoid bias that affects the presently published risk estimates.

"You've Come a Long Way, Baby": The Convergence in Age Patterns of Lung Cancer Mortality by Sex, United States, 1959-2013

We analyze lung cancer mortality by age and sex in the United States, 1959-2013. It is already known that male lung cancer death rates exceed those of women and that tobacco use is the leading reason for the sex difference. We elaborate on this knowledge by showing that unlike most causes of death, lung cancer mortality patterns by age are a very good fit to a quadratic-Gompertz model, i.e., log mortality rates are quadratic by age, with the mode above age 70. With a little additional historical data on sex differences in tobacco use, the quadratic models help to paint a clear quantitative picture of behavior-led convergence in lung cancer mortality by sex. The shape of the sex-specific mortality curves have converged dramatically: since 1983, the sexes have had statistically indistinguishable shapes of their quadratic-Gompertz mortality curves. Female lung cancer mortality patterns have shown a transformation from a nonsmoking to a smoking pattern. The modal age of the quadratic-Gompertzian lung cancer death rates has potential application in countries at earlier stages of the global tobacco epidemic. Where the modal age is falling (year-on-year), we can infer that the local lung cancer epidemic is getting worse, and where it is rising, that it has begun to abate.

Systematic review of health and behavioural outcomes of smoking cessation interventions in prisons

Objective

We conducted a systematic review to examine the impact of smoking cessation interventions, including smoking bans, on prisoners and prison staff.

Data sources

We systematically searched health and criminal justice databases for relevant studies. Search strings were used to combine terms related to smoking cessation interventions with terms related to incarceration. We used forward and backward snowballing to capture additional studies.

Study selection

Studies were included if: they were published between 1 January 1994 and 23 May 2016; the population was incarcerated adults and/or prison staff; they had a quantitative component; they were published in English; and they reported outcomes of a smoking cessation programme/ban with regard to reported change in smoking behaviour and/or behavioural outcomes.

Data extraction

Studies were reviewed for methodological rigour using the Effective Public Health Practice Project's Quality Assessment Tool for Quantitative Studies. Data were independently reviewed for methodological quality by 1 author and a research assistant.

Data synthesis

Cessation programmes, including free nicotine replacement therapy and/or behavioural counselling can significantly increase the likelihood of quitting in prison and increase abstinence postrelease. Indoor bans have little impact on prisoner smoking behaviour. Prisoners who experience a complete smoking ban typically resume smoking shortly after release from prison. Bans may result in adverse behavioural outcomes, but these are generally minimal and short-lived.

Conclusions

While there is limited evidence to inform tobacco control policies in custodial settings, outcomes of this review suggest that cessation programmes/bans can be an effective mechanism to interrupt prisoner smoking behaviour when properly enforced.

Secondhand smoke exposure and risk of lung cancer in Japan: a systematic review and meta-analysis of epidemiologic studies

OBJECTIVE

Systematic evaluation of the association between secondhand smoke exposure and lung cancer in Japan has yet to be conducted. Here, we performed a systematic review and meta-analysis of the relationship between secondhand smoke and lung cancer in Japanese non-smokers.

METHODS

Relevant studies were collected from the MEDLINE and Ichushi Web databases using a combination of search terms and Medical Subject Headings. Eligible studies were identified, and relative risks or odds ratios were extracted to calculate pooled risk estimates. This procedure was performed independently by at least two authors. Stratified analyses were carried out according to study design, publication year, and whether or not potential confounding variables were accounted for. The presence of publication bias was assessed via funnel plots.

RESULTS

We identified four cohort studies and five case-control studies. Quantitative synthesis was conducted only for secondhand smoke exposure in the home during adulthood. Of the 12 populations included in meta-analysis, positive secondhand smoke exposure-lung cancer associations were observed in 11, whereas an inverse association was found in the remaining 1. The pooled relative risk of lung cancer associated with secondhand smoke exposure was 1.28 (95% confidence interval: 1.10-1.48). We found no evidence of publication bias, and a significant association remained even when potentially missing studies were included (pooled relative risk: 1.26; 95% confidence interval: 1.09-1.46). The results were stable across different subgroup analyses, including by study design, publication year, and when adjusting for confounding variables.

CONCLUSIONS

Secondhand smoke exposure in the home during adulthood results in a statistically significant increase in the risk of lung cancer.

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.

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.

Demonstration program of population-based lung cancer screening in China: Rationale and study design

BACKGROUND

Lung cancer is the leading cause of cancer-related death and has become an enormous economic burden in China. Low-dose spiral computed tomography (LDCT) screening could reduce lung cancer mortality. The feasibility of conducting a population-based lung cancer screening with LDCT in China is uncertain.

METHODS

In 2010, a demonstration program of lung cancer screening was initiated in China. High-risk individuals were enrolled in a cluster sampling design in different centers. Participants received baseline and annual screening with spiral CT and follow-up information was collected. The objective of this program is to evaluate the feasibility of conducting population-based LDCT lung cancer screening in the Chinese context. The rates of detection, early diagnosis and treatment are defined as indicators of program performance. The optimal management strategies for nodules are explored in the Chinese context based on experiences in other studies overseas.

RESULTS

A demonstration program of ongoing prospective, multi-center, population-based lung cancer screening is being performed in China.

CONCLUSIONS

This demonstration program will provide opportunities to explore the feasibility of LDCT lung cancer screening in the Chinese setting.

Exposure to secondhand tobacco smoke and lung cancer by histological type: a pooled analysis of the International Lung Cancer Consortium (ILCCO)

While the association between exposure to secondhand smoke and lung cancer risk is well established, few studies with sufficient power have examined the association by histological type. In this study, we evaluated the secondhand smoke-lung cancer relationship by histological type based on pooled data from 18 case-control studies in the International Lung Cancer Consortium (ILCCO), including 2,504 cases and 7,276 control who were never smokers and 10,184 cases and 7,176 controls who were ever smokers. We used multivariable logistic regression, adjusting for age, sex, race/ethnicity, smoking status, pack-years of smoking, and study. Among never smokers, the odds ratios (OR) comparing those ever exposed to secondhand smoke with those never exposed were 1.31 (95% CI: 1.17-1.45) for all histological types combined, 1.26 (95% CI: 1.10-1.44) for adenocarcinoma, 1.41 (95% CI: 0.99-1.99) for squamous cell carcinoma, 1.48 (95% CI: 0.89-2.45) for large cell lung cancer, and 3.09 (95% CI: 1.62-5.89) for small cell lung cancer. The estimated association with secondhand smoke exposure was greater for small cell lung cancer than for nonsmall cell lung cancers (OR=2.11, 95% CI: 1.11-4.04). This analysis is the largest to date investigating the relation between exposure to secondhand smoke and lung cancer. Our study provides more precise estimates of the impact of secondhand smoke on the major histological types of lung cancer, indicates the association with secondhand smoke is stronger for small cell lung cancer than for the other histological types, and suggests the importance of intervention against exposure to secondhand smoke in lung cancer prevention.

Exposure to environmental tobacco smoke (ETS) and risk of lung cancer in Montreal: a case-control study

BACKGROUND

The objective of the present study was to examine the association between environmental tobacco smoke (ETS) and risk of lung cancer among never smokers, defined as subjects who smoked less than 100 cigarettes in their lifetime.

METHODS

We conducted a population-based case-control study on lung cancer in Montreal, Canada (1996-2000) including 1,203 cases and 1513 controls. The present analysis is restricted to the 44 cases and 436 population controls who reported never smoking and completed the questionnaire on lifetime ETS exposure. Collected information included duration and intensity of exposure from multiple sources: inside home (parents, spouses, roommates and any other co-resident) and outside homes (in vehicles, social settings, and workplace). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated between ETS and lung cancer, adjusting for age, sex, socioeconomic status (SES), and proxy respondent.

RESULTS

Overall there was no association between ETS cumulative exposure from all sources (measured in pack-years) and lung cancer: OR = 0.98 (95%CI: 0.40-2.38), comparing upper with lower tertiles of exposure. While there were no elevated ORs associated with ever having lived with parents who smoked (OR = 0.62; 95%CI: 0.32-1.21) or with spouses who smoked (OR = 0.39; 95%CI: 0.18-0.85), ETS exposure from sources outside homes was associated with a slight, although non-significant increased risk: OR = 2.30 (95%CI: 0.85-6.19) for the upper 50% exposed. There were no clear differences in ORs by age at exposure to ETS or by histologic type of tumour, though numbers of subjects in subgroup analyses were too small to provide reliable estimates.

CONCLUSION

No clear association between lifetime ETS exposure from all sources and increased risk of lung cancer was found in the current study.

[A cohort study on risk factors of lung cancer in Yunnan tin miners]

背景与目的

吸烟是肺癌的主要病因, 在矿工肺癌病因的研究中发现, 职业暴露因素也起重要作用。本研究旨在分析氡暴露、吸烟等危险因素对云锡矿工肺癌的影响, 为预防和控制肺癌高发提供科学依据。

方法

利用前瞻性队列研究方法, 对云锡矿工肺癌高危人群暴露因素对肺癌死亡的影响进行Cox多因素分析; 分析矿工肺癌危险与初始氡暴露年龄及氡暴露率的关系, 分析不同吸烟、氡暴露水平下肺癌死亡的危险, 并对吸烟和累积氡暴露量之间的交互作用进行分析。

结果

进入研究时的年龄、吸烟量、累积氡砷暴露、既往慢性支气管炎为云锡矿工肺癌的独立危险因素, 教育程度是矿工肺癌的保护性因素; 肺癌危险与氡暴露率间存在逆剂量率效应, 但与初始氡暴露年龄无明显关联; 吸烟和氡暴露对肺癌危险有显著的相加交互作用。

结论

云锡矿工肺癌高死亡率是多种因素共同作用的结果, 危险因素间的交互作用值得进一步深入研究。

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.

Burden of household environmental tobacco smoke on medical expenditure for Japanese women: a population-based cohort study

BACKGROUND

The economic consequences of environmental tobacco smoke (ETS) have been simulated using models. We examined the individual-level association between ETS exposure and medical costs among Japanese nonsmoking women.

METHODS

This population-based cohort study enrolled women aged 40 to 79 years living in a rural community. ETS exposure in homes at baseline was assessed with a self-administered questionnaire. We then collected health insurance claims data on direct medical expenditures from 1995 through 2007. Using generalized linear models with interaction between ETS exposure level and age stratum, average total monthly expenditure (inpatient plus outpatient care) per capita for nonsmoking women highly exposed and moderately exposed to ETS were compared with expenditures for unexposed women. We performed separate analyses for survivors and nonsurvivors.

RESULTS

We analyzed data from 4870 women. After adjustment for potential confounding factors, survivors aged 70 to 79 who were highly exposed to ETS incurred higher expenditures than those who were not exposed. We found no significant difference in expenditures between moderately exposed and unexposed women. Total expenditures were not significantly associated with ETS exposure among survivors aged 40 to 69 or nonsurvivors of any age stratum.

CONCLUSIONS

We calculated individual-level excess medical expenditures attributable to household exposure to ETS among surviving older women. The findings provide direct evidence of the economic burden of ETS, which is helpful for policymakers who seek to achieve the economically attractive goal of eliminating ETS.

Implementation and impact of anti-smoking interventions in three prisons in the absence of appropriate legislation

OBJECTIVE

To assess the acceptability and impact of anti-smoking policies in three prisons in Switzerland.

METHODS

A before-after intervention study in A) an open prison for sentenced prisoners, B) a closed prison for sentenced prisoners, and C) a prison for pretrial detainees. Prisoners and staff were surveyed before (2009, n=417) and after (2010-2011, n=228) the interventions. Medical staff were trained to address tobacco dependence systematically in prisoners. In prison A, a partial smoking ban was extended. No additional protection against second-hand smoke was feasible in prisons B and C.

RESULTS

In prison A, more prisoners reported receiving medical help to quit smoking in 2011 (20%) than in 2009 (4%, p=0.012). In prison A, prisoners and staff reported less exposure to second-hand smoke in 2011 than in 2009: 31% of prisoners were exposed to smoke at workplaces in 2009 vs 8% in 2011 (p=0.001); in common rooms: 43% vs 8%, (p<0.001). No changes were observed in prisons B and C.

CONCLUSIONS

Reinforcement of non-smoking rules was possible in only one of the three prisons but had an impact on exposure to tobacco smoke and medical help to quit. Implementing anti-smoking policies in prisons is difficult in the absence of appropriate legislation.

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.

Similar DNA methylation pattern in lung tumours from smokers and never-smokers with second-hand tobacco smoke exposure

Tobacco smoke causes lung cancer in smokers and in never-smokers exposed to second-hand tobacco smoke (SHS). Nonetheless, molecular mechanisms of lung cancer in SHS-exposed never-smokers are still elusive. We studied lung cancers from current smokers (n = 109), former smokers (n = 56) and never-smokers (n = 47) for promoter hypermethylation of five tumour suppressor genes--p16, RARB, RASSF1, MGMT and DAPK1--using methylation-specific polymerase chain reaction. Lung tumours from ever-smokers suggested an increased risk of p16 hypermethylation as compared to never-smokers (P = 0.073), with former smokers having the highest frequency of p16 hypermethylation (P = 0.044 versus current smokers and P = 0.009 versus never-smokers). In the never-smoking group, p16 hypermethylation was seen in lung tumours from SHS-exposed individuals (4/33; 12%) but in none of the non-exposed individuals (0/9). The overall occurrence of hypermethylation (measured both as methylation index and as number of genes affected) was similar in those ever exposed to tobacco smoke (smokers, SHS-exposed never-smokers) and differed from non-exposed never-smokers. In multivariate analysis, p16 hypermethylation was more prevalent in lung tumours from male than female patients (P = 0.018) and in squamous cell carcinomas than in adenocarcinomas (P = 0.025). Occurrence of TP53 mutation in the tumour was associated with hypermethylation of at least one gene (P = 0.027). In all, our data suggest that promoter hypermethylation pattern in SHS-exposed never-smokers resembles that observed in smokers. Association between TP53 mutation, a hallmark of smokers' lung cancer, and methylation of one or more of the lung cancer-related genes studied, provides further evidence for common tobacco smoke-related origin for both types of molecular alterations.

Risk factors for primary lung cancer among never smokers by gender in a matched case-control study

OBJECTIVE

Lung cancers that occur in never smokers differ from those that occur in smokers. We performed an analysis of potential epidemiological risk factors for lung cancer among never smokers.

METHODS

In this hospital-based matched case-control study, all 1,540 matched case-control pairs were Han Chinese in Taiwan. The data on demographic characteristics, smoking habit, exposure to environmental tobacco smoke, medical history of lung diseases, family history of lung cancer, and female characteristics were collected from a structured questionnaire. A multiple conditional logistic regression was used to estimate odds ratios and 95 % confidence intervals after adjusting for possible confounders.

RESULTS

Overall, several epidemiological factors of lung cancer in never smokers were different between males and females. For the female population, subjects who were exposed to environmental tobacco smoke (OR = 1.39, 95 % CI = 1.17-1.67) with a history of pulmonary tuberculosis and with family history of lung cancer in first-degree relatives (OR = 2.44, 95 % CI = 1.79-3.32) had higher risk of lung cancer, while subjects with a history of hormone replacement therapy and using fume extractors for those who cooked were protective. For the male population, only subjects with family history of lung cancer in first-degree relatives (OR = 2.77, 95 % CI = 1.53-5.01) were significantly associated with risk of lung cancer.

CONCLUSION

This study provides insights about the epidemiological factors of lung cancer in never smokers, adding to existing evidence that family history of lung cancer and environmental tobacco smoke may moderate lung cancer risk.

[Systematic review of studies of workplace exposure to environmental tobacco smoke and lung cancer risk]

背景与目的

已有的研究表明：工作环境烟草暴露与非吸烟人群肺癌发生有密切关系并不十分明确，本研究旨在探讨工作环境烟草暴露与非吸烟人群肺癌发生危险的关系。

方法

通过计算机检索Medline（1954年-2010年8月）、CENTRL（the Cochrane central register of controlledtrials）（2010 issue3）、EMBASE（1970年-2010年8月）中国生物医学文献数据库系统（CBM）（1978年-2010年8月）、中国期刊全文数据库（CNKI）（1979年-2010年8月）、中文科技期刊全文数据库（VIP）（1989年-2010年8月）等数据库，收集国内外公开发表的关于工作环境烟草暴露与非吸烟人群肺癌发生关系的研究文献，应用统计软件Stata 11.0进行数据分析，计算其合并优势比（odds ratio, OR）和95%置信区间（confdence interval, CI）。采用Begg法对发表偏倚进行量化检测。

结果

最终纳入分析的文章共有22篇，合并分析结果表明工作环境烟草暴露使非吸烟人群肺癌发生率增加了25%（OR=1.25, 95%CI: 1.13-1.39, P < 0.001），使非吸烟女性肺癌的发生率增加了22%（OR=1.22, 95%CI: 1.05-1.42, P=0.011）；工作环境烟草暴露导致非吸烟男性肺癌的发生率增加了54%，但无统计学意义（OR=1.54, 95%CI: 0.74-3.18, P=0.247）。

结论

工作环境烟草暴露是非吸烟人群肺癌发生的一个危险因素，非吸烟女性工作环境的烟草暴露与肺癌的发生关系密切。

Prior lung disease and lung cancer risk in an occupational-based cohort in Yunnan, China

We used the data from a prospective cohort study among tin miners in Yunnan, China to investigate whether prior lung disease is a risk factor for lung cancer. Information on prior lung disease was obtained from baseline questionnaires. The Cox proportional hazards model was used to examine the relationship between prior lung disease and lung cancer risk. From 1992 to 2001, a total of 502 lung cancer cases were confirmed among 9295 cohort participants. Prior chronic bronchitis was associated with an increase in lung cancer risk with an adjusted HR of 1.50 (95% CI: 1.24-1.81). There was an increased risk of developing squamous cell carcinoma in the setting of prior chronic bronchitis and small cell carcinoma in association with asthma with an adjusted HRs of 1.57 (95% CI: 1.19-2.09) and 2.56 (95% CI: 1.38-4.75), respectively. This prospective study provides further evidence that prior chronic bronchitis correlates with increased lung cancer risk, especially for squamous cell carcinoma. Asthma is associated with increased risk of small cell lung carcinoma.

Exposure to environmental tobacco smoke in childhood and incidence of cancer in adulthood in never smokers in the European Prospective Investigation into Cancer and Nutrition

The association between childhood environmental tobacco smoke (ETS) exposure and adult cancer risk is controversial; we examined this relationship in never smokers within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Over an average of 10 years, 8,372 cases of cancer were diagnosed in 112,430 never smokers in EPIC. Childhood ETS was self-reported by participants at baseline, along with other lifestyle factors. Hazard ratios (HR) for ETS exposure in childhood and their 95% confidence intervals (CI) were estimated by Cox proportional hazards models stratified by age, sex, and study center and adjusted for education, alcohol drinking, body mass index, physical activity, non-alcoholic energy intake, fruit and vegetable intake, and adulthood ETS exposure. Models were further adjusted for reproductive factors for female cancers, for meat intake for digestive system cancers, and for diabetes status for pancreatic cancer. No association was observed between childhood ETS exposure and overall cancer risks (HR = 0.97, 95% CI = 0.92-1.02), and for selected sites. The only exception was pancreatic cancer, as previously reported by Vrieling et al., among those who had been exposed daily in childhood (overall HR = 2.09, 95% CI = 1.14-3.84). In conclusion, childhood ETS exposure might not be a major risk factor for common cancers in adulthood.

Polymorphisms of MLH1 and MSH2 genes and the risk of lung cancer among never smokers

Mismatch repair (MMR) plays an important role in repairing nucleotide mismatches during DNA replication. Defects in MMR genes are associated with some sporadic tumors. MLH1 and MSH2 are two of the MMR genes. We conducted a case-control study to investigate the associations between the risk of lung cancer and genetic polymorphisms in the MLH1 and MSH2 genes. The SNP genotypes were determined in 730 lung cancer patients and 730 healthy controls that were frequency matched for the age, gender, and smoking status. Among the SNP polymorphisms, -93A>G (rs1800734), which is located in the promoter region of MLH1, was significantly associated with the risk of lung cancer. The GG genotype for MLH1 -93A>G was associated with a significantly increased risk of lung cancer compared with the AA genotype among the never-smoking group (adjusted OR=1.64, 95% CI=1.10-2.44; P=0.013). Consistently, the haplotype of MLH1 with one -93G risk allele was associated with the risk of lung cancer compared with the AA haplotype among the never-smoking group. Furthermore, the risk of MLH1 -93A>G polymorphism in the never-smoking group related to lung adenocarcinoma was modulated by environmental tobacco smoke (ETS) exposure status, with a significant gene-ETS interaction (P=0.042). No evidence was found of the association between MSH2 and the lung cancer risk. In conclusion, our data suggest that the MLH1 -93A>G polymorphism may contribute to the etiology of lung cancer, particularly in never smokers. This study also suggests that MLH1 -93A>G polymorphisms and ETS exposure have a role in the tumorigenesis of lung adenocarcinoma among never smokers.

Quantification of ETS exposure in hospitality workers who have never smoked

BACKGROUND

Environmental Tobacco Smoke (ETS) was classified as human carcinogen (K1) by the German Research Council in 1998. According to epidemiological studies, the relative risk especially for lung cancer might be twice as high in persons who have never smoked but who are in the highest exposure category, for example hospitality workers. In order to implement these results in the German regulations on occupational illnesses, a valid method is needed to retrospectively assess the cumulative ETS exposure in the hospitality environment.

METHODS

A literature-based review was carried out to locate a method that can be used for the German hospitality sector. Studies assessing ETS exposure using biological markers (for example urinary cotinine, DNA adducts) or questionnaires were excluded. Biological markers are not considered relevant as they assess exposure only over the last hours, weeks or months. Self-reported exposure based on questionnaires also does not seem adequate for medico-legal purposes. Therefore, retrospective exposure assessment should be based on mathematical models to approximate past exposure.

RESULTS

For this purpose a validated model developed by Repace and Lowrey was considered appropriate. It offers the possibility of retrospectively assessing exposure with existing parameters (such as environmental dimensions, average number of smokers, ventilation characteristics and duration of exposure). The relative risk of lung cancer can then be estimated based on the individual cumulative exposure of the worker.

CONCLUSION

In conclusion, having adapted it to the German hospitality sector, an existing mathematical model appears to be capable of approximating the cumulative exposure. However, the level of uncertainty of these approximations has to be taken into account, especially for diseases with a long latency period such as lung cancer.

Legislative smoking bans for reducing secondhand smoke exposure, smoking prevalence and tobacco consumption

BACKGROUND

Smoking bans have been implemented in a variety of settings, as well as being part of policy in many jurisdictions to protect the public and employees from the harmful effects of secondhand smoke (SHS). They also offer the potential to influence social norms and smoking behaviour of those populations they affect.

OBJECTIVES

To assess the extent to which legislation-based smoking bans or restrictions reduce exposure to SHS, help people who smoke to reduce tobacco consumption or lower smoking prevalence and affect the health of those in areas which have a ban or restriction in place.

SEARCH STRATEGY

We searched the Cochrane Tobacco Addiction Group Specialised Register, MEDLINE, EMBASE, PsycINFO, CINAHL, Conference Paper Index, and reference lists and bibliographies of included studies. We also checked websites of various organisations. Date of most recent search; July 1st 2009.

SELECTION CRITERIA

We considered studies that reported legislative smoking bans and restrictions affecting populations. The minimum standard was having a ban explicitly in the study and a minimum of six months follow-up for measures of smoking behaviour. We included randomized controlled trials, quasi-experimental studies (i.e. non-randomized controlled studies), controlled before and after studies, interrupted-time series as defined by the Cochrane Effective Practice and Organization of Care Group, and uncontrolled pre- and post-ban data.

DATA COLLECTION AND ANALYSIS

Characteristics and content of the interventions, participants, outcomes and methods of the included studies were extracted by one author and checked by a second. Because of heterogeneity in the design and content of the studies, we did not attempt a meta-analysis. We evaluated the studies using qualitative narrative synthesis.

MAIN RESULTS

There were 50 studies included in this review. Thirty-one studies reported exposure to secondhand smoke (SHS) with 19 studies measuring it using biomarkers. There was consistent evidence that smoking bans reduced exposure to SHS in workplaces, restaurants, pubs and in public places. There was a greater reduction in exposure to SHS in hospitality workers compared to the general population. We failed to detect any difference in self-reported exposure to SHS in cars. There was no change in either the prevalence or duration of reported exposure to SHS in the home as a result of implementing legislative bans. Twenty-three studies reported measures of active smoking, often as a co-variable rather than an end-point in itself, with no consistent evidence of a reduction in smoking prevalence attributable to the ban. Total tobacco consumption was reduced in studies where prevalence declined. Twenty-five studies reported health indicators as an outcome. Self-reported respiratory and sensory symptoms were measured in 12 studies, with lung function measured in five of them. There was consistent evidence of a reduction in hospital admissions for cardiac events as well as an improvement in some health indicators after the ban.

AUTHORS' CONCLUSIONS

Introduction of a legislative smoking ban does lead to a reduction in exposure to passive smoking. Hospitality workers experienced a greater reduction in exposure to SHS after implementing the ban compared to the general population. There is limited evidence about the impact on active smoking but the trend is downwards. There is some evidence of an improvement in health outcomes. The strongest evidence is the reduction seen in admissions for acute coronary syndrome. There is an increase in support for and compliance with smoking bans after the legislation.

ATM polymorphisms and risk of lung cancer among never smokers

The ataxia-telangiectasia mutated (ATM) gene, an important caretaker of overall genome stability, is thought to play a role in the development of human malignancy. Therefore, we hypothesized that sequence variants in ATM may influence the disposition to lung cancer. In this hospital-based matched case-control study, nine ATM single nucleotide polymorphisms (rs189037, rs228597, rs228592, rs664677, rs609261, rs599558, rs609429, rs227062, and rs664982) were genotyped in 730 lung cancer patients and 730 healthy controls. Pairwise linkage disequilibrium among nine polymorphisms in the ATM gene was very high. None of the main effects of any of the ATM polymorphisms were related to the risk of lung cancer. Interestingly, ATM polymorphisms were significantly associated with lung cancer among never smokers, and the association was modulated by low-level exposure to carcinogens such as environmental tobacco smoke. When the haplotypes of nine ATM polymorphism sites were studied, no overall association between ATM haplotypes and risk of lung cancer was found. However, the frequency distribution of haplotypes between lung cancer cases and controls was significant in the never smokers (P=0.009), demonstrating that haplotypes have a significant effect on the risk of lung cancer. In conclusion, we found that never smokers with sequence variants of the ATM gene may be at increased risk for lung cancer. Our data also suggest this association may be further modified by exposure to environmental tobacco smoke. This study suggests support to the literature that ATM polymorphisms and environmental tobacco smoke exposure have a role in lung carcinogenesis among never smokers.

Biomarkers in cancer epidemiology: an integrative approach

There are different reasons for the increase in the use of biomarkers in cancer epidemiology which is as follows: (i) the fact that the identification of new carcinogens, characterized by complex exposure circumstances and weak effects, has become increasingly difficult with traditional epidemiological approaches; (ii) the increasing understanding of mechanisms of carcinogenesis and (iii) technical developments in molecular biology and genetics. While a distinction is made between biomarkers of exposure, intermediate events, disease, outcome and susceptibility, their integration in a unique conceptual model is needed. The use of exposure biomarkers in cancer epidemiology aims at measuring the biologically relevant exposure more validly and precisely. In some instances, there is an obvious improvement in using an exposure biomarker, as in the case of urinary markers of aflatoxin and tobacco-specific nitrosamines. Intermediate (effect) biomarkers measure early--in general non-persistent--biological events that take place in the continuum between exposure and cancer development. These include cellular or tissue toxicity, chromosomal alterations, changes in DNA, RNA and protein expression and alterations in functions relevant to carcinogenesis (e.g. DNA repair, immunological response, etc.). The analysis of acquired TP53 mutations is an example of the potentially important. Biomarkers should be validated and consideration of sources of bias and confounding in molecular epidemiology studies should be no less stringent than in other types of epidemiological studies. The overarching goal is the integration of different types of biomarkers to derive risk and outcome profiles for healthy individuals as well as patients.

[Respiratory diseases related to passive smoking]

Passive smoking, measured in practice by using specific biomarkers, is a well known factor of morbidity and mortality. The main victims are children, often starting from conception, but adults are not spared. Many respiratory diseases are caused and/or worsened by passive smoking and environmental tobacco smoke (ETS) exposure can have serious health consequences that reduce life expectancy (sudden infant death, respiratory infections, asthma, chronic obstructive pulmonary diseases and lung cancer). Better knowledge of these risks has favourably influenced the legislation banning smoking in enclosed public places in France and in other countries. If one of the main objectives of this measure is to protect non-smokers as well as smokers, its rigorous application fits directly within the goals of prevention and treatment of tobacco dependency.

Relationship of eating behavior to long-term weight change and body mass index: the Healthy Twin study

This study examined the relationships of the Dutch Eating Behavior Questionnaire (DEBQ) subscales with weight change and with current body mass index (BMI). A total of 1576 adult twins and their families (578 Korean men, 998 Korean women, age 44.5+/-12.9 years) participating in the Healthy Twin study completed a survey that included the DEBQ, self-reported weight at 20 years old and intentionally lost weight over the past 4 years. Their anthropometric measurements were taken. Using the general linear models, restrained eating was positively associated with weight gain from 20 years old to current age [beta (B) =1.01, standard error (SE)=0.27, p<0.001], and with current BMI (B=0.33, SE=0.09, p<0.001) after adjusting for demographics, health-related behaviors, energy intake, and emotional and external eating. Likewise, emotional eating was positively associated with weight gain (B=0.83, SE=0.28, p<0.001), and with current BMI (B=0.35, SE=0.10, p=0.003) after adjusting those factors, and restrained and external eating. However, external eating was not associated with both outcomes. In conclusion, high restrained eating or emotional eating may be indicators for long-term weight gain and high BMI in Korean twins and their families.

Environmental tobacco smoke and lung cancer among Chinese nonsmoking males: might adenocarcinoma be the culprit?

No studies have specifically reported the association of lung adenocarcinoma with environmental tobacco smoke (ETS) exposure among nonsmoking males. The objective of this study was to examine the exposure-response relation between ETS exposure and lung cancer among nonsmoking males. In particular, the association with adenocarcinoma of the lung was studied. This is a population-based, case-referent study in Hong Kong during 2004-2006. A total of 132 Chinese male nonsmokers with newly diagnosed primary lung cancer and 536 nonsmoking community referents were interviewed about ETS exposures from the household and/or workplace, including ever ETS exposure, sources of exposure, number of smoking cohabitants/coworkers, and smoker-years. Univariate logistic regression analyses showed a weak association between all lung cancers and ever ETS exposure from the household and/or workplace (odds ratio (OR) = 1.11, 95% confidence interval (CI): 0.74, 1.67), but an increased risk was restricted to adenocarcinoma (OR = 1.68, 95% CI: 1.00, 2.38). After adjustment for family cancer history and other confounders, excess risk (OR = 1.62, 95% CI: 0.91, 2.88) still persisted for adenocarcinoma, although it was no longer statistically significant. Exposure-response relations for adenocarcinoma were found with increasing levels of all ETS indices when exposures from the household and workplaces were combined. The consistent exposure-response relations between ETS exposures and adenocarcinoma suggested a probable causal link, which would have to be confirmed by future larger studies.

Hookah (Shisha, Narghile) Smoking and Environmental Tobacco Smoke (ETS). A critical review of the relevant literature and the public health consequences

Hookah (narghile, shisha, "water-pipe") smoking is now seen by public health officials as a global tobacco epidemic. Cigarette Environmental Tobacco Smoke (ETS) is classically understood as a combination of Side-Stream Smoke (SSS) and Exhaled Main-Stream Smoke (EMSS), both diluted and aged. Some of the corresponding cigarette studies have served as the scientific basis for stringent legislation on indoor smoking across the world. Interestingly, one of the distinctive traits of the hookah device is that it generates almost no SSS. Indeed, its ETS is made up almost exclusively by the smoke exhaled by the smoker (EMSS), i.e. which has been filtered by the hookah at the level of the bowl, inside the water, along the hose and then by the smoker's respiratory tract itself. The present paper reviews the sparse and scattered scientific evidence available about hookah EMSS and the corresponding inferences that can be drawn from the composition of cigarette EMSS. The reviewed literature shows that most of hookah ETS is made up of EMSS and that the latter qualitatively differs from MSS. Keeping in mind that the first victim of passive smoking is the active smoker her/himself, the toxicity of hookah ETS for non-smokers should not be overestimated and hyped in an unscientific way.

Cigarette smoking and changing trends of lung cancer incidence by histological subtype among Chinese male population

We analyzed the time trends of lung cancer by histological subtype in Hong Kong during 1991-2005, and examined how the time trends were influenced by the effects of birth cohort and calendar period of diagnosis. Cancer incidence data were obtained from Hong Kong Cancer Registry and population data from Census and Statistics Department. Age-standardized incidence rates were computed by the direct method using WHO 1966 standard population as reference. Period and cohort effects were assessed by using two separate Poisson regression models adjusting for age. From 1991 to 2005, the incidence rates in Hong Kong Chinese males decreased steadily. The decline in overall lung cancer incidence rates was limited primarily to the decrease in squamous cell carcinoma, which could be explained by the decreasing trend of cigarette smoking. Adenocarcinoma had been the most predominant histological subtype all along. The relatively horizontal trend of adenocarcinoma and the lack of cohort effect implied the important roles of gene-environment interaction and/or the use of low-tar and filter tip cigarettes. Our study suggests that different histological subtypes may represent different disease entities with perhaps some distinct risk factors. The hypotheses generated from this ecological study will need confirmation by subsequent analytic studies.

Role of alpha7-nicotinic acetylcholine receptor in human non-small cell lung cancer proliferation

OBJECTIVES

Lung cancer is the most common cause of cancer death in the world. Cigarette smoking represents the major risk factor. Nicotine, an active component of cigarettes, can induce cell proliferation, angiogenesis and apoptosis resistance. All these events are mediated through the nicotinic acetylcholine receptor (nAChR) expressed on lung cancer cells. We speculate that new insights into the pathophysiological roles of nAChR may lead to new therapeutic avenues to reduce non-small cell lung cancer (NSCLC) tumour growth.

MATERIALS AND METHODS

Human samples of NSCLC, cell lines and mouse models were utilized in Western blotting, reverse transcriptase polymerase chain reaction and apoptosis studies.

RESULTS

Human NSCLC tissues expressed alpha7-nAChR. This expression was higher in smoking patients with squamous carcinomas than those with adenocarcinomas and in male smoking patients than in females. All the data support the hypothesis that major expression of alpha7-nAChR is related to major activation of the Rb-Raf-1/phospho-ERK/phospho-p90RSK pathway. alpha7-nAChR antagonists, via mitochondria associated apoptosis, inhibited proliferation of human NSCLC primary and established cells. Nicotine stimulates tumour growth in a murine model, A549 cells orthotopically grafted. The effects of nicotine were associated with increases in phospho-ERK in tumours. Proliferation effects of nicotine could be blocked by inhibition of alpha7-nAChR by the high affinity ligand alpha-cobratoxin.

CONCLUSION

These results showed that alpha7-nAChR plays an important role in NSCLC cell growth and tumour progression as well as in cell death.

Incense use and respiratory tract carcinomas: a prospective cohort study

BACKGROUND

Incense use is an integral part of daily life in large parts of Asia. The burning of incense is a powerful producer of particulate matter and the smoke contains a multitude of well-characterized carcinogens. However, to the authors' knowledge, no convincing association has been reported between exposure to incense smoke and the development of cancer. Therefore, the relation between incense use and the risk of respiratory tract carcinomas was analyzed in a prospective cohort study.

METHODS

Between 1993 and 1998, a population-based cohort of 61,320 Singapore Chinese who were free of cancer and ages 45 to 74 years completed a comprehensive interview regarding living conditions and dietary and lifestyle factors. Through linkage to population-based registries, the cohort was followed through 2005 and cancer occurrence determined. The relative risk for these cancers associated with incense use was estimated using a Cox proportional hazards model.

RESULTS

A total of 325 upper respiratory tract (UPT) carcinomas and 821 lung carcinomas were observed during follow-up. Incense use was associated with a significantly increased risk of UPT carcinomas other than nasopharyngeal, whereas no overall effect was observed on lung cancer. The duration and intensity of incense use were associated with an increased risk of squamous cell carcinomas in the entire respiratory tract (P for trend = .004), whereas there was no significant association noted between incense use and nonsquamous cell carcinomas. The relative risk of squamous cell carcinomas among long-term incense users was 1.8 (95% confidence interval [95% CI], 1.2-2.6; P = .004) in the entire respiratory tract.

CONCLUSIONS

The results of the current study indicate that long-term use of incense is associated with an increased risk of squamous cell carcinoma of the respiratory tract.

Reliability and accuracy of interview data in non-smoking female lung cancer case-control study

Background

Valid interview data is critical to the final results of the study. The purpose of this study was to investigate the reliability of epidemiological data obtained in non-smoking female lung cancer case-control study in China.

Methods

Fifty-six pairs of cases and controls, 10% percent of all the collected subjects were re-interviewed by three interviewers who underwent identical standardized training. A limited number of questions included in the original survey were asked again, the responses from the re-interview were compared with the original interview. Kappa was calculated by negative rates of agreement, positive rates of agreement and total rates of agreement to the accordance degree between the two interviews.

Results

The Kappa values were all more than 0.5 in all the studied indexes. The Kappa values descended from 0.92 in family history of cancer to 0.56 in oral contraception use. Errors in collecting and classifying data did occur, and were especially common for complicated clinical events, such as a drug exposure occurring many years before.

Conclusion

We identified four sources of this variability, three in collecting the data, and one in coding. As a result of these findings, strategies are proposed for improving the quality of interview data obtained in epidemiological research. Before finding a good solution, the strategy of data collecting and coding should be simple and easy to inspect.

Women and lung cancer: clinical and molecular profiling as a determinate for treatment decisions: a literature review

In the past decade the incidence of lung cancer among women has risen, whereas among men it has slightly declined. Important differences in lung cancer have been demonstrated between men and women, although many areas still remain controversial. Some biologic differences may justify the increase in response of women to therapy for lung cancer and can partially explain the improved survival of women compared with men. We extensively reviewed the published scientific literature on this topic in order to investigate the clinical and genetic profiling underlying lung cancer in women and to use this information as a tool for medical therapy.