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

Family history of cancer and lung cancer: Utility of big data and artificial intelligence for exploring the role of genetic risk

OBJECTIVES

Lung Cancer (LC) is a multifactorial disease for which the role of genetic susceptibility has become increasingly relevant. Our aim was to use artificial intelligence (AI) to analyze differences between patients with LC based on family history of cancer (FHC).

MATERIALS AND METHODS

From August 2016 to June 2020 clinical information was obtained from Thoracic Tumors Registry (TTR), a nationwide database sponsored by the Spanish Lung Cancer Group. In addition to descriptive statistical analysis, an AI-assisted analysis was performed. The German Technical Information Library supported the merging of data from the electronic medical records and database of the TTR. The results of the AI-assisted analysis were reported using Knowledge Graph, Unified Schema and descriptive and predictive analyses.

RESULTS

Analyses were performed in two phases: first, conventional statistical analysis including 11,684 patients of those 5,806 had FHC. Median overall survival (OS) for the global population was 23 months (CI 95 %: 21.39-24.61) in patients with FHC versus 21 months (CI 95 %: 19.53-22.48) in patients without FHC (NFHC), p < 0.001. The second AI-assisted analysis included 5,788 patients of those 939 had FHC. 58.48 % of women with FHC had LC. 9.53 % of patients had an EGFR or HER2 mutation or ALK translocation and at least one relative with cancer. A family history of LC was associated with an increased risk of smoking-related LC. Non-smokers with a family history of LC were more likely to have an EGFR mutation in NSCLC. In Bayesian network analysis, 55 % of patients with a family history of LC and never-smokers had an EGFR mutation.

CONCLUSION

In our population, the incidence of LC in patients with a FHC is higher in women and younger patients. FHC is a risk factor and predictor of LC development, especially in people ≤ 50 years. These results were confirmed by conventional statistics and AI-assisted analysis.

Exposure to second-hand smoke and risk of lung cancer among Iranian population: A multicenter case-control study

OBJECTIVE

Despite the implementation of the WHO Framework Convention on Tobacco Control (FCTC) program in Iran, the regulation of second-hand smoke (SHS) exposure-an often-overlooked hazard-, still requires improvement. We employed a multi-center case-control study to investigate the association between exposure to secondhand smoke (SHS) from various tobacco products (cigarettes, water-pipes, pipes, and chopogh), opium use, and the risk of lung cancer.

METHOD

We included 627 lung cancer cases and 3477 controls. Exposure to SHS tobacco and SHS opium was collected through a questionnaire. We used mixed-model logistic regressions to estimate odds ratios (ORs) and 95% confidence intervals (CI).

RESULT

Among the overall population exposed to second-hand tobacco smoke (SHTS), the odds ratio (OR) compared to those never exposed was 1.35 (95% CI: 1.08-1.71). Never smokers who were ever exposed to second-hand tobacco smoke (SHTS) had 1.69-fold risk of lung cancer compared to those who were never exposed (95% CI: 1.13-2.52). Exposure to SHTS between 2-3 per day (OR = 2.27, 95% CI: 1.13-4.53) and more than three hours per day (OR = 2.29, 95% CI: 1.20-4.37) can increase the risk of lung cancer compared with the no exposure group (P-trend <0.01). We did not observe any association between exposure to second-hand opium smoke (SHOS) and the risk of lung cancer, either in the overall population or among never-smokers.

CONCLUSION

Our study estimates the impact of second-hand tobacco smoke (SHTS) on lung cancer risk in both the overall population and never-smokers. Additional studies are required to evaluate the association between exposure to second-hand smoke from opium and other type of tobacco, including water-pipe and the risk of lung cancer.

Semi-quantitative assessment of environmental tobacco smoke exposure and its association with the development of oral squamous cell carcinoma: A pilot study

INTRODUCTION

Two known major risk factors for oral squamous cell carcinoma are smoking and alcohol consumption. Environmental tobacco smoke (also known as secondhand smoke) has been proven to be associated with the occurrence of lung and breast carcinoma. This study aimed to assess exposure to environmental tobacco smoke and its association with the development of oral squamous cell carcinomas.

METHODS

Using a standardized questionnaire, 165 cases and 167 controls were asked about their demographic data and risk behaviors, including environmental tobacco smoke exposure. An environmental tobacco smoke score (ETS-score) was developed to semi-quantitatively record the previous exposure to ETS. Statistical analyses were performed with χ² test or Fishers exact test, and with ANOVA or Welch's t-test as appropriate. An analysis was done using multiple logistic regression.

RESULTS

Cases had a significantly increased previous exposure to environmental tobacco smoke compared to the controls (ETS-score: 36.69 ± 26.34 vs 13.92 ± 12.44; p<0.0001). Comparing only the groups without additional active risk factors, exposure to environmental tobacco smoke was associated with a more than threefold higher likelihood of oral squamous cell carcinoma (OR=3.47; 95% CI: 1.31-10.55). Statistically significant differences in ETS-score were found for different tumor locations (p=0.0012) and different histopathological gradings (p=0.0399). A multiple logistic regression analysis confirmed exposure to environmental tobacco smoke as an independent risk factor for the development of oral squamous cell carcinomas (p<0.0001).

CONCLUSIONS

Environmental tobacco smoke is an important but yet underestimated risk factor for the development of oral squamous cell carcinomas. Further studies are needed to confirm the results, including the usefulness of the developed environmental tobacco smoke score for exposure.

Low-dose computed tomography for lung cancer screening in Anhui, China: A randomized controlled trial

Background

Lung cancer is the leading cause of cancer-related death worldwide, with risk factors such as age and smoking. Low-dose computed tomography screening can reduce lung cancer mortality. However, its effectiveness in Asian populations remains unclear. Most Asian women with lung cancer are non-smokers who have not been screened. We conducted a randomized controlled trial to evaluate the performance of low-dose computed tomography screening in a Chinese population, including high-risk smokers and non-smokers exposed to passive smoking. The baseline data are reported in this study.

Methods

Between May and December 2019, eligible participants were randomized in a ratio of 1:1:1 to a screening (two arms) or control cohort. Non-calcified nodules/masses with a diameter >4 mm on low-dose computed tomography were considered positive findings.

Results

In total, 600 patients (mean age, 59.1 ± 6.9 years) underwent low-dose computed tomography. Women accounted for 31.5% (189/600) of patients; 89.9% (170/189) were non-smokers/passive smokers. At baseline, the incidence of lung cancer was 1.8% (11/600). The incidence of lung cancer was significantly lower in smokers than in female non-smokers/passive smokers (1.0% [4/415] vs. 4.1% [7/170], respectively; P=0.017). Stage 0-I lung cancer accounted for 90.9% (10/11) of cases.

Conclusions

We demonstrate the importance of including active smokers and female non-smokers/passive smokers in lung cancer screening programs. Further studies are needed to explore the risk factors, and long-term cost-benefit of screening Asian non-smoking women.

Clinical trial registration

http://chictr.org.cn/showproj.aspx?proj=39003, identifier ChiCTR1900023197.

Solid Fuel, Secondhand Smoke, and Lung Cancer Mortality: A Prospective Cohort of 323,794 Chinese Never-Smokers

Rationale: Household air pollution and secondhand tobacco smoke are known carcinogens for lung cancer, but large-scale estimates of the relationship with lung cancer mortality are lacking. Objectives: Using the large-scale cohort China Kadoorie Biobank, we prospectively investigated associations between these two risk factors and lung cancer death among never-smokers. Methods: The Biobank recruited 512,715 adults aged 30-79 years from 10 regions in China during 2004-2008. Self-reported never-smoking participants were followed up to December 31, 2016, with linkage to mortality data. Total duration of exposure to household air pollution was calculated from self-reported domestic solid fuel use. Exposure to secondhand tobacco smoke was ascertained using exposure at home and/or other places. Hazard ratios and 95% confidence intervals for associations between these two exposures and lung cancer death were estimated using Cox regression, adjusting for key confounders. Measurements and Main Results: There were 979 lung cancer deaths among 323,794 never-smoking participants without a previous cancer diagnosis during 10.2 years of follow-up. There was a log-linear positive association between exposure to household air pollution and lung cancer death, with a 4% increased risk per 5-year increment of exposure (hazard ratio = 1.04; 95% confidence interval = 1.01-1.06; P trend = 0.0034), and participants with 40.1-50.0 years of exposure had the highest risk compared with the never-exposed (hazard ratio = 1.53; 95% confidence interval = 1.13-2.07). The association was largely consistent across various subgroups. No significant association was found between secondhand smoke and lung cancer death. Conclusions: This cohort study provides new prospective evidence suggesting that domestic solid fuel use is associated with lung cancer death among never-smokers.

Current cancer burden in China: epidemiology, etiology, and prevention

Cancer has become the most common cause of death in China. Owing to rapid economic development, improved livelihood, and shifts in risk factors, cancer epidemiology has experienced substantial changes during the past several decades. In this review, we aim to describe the current cancer epidemiology of the main types of cancer in China, report major risk factors associated with cancer development, and summarize the contributions of the Chinese government to controlling the cancer burden. A total of 4,064,000 new cases were diagnosed in China in 2016. The most frequent types are lung cancer (828,100; 20.4%), colorectal cancer (408,000; 10.0%), and gastric cancer (396,500; 9.8%). Lung (657,000; 27.2%), liver (336,400, 13.9%), and stomach (288,500; 12.0%) cancers are the 3 most deadly cancers in the general population. The 5-year survival rate for cancer has dramatically increased in recent decades. However, liver and particularly pancreatic cancers still have the poorest prognosis. The main modifiable risk factors associated with cancer development include infectious agents, smoking, alcohol consumption, obesity, unhealthful dietary habits, and inadequate physical activity. The Chinese government has made unremitting efforts to decrease the cancer burden, including cancer education and investment in cancer screening programs.

Evaluating risk factors for lung cancer among never-smoking individuals using two Australian studies

PURPOSE

Lung cancer (LC) in never-smoking individuals would rank as Australia's eighth most deadly cancer, yet risk factors remain uncertain. We investigated demographic, lifestyle and health-related exposures for LC among never-smoking Australians.

METHODS

Using the prospective 45 and Up Study with 267,153 New South Wales (NSW) residents aged ≥ 45 years at recruitment (2006-2009), we quantified the relationship of 20 potential exposures with LC among cancer-free participants at baseline who self-reported never smoking. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) for incident LC were estimated using Cox regression. The NSW Cancer, Lifestyle and Evaluation of Risk (CLEAR) Study, a case-control study including 10,781 NSW residents aged ≥ 18 years (2006-2014), was used to examine 16 potential LC exposures among cancer-free never-smoking participants. Adjusted odds ratios (OR) and 95% CI of LC were estimated using logistic regression.

RESULTS

There were 226 LC cases among 132,354 cancer-free 45 and Up Study participants who reported never smoking, with a median follow-up of 5.41 years. The CLEAR Study had 58 LC cases and 1316 cancer-free controls who had never smoked. Analyses of both datasets showed that Asian-born participants had a higher risk of LC than those born elsewhere: cohort, adjusted HR = 2.83 (95% CI 1.64-4.89) and case-control, adjusted OR = 3.78 (1.19-12.05). No significant association with LC was found for other exposures.

CONCLUSION

Our findings support the growing evidence that never-smoking, Asian-born individuals are at higher risk of developing LC than those born elsewhere. Ethnicity could be considered when assessing potential LC risk among never-smoking individuals.

Risk Assessment of Passive Smoking Based on Analysis of Hair Nicotine and Cotinine as Exposure Biomarkers by In-Tube Solid-Phase Microextraction Coupled On-Line to LC-MS/MS

Passive smoking due to environmental tobacco smoke is a serious public health concern because it increases the risk of lung cancer and cardiovascular disease. However, the current status and effect of passive smoking in various lifestyles are not fully understood. In this study, we measured hair nicotine and cotinine levels as exposure biomarkers in non-smokers and assessed the risk from the actual situation of passive smoking in different lifestyle environments. Nicotine and cotinine contents in hair samples of 110 non-smoker subjects were measured by in-tube solid-phase microextraction with on-line coupling to liquid chromatography-tandem mass spectrometry, and self-reported lifestyle questionnaires were completed by the subjects. Nicotine and cotinine were detected at concentrations of 1.38 ng mg⁻¹ and 12.8 pg mg⁻¹ respectively in the hair of non-smokers, with levels significantly higher in subjects who reported being sensitive to tobacco smoke exposure. These levels were also affected by type of food intake and cooking method. Nicotine and cotinine in hair are useful biomarkers for assessing the effects of passive smoking on long-term exposure to environmental tobacco smoke, and our analytical methods can measure these exposure levels in people who are unaware of passive smoking. The results of this study suggest that the environment and places of tobacco smoke exposure and the lifestyle behaviors therein are important for the health effects of passive smoking.

Lung cancer risk in never-smokers: An overview of environmental and genetic factors

Lung cancer is the leading cause of cancer-related mortality globally, accounting for 1.8 million deaths in 2020. While the vast majority are caused by tobacco smoking, 15%-25% of all lung cancer cases occur in lifelong never-smokers. The International Agency for Research on Cancer (IARC) has classified multiple agents with sufficient evidence for lung carcinogenesis in humans, which include tobacco smoking, as well as several environmental exposures such as radon, second-hand tobacco smoke, outdoor air pollution, household combustion of coal and several occupational hazards. However, the IARC evaluation had not been stratified based on smoking status, and notably lung cancer in never-smokers (LCINS) has different epidemiological, clinicopathologic and molecular characteristics from lung cancer in ever-smokers. Among several risk factors proposed for the development of LCINS, environmental factors have the most available evidence for their association with LCINS and their roles cannot be overemphasized. Additionally, while initial genetic studies largely focused on lung cancer as a whole, recent studies have also identified genetic risk factors for LCINS. This article presents an overview of several environmental factors associated with LCINS, and some of the emerging evidence for genetic factors associated with LCINS. An increased understanding of the risk factors associated with LCINS not only helps to evaluate a never-smoker's personal risk for lung cancer, but also has important public health implications for the prevention and early detection of the disease. Conclusive evidence on causal associations could inform longer-term policy reform in a range of areas including occupational health and safety, urban design, energy use and particle emissions, and the importance of considering the impacts of second-hand smoke in tobacco control policy.

Cigarette smoke-associated inflammation impairs bone remodeling through NFκB activation

Background

Cigarette smoking constitutes a major lifestyle risk factor for osteoporosis and hip fracture. It is reported to impair the outcome of many clinical procedures, such as wound infection treatment and fracture healing. Importantly, although several studies have already demonstrated the negative correlation between cigarette consume and impaired bone homeostasis, there is still a poor understanding of how does smoking affect bone health, due to the lack of an adequately designed animal model. Our goal was to determine that cigarette smoke exposure impairs the dynamic bone remodeling process through induction of bone resorption and inhibition of bone formation.

Methods

We developed cigarette smoke exposure protocols exposing mice to environmental smoking for 10 days or 3 months to determine acute and chronic smoke exposure effects. We used these models, to demonstrate the effect of smoking exposure on the cellular and molecular changes of bone remodeling and correlate these early alterations with subsequent bone structure changes measured by microCT and pQCT. We examined the bone phenotype alterations in vivo and ex vivo in the acute and chronic smoke exposure mice by measuring bone mineral density and bone histomorphometry. Further, we measured osteoclast and osteoblast differentiation gene expression levels in each group. The function changes of osteoclast or osteoblast were evaluated.

Results

Smoke exposure caused a significant imbalance between bone resorption and bone formation. A 10-day exposure to cigarette smoke sufficiently and effectively induced osteoclast activity, leading to the inhibition of osteoblast differentiation, although it did not immediately alter bone structure as demonstrated in mice exposed to smoke for 3 months. Cigarette smoke exposure also induced DNA-binding activity of nuclear factor kappaB (NFκB) in osteoclasts, which subsequently gave rise to changes in bone remodeling-related gene expression.

Conclusions

Our findings suggest that smoke exposure induces RANKL activation-mediated by NFκB, which could be a “smoke sensor” for bone remodeling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02836-z.

Age at first birth and lung cancer: a two-sample Mendelian randomization study

Background

Growing evidence suggests that female reproductive factors, like age at first birth (AFB), may play a potential role in the progression of lung cancer (LC). However, previous studies are susceptible to confounding factors, inadequate attention to variation by histology or reverse causality. Few studies have comprehensively evaluated their association and the causal effect remains unclear.

Methods

We aimed to determine whether AFB is causally correlated with the risk of LC, by means of utilizing aggregated data from the large genome-wide association studies conducted on AFB (251,151 individuals) and data of LC from International Lung and Cancer Consortium (ILCCO, 11,348 cases and 15,861 controls). We used 10 AFB-related single nucleotide polymorphisms as instrument variables and applied several two-sample Mendelian randomization (MR) methods. Secondary results according to different histological subtypes of lung cancer were also implemented.

Results

Conventional inverse-variance weighted method indicated that genetic predisposition towards number unit (1 year) increase of AFB was associated with a 18% lower risk of LC [odds ratio (OR) =0.82, 95% confidence interval (CI): 0.69–0.97; P=0.029]. When results were examined by histotypes, an inverse association was observed between genetically predisposed number unit (1 year) increase of AFB and lung adenocarcinoma (OR =0.75, 95% CI: 0.59–0.97, P=0.017) but not with squamous cell lung cancer (OR =0.77, 95% CI: 0.57–1.05, P=0.103). The results demonstrated no association between number unit decrease of AFB and LC. Pleiotropy was not presented through sensitivity analyses including MR pleiotropy residual sum and outlier test (P=0.412). Genetic predisposition towards older AFB was additionally associated with longer years of schooling (OR =1.12, 95% CI: 1.08–1.16, P<0.001), lower body mass index (OR =0.93, 95% CI: 0.88–0.98, P=0.004) and less alcohol consumption (OR =0.99, 95% CI: 0.99–1.00, P=0.004).

Conclusions

Our study suggested that older AFB was a causal protective factor in the progression of LC. Further studies elucidating the potential mechanisms are needed.

Environmental Risk Factors and Health: An Umbrella Review of Meta-Analyses

Background: Environmental health is a growing area of knowledge, continually increasing and updating the body of evidence linking the environment to human health. Aim: This study summarizes the epidemiological evidence on environmental risk factors from meta-analyses through an umbrella review. Methods: An umbrella review was conducted on meta-analyses of cohort, case-control, case-crossover, and time-series studies that evaluated the associations between environmental risk factors and health outcomes defined as incidence, prevalence, and mortality. The specific search strategy was designed in PubMed using free text and Medical Subject Headings (MeSH) terms related to risk factors, environment, health outcomes, observational studies, and meta-analysis. The search was limited to English, Spanish, and French published articles and studies on humans. The search was conducted on September 20, 2020. Risk factors were defined as any attribute, characteristic, or exposure of an individual that increases the likelihood of developing a disease or death. The environment was defined as the external elements and conditions that surround, influence, and affect a human organism or population’s life and development. The environment definition included the physical environment such as nature, built environment, or pollution, but not the social environment. We excluded occupational exposures, microorganisms, water, sanitation and hygiene (WASH), behavioral risk factors, and no-natural disasters. Results: This umbrella review found 197 associations among 69 environmental exposures and 83 diseases and death causes reported in 103 publications. The environmental factors found in this review were air pollution, environmental tobacco smoke, heavy metals, chemicals, ambient temperature, noise, radiation, and urban residential surroundings. Among these, we identified 65 environmental exposures defined as risk factors and 4 environmental protective factors. In terms of study design, 57 included cohort and/or case-control studies, and 46 included time-series and/or case-crossover studies. In terms of the study population, 21 included children, and the rest included adult population and both sexes. In this review, the largest body of evidence was found in air pollution (91 associations among 14 air pollution definitions and 34 diseases and mortality diagnoses), followed by environmental tobacco smoke with 24 associations. Chemicals (including pesticides) were the third larger group of environmental exposures found among the meta-analyses included, with 19 associations. Conclusion: Environmental exposures are an important health determinant. This review provides an overview of an evolving research area and should be used as a complementary tool to understand the connections between the environment and human health. The evidence presented by this review should help to design public health interventions and the implementation of health in all policies approach aiming to improve populational health.

The fraction of lung cancer attributable to smoking in the Norwegian Women and Cancer (NOWAC) Study

Background

We examined the association between active and passive smoking and lung cancer risk and the population attributable fraction (PAF) of lung cancer due to active smoking, in the Norwegian Women and Cancer Study, a nationally representative prospective cohort study.

Methods

We followed 142,508 women, aged 31–70 years, who completed a baseline questionnaire between 1991 and 2007, through linkages to national registries through December 2015. We used Cox proportional hazards models, to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). We calculated PAF to indicate what proportion of lung cancer cases could have been prevented in the absence of smoking.

Results

During the more than 2.3 million person-years of observation, we ascertained 1507 lung cancer cases. Compared with never smokers, current (HR 13.88, 95% CI 10.18–18.91) smokers had significantly increased risk of lung cancer. Female never smokers exposed to passive smoking had a 1.3-fold (HR 1.34, 95% CI 0.89–2.01) non- significantly increased risk of lung cancer, compared with never smokers. The PAF of lung cancer was 85.3% (95% CI 80.0–89.2).

Conclusion

More than 8 in 10 lung cancer cases could have been avoided in Norway, if the women did not smoke.

Lung cancer in women in 21th century

Lung cancer is the first cause of death from malignant disease. The distressing epidemiological data show the increasing female to male incidence ratio for this tumor. A high incidence of lung cancer in never smokers with importance of environmental agents makes a problem among women. Adenocarcinoma (ADC) is noted in women with increasing rate and ethnic background impacts female lung cancer with differences in the incidence of genetic aberrations. The conception of different hormonal status is taken into consideration as potential explanation of variant cancer biology and clinical manifestation in women and men. The impact of 17-β-estradiol, estrogen receptors, aromatase expression, pituitary sex hormones receptors in carcinogenesis with relation between estrogens and genetic aberrations are investigated. The response to newest therapies among female is also different than in men. This overview summarizes currently available evidence on the specificity of female lung cancer and presents the direction of necessary studies.

Clinical characteristics and work-up of small to intermediate-sized pulmonary nodules in a Chinese dedicated cancer hospital

Objectives: To evaluate the characteristics and work-up of small to intermediate-sized pulmonary nodules in a Chinese dedicated cancer hospital. Methods: Patients with pulmonary nodules 4-25 mm in diameter detected via computed tomography (CT) in 2013 were consecutively included. The analysis was restricted to patients with a histological nodule diagnosis or a 2-year follow-up period without nodule growth confirming benign disease. Patient information was collected from hospital records. Results: Among the 314 nodules examined in 299 patients, 212 (67.5%) nodules in 206 (68.9%) patients were malignant. Compared to benign nodules, malignant nodules were larger (18.0 mm vs. 12.5 mm, P < 0.001), more often partly solid (16.0% vs. 4.7%, P < 0.001) and more often spiculated (72.2% vs. 41.2%, P < 0.001), with higher density in contrast-enhanced CT (67.0 HU vs. 57.5 HU, P = 0.015). Final diagnosis was based on surgery in 232 out of 314 (73.9%) nodules, 166 of which were identified as malignant [30 (18.1%) stage III or IV] and 66 as benign. In 36 nodules (11.5%), diagnosis was confirmed by biopsy and the remainder verified based on stability of nodule size at follow-up imaging (n = 46, 14.6%). Among 65 nodules subjected to gene (EGFR) mutation analyses, 28 (43.1%) cases (EGFR19 n = 13; EGFR21 n = 15) were identified as EGFR mutant and 37 (56.9%) as EGFR wild-type. Prior to surgery, the majority of patients [n = 194 (83.6%)] received a contrast-enhanced CT scan for staging of both malignant [n = 140 (84.3%)] and benign [n = 54 (81.8%)] nodules. Usage of positron emission tomography (PET)-CT was relatively uncommon [n = 38 (16.4%)]. Conclusions: CT-derived nodule assessment assists in diagnosis of small to intermediate- sized malignant pulmonary nodules. Currently, contrast-enhanced CT is commonly used as the sole diagnostic confirmation technique for pre-surgical staging, often resulting in surgery for late-stage disease and unnecessary surgery in cases of benign nodules.