Constituents of Household Air Pollution and Risk of Lung Cancer among Never-Smoking Women in Xuanwei and Fuyuan, China

Patterns and trends of mortality from metastatic colorectal cancer in Shanghai, China from 2005 to 2021: a population-based retrospective analysis

PURPOSE

Metastatic colorectal cancer (mCRC) is the leading cause of CRC deaths, however, the relative epidemiological research was insufficient. We aimed to analyze the patterns and trends of mortality of mCRC in Shanghai with a more complete system for monitoring the cause of death of the population and find potential methods to reduce the burden of CRC in China.

METHODS

Mortality data from 2005 to 2021 of mCRC deaths were obtained from the mortality registration system in Shanghai. We analyzed the crude mortality rates, age-standardized mortality rates, and rates of years of life lost (YLL rates) of mCRC. In addition, the trends were quantified using Joinpoint Regression software.

RESULTS

A total of 4,386 mCRC deaths were included, with 1,937 (44.16%) liver metastases and 1,061 (24.19%) lung metastases. The crude mortality rate and age-standardized mortality rate of mCRC were 9.09 per 105 person-years and 3.78 per 105 person-years, respectively. The YLL was 50,533.13 years, and the YLL rate was 104.67 per 105 person-years. The overall annual crude mortality rate of mCRC increased by 1.47% (95% CI 0.28-2.68%, P < 0.001) from 2005 to 2021. The crude mortality rate of mCRC increased by 3.20% per year (95% CI 1.80-4.70%, P < 0.001) from 2005 to 2013, but the trend of mortality growth remained stable from 2013 to 2021. The YLL rates remained stable between 2005 and 2021.

CONCLUSIONS

Population aging was the most likely factor responsible for the increase in CRC mortality in Pudong. Physical examinations and screenings for the elderly were possible reasons for reducing the burden of CRC in fast-growing regions.

Identification of core carcinogenic elements based on the age-standardized mortality rate of lung cancer in Xuanwei Formation coal in China

In this study, the core carcinogenic elements in Xuanwei Formation coal were identified. Thirty-one samples were collected based on the age-standardized mortality rate (ASMR) of lung cancer; Si, V, Cr, Co, Ni, As, Mo, Cd, Sb, Pb, and rare earth elements and yttrium (REYs) were analyzed and compared; multivariate statistical analyses (CA, PCA, and FDA) were performed; and comprehensive identification was carried out by combining multivariate statistical analyses with toxicology and mineralogy. The final results indicated that (1) the high-concentration Si, Ni, V, Cr, Co, and Cd in coal may have some potential carcinogenic risk. (2) The concentrations of Cr, Ni, As, Mo, Cd, and Pb meet the zoning characteristics of the ASMR, while the Si concentration is not completely consistent. (3) The REY distribution pattern in Longtan Formation coal is lower than that in Xuanwei Formation coal, indicating that the materials of these elements in coal are different. (5) The heatmap divides the sampling sites into two clusters and subtypes in accordance with carcinogenic zoning based on the ASMR. (6) PC1, PC2, and PC3 explain 62.629% of the total variance, identifying Co, Ni, As, Cd, Mo, Cr, and V. (7) Fisher discriminant analysis identifies Ni, Si, Cd, As, and Co based on the discriminant function. (8) Comprehensive identification reveals that Ni is the primary carcinogenic element, followed by Co, Cd, and Si in combination with toxicology. (9) The paragenesis of Si (nanoquartz), Ni, Co, and Cd is an interesting finding. In other words, carcinogenic elements Ni, Co, Cd, and Si and their paragenetic properties should receive more attention.

Origin, formation, and transformation of different forms of silica in Xuanwei Formation coal, China, and its' emerging environmental problem

The study on the origin of quartz and silica in Xuanwei Formation coal in Northwest Yunnan, China, is helpful to understand the relationship between quartz and silica and the high incidence of lung cancer from the root. To address these questions, the mineralogy and microscopic studies of silica in Xuanwei Formation coal were performed. The following results were obtained: (1) silica in the late Permian Xuanwei Formation coal seams originated from detrital input, early diagenesis, and late diagenesis. (2) A more significant contribution comes from early diagenesis, which contains abundant authigenic quartz and amorphous silica. (3) Quartz and silica from inorganic silicon are more symbiotic with kaolinite and from biogenic silicon with chamosite. (4) Three silica polymorphs in coal samples have been identified: opal-A (amorphous silica), opal-CT/-C (cristobalite/tridymite), and α quartz. (5) Opal-A is ubiquitous, while opal-CT/-C and α quartz are rare. (5) Opal-A is an amorphous and nontoxic ordinary silica. (6) Since the toxicity of amorphous silica and its presence in coal is an emerging topic, it should be continuously monitored.

Environmental factors and incidence of thyroid cancer in the world (1990-2019): an ecological study

Thyroid cancer (TC) is the most common endocrine malignancy. Environmental risk factors such as presence of pollutants in air as well as the combustion of fossil fuels or carbon as a cooking habit in closed environments inside houses affect thyroid hormonal homeostasis and diseases. This study aimed to estimate the association between environmental risk factors and the incidence of thyroid cancer worldwide from 1990 to 2019 including particulate pollutants coming from fossil fuels employed in closed environments. Data on the incidence of thyroid cancer and some environmental risk factors were extracted from the Global Cancer Observatory (GLOBOCAN) for 204 countries and territories from 1990 to 2019. Pearson's correlation coefficient was used to determine the correlation between the thyroid cancer incidence and environmental risk factors. Finally, a generalized additive model was fitted for modeling. R 3.5.0 was used for analysis of the data. The most relevant results showed that the age-standardized incidence rate (ASIR) of thyroid cancer has a positive and significant correlation with environmental air pollution by O3 (r=0.63, P value<0.001), by particulate matter pollution (r=0.23, P value<0.001), and by household PM2.5 air pollution (r=0.52, P value≤0.001). In contrast, the correlation between ASIR and high temperature (T>25.6°C) (r=-0.27, P value<0.001) is negative and significant. The modeling results showed that particulate matter pollution and O3 pollution and household PM2.5 air pollution which originated from solid fuels are risk factors for thyroid cancer. Therefore, more research in this field is necessary in areas with high levels of air pollution at the national and international levels.

Narrative review: respiratory tract microbiome and never smoking lung cancer

Background and Objective

The lung microbiome was previously thought to be a sterile environment where only gaseous exchange takes place, but recent studies have shown the presence of microbiota in the lung. This review investigates the current literature on the effects of an environmental driven dysbiosis on the healthy oral and respiratory microbiome and its relationship to lung cancer risk in never-smokers.

Methods

An online electronic search was performed on PubMed of all English-language literature using combinations of the following keywords: "lung cancer", "dysbiosis", "non-smokers", "oral microbiome", and "respiratory microbiome". All population-based studies reporting results on oral and/or respiratory microbiome in adults were considered for our narrative review.

Key Content and Findings

Metagenomic analyses have been performed on isolated samples from healthy participants and compared to samples from those with lung cancer. Research shows that a decrease in alpha diversity of microbes in the oral microbiome is associated with increased risk of lung cancer, along with differences in beta diversity in the sputum of lung cancer cases and healthy controls. Further, several studies have observed that significant changes in the abundance of genera such as increased abundance of Lactobacillales, Bacilli, and Firmicutes associated with an increased lung cancer risk among participants with exposure to certain household solid fuels.

Conclusions

These findings suggest potential carcinogenic processes such as increased inflammation associated with changes in flora. Additionally, studies showed that increase in certain taxa such as Bacteroides and Spirochetes might have a protective effect on lung cancer risk. The review also provides insight into how understanding the microbial changes can be beneficial for lung cancer treatment and disease-free survival. Larger studies in different populations need to be performed to strengthen the current associations between microbial diversity and lung cancer risk.

Exposure to smoky coal combustion emissions and leukocyte Alu retroelement copy number

Household air pollution (HAP) from indoor combustion of solid fuel is a global health burden that has been linked to multiple diseases including lung cancer. In Xuanwei, China, lung cancer rate for non-smoking women is among the highest in the world and largely attributed to high levels of polycyclic aromatic hydrocarbons (PAHs) that are produced from combustion of smoky (bituminous) coal. Alu retroelements, repetitive mobile DNA sequences that can somatically multiply and promote genomic instability have been associated with risk of lung cancer and diesel engine exhaust exposure. We conducted analyses for 160 non-smoking women in an exposure assessment study in Xuanwei, China with a repeat sample from 49 subjects. Quantitative PCR was used to measure Alu repeat copy number relative to albumin gene copy number (Alu/ALB ratio). Associations between clusters derived from predicted levels of 43 HAP constituents, 5-methylchrysene (5-MC), a PAH previously associated with lung cancer in Xuanwei and was selected a priori for analysis, and Alu repeats were analyzed using generalized estimating equations. A cluster of 31 PAHs reflecting current exposure was associated with increased Alu copy number (β:0.03 per standard deviation change; 95% confidence interval (CI):0.01,0.04; P-value = 2E-04). One compound within this cluster, 5-MC, was also associated with increased Alu copy number (P-value = 0.02). Our findings suggest that exposure to PAHs due to indoor smoky coal combustion may contribute to genomic instability. Additionally, our study provides further support for 5-MC as a prominent carcinogenic component of smoky coal emissions. Further studies are needed to replicate our findings.

Indoor wood-burning from stoves and fireplaces and incident lung cancer among Sister Study participants

BACKGROUND AND AIM

Epidemiological studies conducted mostly in low- and middle-income countries have found a positive association between household combustion of wood and lung cancer. However, most studies have been retrospective, and few have been conducted in the United States where indoor wood-burning usage patterns differ. We examined the association of exposure to indoor wood smoke from fireplaces and stoves with incident lung cancer in a U.S.-wide cohort of women.

METHODS

We included 50,226 women without prior lung cancer participating in the U.S.-based prospective Sister Study. At enrollment (2003-2009), women reported frequency of use of wood-burning stoves and/or fireplaces in their longest-lived adult residence. Cox regression was used to estimate adjusted hazard ratios (HRadj) and 95 % confidence intervals (CI) for the association between indoor wood-burning fireplace/stove use and incident lung cancer. Lung cancer was self-reported and confirmed with medical records.

RESULTS

During an average 11.3 years of follow-up, 347 medically confirmed lung cancer cases accrued. Overall, 62.3 % of the study population reported the presence of an indoor wood-burning fireplace/stove at their longest-lived adult residence and 20.6 % reported annual usage of ≥30 days/year. Compared to those without a wood-burning fireplace/stove, women who used their wood-burning fireplace/stove ≥30 days/year had an elevated rate of lung cancer (HRadj = 1.68; 95 % CI = 1.27, 2.20). In never smokers, positive associations were seen for use 1-29 days/year (HRadj = 1.64; 95 % CI = 0.87, 3.10) and ≥30 days/year (HRadj = 1.99; 95 % CI = 1.02, 3.89). Associations were also elevated across all income groups, in Northeastern, Western or Midwestern U.S. regions, and among those who lived in urban or rural/small town settings.

CONCLUSIONS

Our prospective analysis of a cohort of U.S. women found that increasing frequency of wood-burning indoor fireplace/stove usage was associated with incident lung cancer, even among never smokers.

Household air pollution and epigenetic aging in Xuanwei, China

BACKGROUND

Household air pollution (HAP) from indoor combustion of solid fuel is a global health burden linked to lung cancer. In Xuanwei, China, lung cancer rate for nonsmoking women is among the highest in the world and largely attributed to high levels of polycyclic aromatic hydrocarbons (PAHs) that are produced from combustion of smoky (bituminous) coal used for cooking and heating. Epigenetic age acceleration (EAA), a DNA methylation-based biomarker of aging, has been shown to be highly correlated with biological processes underlying the susceptibility of age-related diseases. We aim to assess the association between HAP exposure and EAA.

METHODS

We analyzed data from 106 never-smoking women from Xuanwei, China. Information on fuel type was collected using a questionnaire, and validated exposure models were used to predict levels of 43 HAP constituents. Exposure clusters were identified using hierarchical clustering. EAA was derived for five epigenetic clocks defined as the residuals resulting from regressing each clock on chronological age. We used generalized estimating equations to test associations between exposure clusters derived from predicted levels of HAP exposure, ambient 5-methylchrysene (5-MC), a PAH previously found to be associated with risk of lung cancer, and EAA, while accounting for repeated-measurements and confounders.

RESULTS

We observed an increase in GrimAge EAA for clusters with 31 and 33 PAHs reflecting current (β = 0.77 y per standard deviation (SD) increase, 95 % CI:0.36,1.19) and childhood (β = 0.92 y per SD, 95 % CI:0.40,1.45) exposure, respectively. 5-MC (ng/m3-year) was found to be associated with GrimAge EAA for current (β = 0.15 y, 95 % CI:0.05,0.25) and childhood (β = 0.30 y, 95 % CI:0.13,0.47) exposure.

CONCLUSIONS

Our findings suggest that exposure to PAHs from indoor smoky coal combustion, particularly 5-MC, is associated with GrimAge EAA, a biomarker of mortality.

Pollution levels and health risk assessment of potentially toxic metals of size-segregated particulate matter in rural residential areas of high lung cancer incidence in Fuyuan, China

The highest incidence and mortality rate of lung cancer in rural area of Fuyuan has been a research hotspot, and the pathogenesis is still unclear. Therefore, atmospheric particulate matters (APMs) samples were collected between 18 February and 01 March 2017, exploring water-soluble potentially toxic metals (WSPTMs) and water-soluble inorganic ionic species (WSIIs) levels, size distribution, sources, acidity and alkalinity, and potential carcinogenic and non-carcinogenic risks, hoping to provide scientific basic data to solve this problem. In our study, the average ratio of nitrate ion (NO₃^-)/sulfate ion (SO₄^2-) within PM_1.1, PM_1.1-2.0, PM_2.0-3.3, PM_3.3-7.0, and PM_>7.0 were 0.22, 0.18, 0.15, 0.34 and 0.36, respectively, that revealed that combustion sources contributed to PM were more significant. The anions in equilibrium (ANE) / cations in equilibrium (CAE) < 1 for all samples within PM_1.1, PM_2.0-3.3, PM_3.3-7.0 indicate that the APMs were alkaline, but PM_1.1-2.0 particulate matter shows weak acidity. SO₄^2- prefers to combine with NH₄⁺ to form (NH₄)₂SO₄, which hinders the formation of NH₄NO₃, the remaining SO₄^2- and NO₃^- to neutralize the K⁺, KNO₃ was formed at all particulate, however, K₂SO₄ can only be formed in PM_<3.3. Arsenic (As) and Selenium (Se) were identified as the most enriched WSPTMs in all PM sizes, predominantly from anthropogenic emissions, were suggested that coal combustion is a significant source of PM-bound WSPTMs. Total WSPTMs exhibited high total carcinogenic risks (TCR) values (9.98 × 10^-6, 1.06 × 10^-5, and 1.19 × 10^-5 for girls, boys and adults, respectively) in the smaller particles (< 1.1 μm). Se was considered as the major contributor (63.60%) to carcinogenic risk (CR) in PM_2.0 and had an inverse relationship with PM size that should be of prime concern.

Short-term association of air pollution with lung cancer mortality in Osaka, Japan

Long-term air pollution exposure has been linked to increased lung cancer mortality. However, little is known about whether day-to-day fluctuations in air pollution levels are in relation to lung cancer mortality, particularly in low-exposure settings. This study aimed to evaluate the short-term associations between air pollution and lung cancer mortality. Daily data on lung cancer mortality, fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO), and weather conditions were collected from Osaka Prefecture, Japan, from 2010 to 2014. Generalized linear models were combined with quasi-Poisson regression were applied to evaluate the associations between each air pollutant and lung cancer mortality after adjusting for potential confounders. Mean (standard deviation) concentrations of PM_2.5, NO₂, SO₂, and CO were 16.7 (8.6) μg/m³, 36.8 (14.2) μg/m³, 11.1 (4.0) μg/m³, and 0.51 (0.16) mg/m³, respectively. Interquartile range increases in concentrations of PM_2.5, NO₂, SO₂, and CO (2-d moving average) were associated with 2.65% (95% confidence intervals [CIs]: 0.96%-4.37%), 4.28% (95% CIs: 2.24%-6.36%), 3.35% (95% CIs: 1.03%-5.73%), and 4.60% (95% CIs: 2.19%-7.05%) increased risk of lung cancer mortality, respectively. Stratified analyses showed that the associations were strongest in the older population and men. Exposure‒response curves showed a continuously increasing mortality risk from lung cancer with elevation of air pollution levels, without discernible thresholds. In summary, we found evidence of increased lung cancer mortality in relation to short-term elevations in ambient air pollution. These findings may merit further research to better understand this issue.

A nationwide survey of polycyclic aromatic hydrocarbons (PAHs) in household dust in China: spatial distribution, sources, and health risk assessment

As a carrier of toxic substances, household dust has a great impact on human health. Here we collected 73 household dust samples from 27 provinces and 1 municipality in China to investigate the levels, spatial distribution, sources, and carcinogenic risk of 16 polycyclic aromatic hydrocarbons (PAHs). The total concentrations of 14 detected PAHs (∑₁₄ PAHs) ranged from 3.72 to 60,885 ng g^-1. High ∑₁₄ PAHs were found in Northeast and Southwest China. High molecular weights (HMW) PAHs (4-6 rings) were predominant PAHs in most dust samples, accounting for 93.6% of ∑₁₄ PAHs. Household fuel, cooking frequency, air conditioning, and smoking were the main factors influencing PAH concentrations in household dust. Principal component analysis model indicated that fossil combustion (81.5%) and biomass combustion and vehicle exhaust (8.1%) are the primary sources of PAHs. Positive matrix factorization model suggested that household cooking and heating contributed about 70% of ∑₁₄ PAHs, and smoking contributed another 30%. The values of benzo[a]pyrene equivalent in rural dust were found to be higher than those in urban dust. The sum of toxic equivalents (TEQs) of 14 PAHs were in range of 0.372-7241 ng g^-1, in which 7 HMW PAHs accounted for 98.0 ± 1.98% of the total TEQs. Monte Carlo Simulation showed a low to moderate potential carcinogenic risk of PAHs in household dusts. This study documents comprehensive information on human exposure to PAHs in household dust at a national-scale.

Emissions of Toxic Substances from Biomass Burning: A Review of Methods and Technical Influencing Factors

In the perspective of energy sustainability, biomass is the widely used renewable domestic energy with low cost and easy availability. Increasing studies have reported the health impacts of toxic substances from biomass burning emissions. To make proper use of biomass as residential solid energy, the evaluation of its health risks and environmental impacts is of necessity. Empirical studies on the characteristics of toxic emissions from biomass burning would provide scientific data and drive the development of advanced technologies. This review focuses on the emission of four toxic substances, including heavy metals, polycyclic aromatic hydrocarbons (PAHs), elemental carbon (EC), and volatile organic compounds (VOCs) emitted from biomass burning, which have received increasing attention in recent studies worldwide. We focus on the developments in empirical studies, methods of measurements, and technical factors. The influences of key technical factors on biomass burning emissions are combustion technology and the type of biomass. The methods of sampling and testing are summarized and associated with various corresponding parameters, as there are no standard sampling methods for the biomass burning sector. Integration of the findings from previous studies indicated that modern combustion technologies result in a 2–4 times reduction, compared with traditional stoves. Types of biomass burning are dominant contributors to certain toxic substances, which may help with the invention or implementation of targeted control technologies. The implications of previous studies would provide scientific evidence to push the improvements of control technologies and establish appropriate strategies to improve the prevention of health hazards.

Methylated polycyclic aromatic hydrocarbons from household coal use across the life course and risk of lung cancer in a large cohort of 42,420 subjects in Xuanwei, China

BACKGROUND

We previously showed that exposure to 5-methylchrysene (5MC) and other methylated polycyclic aromatic hydrocarbons (PAHs) best explains lung cancer risks in a case-control study among non-smoking women using smoky coal in China. Time-related factors (e.g., age at exposure) and non-linear relations were not explored.

OBJECTIVE

We investigated the relation between coal-derived air pollutants and lung cancer mortality using data from a large retrospective cohort.

METHODS

Participants were smoky (bituminous) or smokeless (anthracite) coal users from a cohort of 42,420 subjects from four communes in XuanWei. Follow-up was from 1976 to 2011, during which 4,827 deaths from lung-cancer occurred. Exposures were predicted for 43 different pollutants. Exposure clusters were identified using hierarchical clustering. Cox regression was used to estimate exposure-response relations for 5MC, while effect modification by age at exposure was investigated for cluster prototypes. A Bayesian penalized multi-pollutant model was fitted on a nested case-control sample, with more restricted models fitted to investigate non-linear exposure-response relations.

RESULTS

We confirmed the strong exposure-response relation for 5MC (Hazard Ratio [95% Confidence Interval] = 2.5 [2.4, 2.6] per standard-deviation (SD)). We identified four pollutant clusters, with all but two PAHs in a single cluster. Exposure to PAHs in the large cluster was associated with a higher lung cancer mortality rate (HR [95%CI] = 2.4 [2.2, 2.6] per SD), while exposure accrued before 18 years of age appeared more important than adulthood exposures. Results from the multi-pollutant model identified anthanthrene (ANT) and benzo(a)chrysene (BaC) as risk factors. 5MC remained strongly associated with lung cancer in models that included ANT and BaC and also benzo(a)pyrene (BaP).

CONCLUSION

We confirmed the link between PAH exposures and lung cancer in smoky coal users and found exposures before age 18 to be especially important. We found some evidence for the carcinogen 5MC and non-carcinogens ANT and BaC.

Overall and cause-specific mortality rates among men and women with high exposure to indoor air pollution from the use of smoky and smokeless coal: a cohort study in Xuanwei, China

OBJECTIVES

Never-smoking women in Xuanwei (XW), China, have some of the highest lung cancer rates in the country. This has been attributed to the combustion of smoky coal used for indoor cooking and heating. The aim of this study was to evaluate the spectrum of cause-specific mortality in this unique population, including among those who use smokeless coal, considered 'cleaner' coal in XW, as this has not been well-characterised.

DESIGN

Cohort study.

SETTING

XW, a rural region of China where residents routinely burn coal for indoor cooking and heating.

PARTICIPANTS

Age-adjusted, cause-specific mortality rates between 1976 and 2011 were calculated and compared among lifetime smoky and smokeless coal users in a cohort of 42 420 men and women from XW. Mortality rates for XW women were compared with those for a cohort of predominately never-smoking women in Shanghai.

RESULTS

Mortality in smoky coal users was driven by cancer (41%), with lung cancer accounting for 88% of cancer deaths. In contrast, cardiovascular disease (CVD) accounted for 32% of deaths among smokeless coal users, with 7% of deaths from cancer. Total cancer mortality was four times higher among smoky coal users relative to smokeless coal users, particularly for lung cancer (standardised rate ratio (SRR)=17.6). Smokeless coal users had higher mortality rates of CVD (SRR=2.9) and pneumonia (SRR=2.5) compared with smoky coal users. These patterns were similar in men and women, even though XW women rarely smoked cigarettes. Women in XW, regardless of coal type used, had over a threefold higher rate of overall mortality, and most cause-specific outcomes were elevated compared with women in Shanghai.

CONCLUSIONS

Cause-specific mortality burden differs in XW based on the lifetime use of different coal types. These observations provide evidence that eliminating all coal use for indoor cooking and heating is an important next step in improving public health particularly in developing countries.

Particle size-resolved emission characteristics of complex polycyclic aromatic hydrocarbon (PAH) mixtures from various combustion sources

Combustion of domestic solid fuels is a significant source of polycyclic aromatic hydrocarbons (PAHs). Some oxygenated PAHs (o-PAHs) and PAHs with molecular weight of 302 (MW302 PAHs) are more toxic than the traditional 16 priority PAHs, whereas their emissions were much less elucidated. This study characterized the size-dependent emissions of parent PAHs (p-PAHs), o-PAHs, and MW302 PAHs from various combustion sources. The estimated emission factors (eEFs) from biomass burning sources were highest for most of the PAHs (391-8928 μg/kg), much higher than that of anthracite coal combustion (43.0-145 μg/kg), both which were operated in an indoor stove. Cigarette smoking had a high eEF of o-PAHs (240 ng/g). MW302 PAHs were not found in the emissions of smoking, cooking, and vehicular exhausts. Particle-size distributions of PAHs were compound- and source-dependent, and the tendency to associate with smaller particles was observed especially in biomass burning and cigarette smoking sources. Furthermore, the inter-source differences in PAH eEFs were associated with their dominance in fine particles. PAH composition profiles also varied with the particle size, showing increasing contributions of large-molecule PAHs with decreasing sizes in most cases. The size distributions of p-PAHs are much more significantly dependent on their n-octanol/air partition coefficients and vapor pressures than those of o-PAHs, suggesting differences in mechanisms governing their distributions. Several molecular diagnostic ratios (MDRs), including two based on MW302 PAHs, specific to these combustion scenarios were identified. However, the MDRs within some sources are also strongly size-dependent, providing a new explanation for the uncertainty in their application for source identification of PAHs. This work also highlights the necessity for understanding the size-resolved atmospheric behaviors and fate of PAHs after their emission.

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.

Sociodemographic and clinical characteristics associated with never-smoking status in patients with lung cancer: findings from a large integrated health system

Background

Evidence is limited characterizing sociodemographically diverse patient populations with lung cancer in relation to smoking status.

Methods

In a cross-sectional analysis of adults diagnosed with lung cancer at ages ≥30 years from 2007-2018 within an integrated healthcare system, overall and sex-specific prevalence of never smoking were estimated according to sociodemographic and clinical characteristics. Adjusted prevalence ratio (aPR) and 95% confidence interval (CI) were also estimated using modified Poisson regression to identify patient characteristics associated with never smoking, overall and by sex. Similar analyses were conducted to explore whether prevalence and association patterns differed between non-Hispanic White and Asian/Pacific Islander patients.

Results

Among 17,939 patients with lung cancer, 2,780 (15.5%) never smoked and 8,698 (48.5%) had adenocarcinoma. Overall prevalence of never smoking was higher among females than males (21.2% vs. 9.2%, aPR 2.13, 95% CI: 1.98-2.29); Asian/Pacific Islander (aPR 2.85, 95% CI: 2.65-3.07) and Hispanic (aPR 1.72, 95% CI: 1.51-1.95) than non-Hispanic White patients; patients who primarily spoke Spanish (aPR 1.60, 95% CI: 1.32-1.94), any Asian language (aPR 1.20, 95% CI: 1.10-1.30), or other languages (aPR 1.84, 95% CI: 1.27-2.65) than English; patients living in the least vs. most deprived neighborhoods (aPR 1.36, 95% CI: 1.24-1.50); and patients with adenocarcinoma (aPR 2.57, 95% CI: 2.18-3.03), other non-small cell lung cancer (NSCLC) (aPR 2.00, 95% CI: 1.63-2.45), or carcinoid (aPR 3.60, 95% CI: 2.96-4.37) than squamous cell carcinoma tumors. Patterns of never smoking associated with sociodemographic, but not clinical factors, differed by sex. The higher prevalence of never smoking associated with Asian/Pacific Islander race/ethnicity was more evident among females (aPR 3.30, 95% CI: 2.95-3.47) than males (aPR 2.25, 95% CI: 1.92-2.63), whereas the higher prevalence of never smoking associated with living in the least deprived neighborhoods was more evident among males (aPR 1.93, 95% CI: 1.56-2.38) than females (aPR 1.18, 95% CI: 1.06-1.31). Associations between primary language and never-smoking status were found only among females. Overall and sex-specific prevalence and association patterns differed between Asian/Pacific Islander and non-Hispanic white patients.

Conclusions

Our findings suggest that patterns of never-smoking status associated with sociodemographic and clinical characteristics are different across sex and race/ethnicity among patients with lung cancer. Such data are critical to increasing awareness and expediting diagnosis of this disease.

Time series of transcriptome analysis in entire lung development stages provide insights into the origin of NO2 related lung diseases

Lung growth is a critical window, when exposure to various pollutants can disturb the finely-tuned lung development and enhance risk of long-term structural and functional sequelae of lung. In this study, pregnant C57/6 mice were treated with NO2, and lungs of fetus/offspring were collected at different developmental windows and dynamic lung development was determined. The results showed that maternal NO2 exposure suppressed fetal weight, implying that fetal development can be disturbed. The time-series RNA-seq analysis of lungs showed that maternal NO2 exposure induced significant time-dependent changes in the expression profiles of genes associated with lung vein myocardium development in fetus/offspring. Most of these genes in NO2 exposure group were suppressed at middle gestation and at birth. Our results also indicated that the gene expressions of Nkx2.5 in NO2 exposure were suppressed to 0.27- and 0.44-fold of the corresponding Air group at E13.5 and PND1, and restored at later time points. This indicated that the transcription factor Nkx2.5 played an important role in abnormal lung development in fetus/offspring caused by maternal NO2 exposure. Importantly, gene expressions of lung vein myocardium development were related to transcription factors (TFs) and lung functions, and TFs showed similar trends with lung function. These results provide a comprehensive view of the adverse effects of maternal NO2 exposure on fetal lung development by uncovering molecular targets and related signaling pathways at the transcriptional level.

Perception of worry of harm from air pollution: results from the Health Information National Trends Survey (HINTS)

Background

Air pollution exposure has been associated with a multitude of diseases and poses a significant concern to public health. For targeted environmental risk communication and interventions to be effective, it is important to correctly identify characteristics associated with worry of harm from air pollution.

Methods

Using responses from 3,630 participants of the Health Information National Trends Survey 4 Cycle 2, we assessed worry of harm from exposure to indoor (IAP) and outdoor (OAP) air pollution separately. Multinomial logistic regression models were used to calculate odds ratios and 95% confidence intervals.

Results

Hispanics were more likely to worry about harm from IAP and OAP compared to non-Hispanic whites. Participants who lived in metropolitan counties were more likely to worry about harm from IAP and OAP compared to those who lived in rural counties. Finally, those who believed their chance of getting cancer was high were more likely to worry about harm from IAP and OAP compared to those who thought their likelihood of getting cancer was low.

Conclusions

Worry of harm from IAP and OAP varied across sociodemographic and cancer-related characteristics. Public health professionals should consider these characteristics when developing targeted environmental risk communication and interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13450-z.

Large contribution of non-priority PAHs in atmospheric fine particles: Insights from time-resolved measurement and nontarget analysis

Polycyclic aromatic hydrocarbons (PAHs), detrimental to human health, are key components contributing to the carcinogenicity of fine particles. The 16 priority PAHs listed by the United States Environment Protection Agency have been studied extensively. However, other than them, there is a large diversity of PAH species, whose atmospheric concentrations, risks, and variations remain elusive. Here, we carried out a time-resolved nontarget measurement in atmospheric PM_2.5 using an improved comprehensive two-dimensional gas chromatography mass spectrometry. The measurement conducted during a 5-day pollution episode at an urban site of Beijing with a time resolution of 2 h. The nontarget analysis of time-resolved chromatographic data was performed for screening PAHs. A total number of 85 PAHs were identified and quantified. We found that other than 16 EPA PAHs, other screened PAHs contributed 43.3% of the total PAH mass concentration and 40.8% poential health risks. Dynamic variations of mass concentrations and their potential health risks of the screened PAHs were captured during a short-term heavy pollution episode, during which the instantaneous PAHs concentrations were much higher than their average concentrations. This study shows the potential for application of nontarget analysis for online comprehensive two-dimensional gas chromatography mass spectrometry and highlights the importance of time-resolved measurement of PAHs in PM_2.5 and attention on extended PAHs species other than 16 EPA PAHs.

Long-term environmental surveillance of PM2.5-bound polycyclic aromatic hydrocarbons in Jinan, China (2014-2020): Health risk assessment

We established long-term surveillance sites in Jinan city to monitor PM_2.5 particles (PM2.5) and PM2.5-bound PAHs (2014-2020). The range of PM2.5 was 15-230 µg/m³. The average annual ƩPAH₁₆ were 433 ± 271 ng/m³ (industrial area) and 299 ± 171.8 ng/m³ (downtown). PAHs captured in winter accounted for 61.5% (industrial area) and 59.1% (downtown) of total PAHs. A hazardous seasonal benzo[a]pyrene level was detected in 2015-2016 winter as 14.03 ng/m³ (14 folds of EU standard). The dominant PM2.5-bound PAHs were benzo[b]fluoranthene (24-26%), chrysene (19-20%), benzo[g,h,i]perylene (15%), Indeno(1,2,3-cd)pyrene (12%) and Benzo[a]pyrene (10%). Toxic equivalent quotients of PAHs were 4.93 ng/m³ (industrial area) and 3.13 ng/m³ (downtown). Excess cancer risks (ECRs) were 4.3 × 10^-4 ng/m³ and 2.7 × 10^-4 ng/m³, respectively. The ECRs exceeded EPA regulatory limit of 1 × 10^-6 ng/m³ largely. Non-negligible excess lifetime cancer risks were found as 36 and 26 related cancer incidences per 1,000,000 people. Consistently, local prevalence of lung cancer raise from 56.97/100,000 to 72.38/100,000; the prevalence of thyroid cancer raise from 10.12/100,000 to 45.26/100,000 from 2014 to 2020. Our findings suggest an urgent need to investigate the adverse health effects of PAHs on local population and we call for more strictly restriction on coal consumption and traffic tail gas emission.

Burden of lung cancer attributable to household air pollution in the Chinese female population: trend analysis from 1990 to 2019 and future predictions

This study analyzes the long-term trend of the burden of lung cancer attributable to household air pollution in the Chinese female population, from 1990 to 2019, and make predictions for the next decade. Based the data from the 2019 Global Burden of Diseases (GBD 2019), the joinpoint regression model was used to reflect the temporal trend of the burden of lung cancer attributable to household air pollution, and an autoregressive integrated moving average (ARIMA) model was used to predict the burden of disease over the next decade. From 1990 to 2019, the age-standardized mortality and disability-adjusted life years (DALYs) rates of the Chinese female population were higher than the global rates, and the gap due to residential radon increased over time. The burden of lung cancer attributable to solid fuels has shown a significant downward trend while that due to residential radon has increased slightly overall, but remains lower than the former. The burden of lung cancer increased with age, and the peak age of DALYs rates changed from 70 < 75 years in 1990 to 75 < 80 years in 2019. The model predicted that the burden of lung cancer attributable to solid fuels will gradually decrease over the next decade, whereas the burden of lung cancer due to residential radon will gradually increase and surpass the burden due to solid fuels in 2023. Residential radon will become a more important factor of household air pollution than solid fuels in the next decade for the Chinese female population. Future interventions targeted at household air pollution are needed to reduce the burden of lung cancer.

Associations of polycyclic aromatic hydrocarbons exposure and its interaction with XRCC1 genetic polymorphism with lung cancer: A case-control study

Humans are extensively exposed to polycyclic aromatic hydrocarbons (PAHs) daily via multiple pathways. Epidemiological studies have demonstrated that occupational exposure to PAHs increases the risk of lung cancer, but related studies in the general population are limited. Hence, we conducted a case-control study among the Chinese general population to investigate the associations between PAHs exposure and lung cancer risk and analyze the modifications of genetic polymorphisms in DNA repair genes. In this study, we enrolled 122 lung cancer cases and 244 healthy controls in Wuhan, China. Urinary PAHs metabolites were determined by gas chromatography-mass spectrometry, and rs25487 in X-ray repair cross-complementation 1 (XRCC1) gene was genotyped by the Agena Bioscience MassARRAY System. Then, multivariable logistic regression models were performed to estimate the potential associations. We found that urinary hydroxynaphthalene (OH-Nap), hydroxyphenanthrene (OH-Phe) and the sum of hydroxy PAHs (∑OH-PAHs) levels were significantly higher in lung cancer cases than those in controls. After adjusting for gender, age, BMI, smoking status, smoking pack-years, drinking status and family history, urinary ∑OH-Nap and ∑OH-Phe levels were positively associated with lung cancer risk, with dose-response relationships. Compared with those in the lowest tertiles, individuals in the highest tertiles of ∑OH-Nap and ∑OH-Phe had a 2.13-fold (95% CI: 1.10, 4.09) and 2.45-fold (95% CI: 1.23, 4.87) increased risk of lung cancer, respectively. Effects of gender, age, smoking status and smoking pack-years on the associations of PAHs exposure with lung cancer risk were shown in the subgroup analysis. Furthermore, associations of urinary ∑OH-Nap and ∑OH-PAHs levels with lung cancer risk were modified by XRCC1 rs25487 (P_interaction ≤ 0.025), and were more pronounced in wild-types of rs25487. These findings suggest that environmental exposure to naphthalene and phenanthrene is associated with increased lung cancer risk, and polymorphism of XRCC1 rs25487 might modify the naphthalene exposure-related lung cancer effect.

Comparison of naphthalene removal performance using H2O2, sodium percarbonate and calcium peroxide oxidants activated by ferrous ions and degradation mechanism

The presence of polycyclic aromatic hydrocarbons (PAHs) in groundwater is making a great threat to human health in the world which has received an increasing environmental concern. Among various Fenton oxidation processes, 97.6%, 92.1% and 89.4% naphthalene (NaP) removals were observed using hydrogen peroxide (H₂O₂), sodium percarbonate (SPC) and calcium peroxide (CP) as oxidants activated by Fe(II) in ultrapure water tests, respectively. While, the inhibitory effect on NaP degradation caused by the weak alkaline solution pH and the presence of HCO₃^- in actual groundwater could be compensated by doubling dosages of oxidants and Fe(II) to different extent. 98.0%, 49.8% and 11.5% of NaP were degraded by using H₂O₂, SPC and CP, respectively, strongly suggesting the best H₂O₂ performance among them. It was observed that 83.3% and 9.6% inhibition on NaP degradation in H₂O₂/Fe(II)/NaP system occurred in the presence of isopropyl alcohol and chloroform, confirming that both hydroxyl radical (HO) and superoxide anion radical () contributed to NaP degradation in Fenton process and HO was the prominent radical. The presence of HO was further demonstrated by electro-spin resonance spectrometer analysis. The identification of transformation products of NaP revealed that hydroxylation and ring rupture were the main NaP degradation pathways.

Elevated urinary mutagenicity among those exposed to bituminous coal combustion emissions or diesel engine exhaust

Urinary mutagenicity reflects systemic exposure to complex mixtures of genotoxic/carcinogenic agents and is linked to tumor development. Coal combustion emissions (CCE) and diesel engine exhaust (DEE) are associated with cancers of the lung and other sites, but their influence on urinary mutagenicity is unclear. We investigated associations between exposure to CCE or DEE and urinary mutagenicity. In two separate cross-sectional studies of nonsmokers, organic extracts of urine were evaluated for mutagenicity levels using strain YG1041 in the Salmonella (Ames) mutagenicity assay. First, we compared levels among 10 female bituminous (smoky) coal users from Laibin, Xuanwei, China, and 10 female anthracite (smokeless) coal users. We estimated exposure-response relationships using indoor air concentrations of two carcinogens in CCE relevant to lung cancer, 5-methylchrysene (5MC), and benzo[a]pyrene (B[a]P). Second, we compared levels among 20 highly exposed male diesel factory workers and 15 unexposed male controls; we evaluated exposure-response relationships using elemental carbon (EC) as a DEE-surrogate. Age-adjusted linear regression was used to estimate associations. Laibin smoky coal users had significantly higher average urinary mutagenicity levels compared to smokeless coal users (28.4 ± 14.0 SD vs. 0.9 ± 2.8 SD rev/ml-eq, p = 2 × 10-5 ) and a significant exposure-response relationship with 5MC (p = 7 × 10-4 ). DEE-exposed workers had significantly higher urinary mutagenicity levels compared to unexposed controls (13.0 ± 10.1 SD vs. 5.6 ± 4.4 SD rev/ml-eq, p = .02) and a significant exposure-response relationship with EC (p-trend = 2 × 10-3 ). Exposure to CCE and DEE is associated with urinary mutagenicity, suggesting systemic exposure to mutagens, potentially contributing to cancer risk and development at various sites.

Tracing Lung Cancer Risk Factors Through Mutational Signatures in Never-Smokers

Epidemiologic studies often rely on questionnaire data, exposure measurement tools, and/or biomarkers to identify risk factors and the underlying carcinogenic processes. An emerging and promising complementary approach to investigate cancer etiology is the study of somatic "mutational signatures" that endogenous and exogenous processes imprint on the cellular genome. These signatures can be identified from a complex web of somatic mutations thanks to advances in DNA sequencing technology and analytical algorithms. This approach is at the core of the Sherlock-Lung study (2018-ongoing), a retrospective case-only study of over 2,000 lung cancers in never-smokers (LCINS), using different patterns of mutations observed within LCINS tumors to trace back possible exposures or endogenous processes. Whole genome and transcriptome sequencing, genome-wide methylation, microbiome, and other analyses are integrated with data from histological and radiological imaging, lifestyle, demographic characteristics, environmental and occupational exposures, and medical records to classify LCINS into subtypes that could reveal distinct risk factors. To date, we have received samples and data from 1,370 LCINS cases from 17 study sites worldwide and whole-genome sequencing has been completed on 1,257 samples. Here, we present the Sherlock-Lung study design and analytical strategy, also illustrating some empirical challenges and the potential for this approach in future epidemiologic studies.

Pemetrexed-Platinum With or Without Bevacizumab for Chinese Chemo-Naive Advanced Lung Adenocarcinoma Patients: A Real-World Study

Despite recent advances in the treatment of advanced non-small-cell lung cancer (NSCLC), bevacizumab plus platinum-based doublet chemotherapy remains a commonly used first-line regimen. This study was conducted to compare the efficacy and safety of pemetrexed-platinum with or without bevacizumab in Chinese chemo-naive advanced lung adenocarcinoma patients in a real-world setting. We retrospectively collected 100 patients who received pemetrexed-platinum with or without bevacizumab (PP, n = 46; Bev+PP, n = 54) until disease progression or unacceptable toxicity. Clinical characteristics of patients were balanced, except for the proportion of stage IV b+c (Bev+PP and PP: 67.4 vs. 37.0%, p = 0.0066). Bev+PP significantly improved the objective response rate (ORR, 65 vs. 30%, p = 0.0004) and progression-free survival (PFS, 7.4 vs. 6.8 months, p = 0.009), but not overall survival (OS, 17.5 vs. 15.0 months, p = 0.553) compared with PP. Treatment (p = 0.001), gender (p = 0.008), adrenal metastasis (p = 0.001), and liver metastasis (p = 0.013) were independent risk factors for PFS. Patients with adrenal metastasis tended to be at the highest risk of not benefiting from bevacizumab addition (HR [95% CI]: 2.244 [0.6495-7.753]). The safety profile was acceptable, and grade ≥3 toxicity occurred similarly. This study showed that pemetrexed-platinum plus bevacizumab was effective compared to chemotherapy alone in Chinese patients with advanced NSCLC.

Concentrations of selected monohydroxy polycyclic aromatic hydrocarbons across various stages of glomerular function

The objective of this study was to evaluate the variabilities in the concentrations of selected monohydroxy polycyclic aromatic hydrocarbons (OH-PAH) in urine across various stages of glomerular function. Data from National Health and Nutrition Examination Survey for US adult smokers (N = 3125) and nonsmokers (N = 6793) were selected for analysis to meet the objectives of the study. OH-PAHs selected for analysis were as follows: 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 3-hydroxyfluorene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 1-hydroxypyrene. Stages of glomerular function (GF) considered were as follows: hyperfiltrators (GF-1A, eGFR ≥ 110 mL/min/1.73 m²), normal filtrators (GF-1B, 90 < eGFR < 110 mL/min/1.73 m²), GF-2 (60 ≤ eGFR < 90 mL/min/1.73 m²), GF-3A (45 ≤ eGFR < 60 mL/min/1.73 m²), and GF-3B/4 (15 ≤ eGFR < 45 mL/min/1.73 m²). For the analysis of data for smokers, however, data for GF-3A and GF-3B/4 were merged because of small sample sizes for these GF stages for smokers. Among nonsmokers, (i) there was almost a straight-line decrease in adjusted concentrations of 2-hydroxyfluorene, 3-hydroxyfluorene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 1-hydroxypyrene over GF-1A through GF-3B/4; (ii) concentrations of these OH-PAHs at GF-3B/4 varied from being 37.5% for 1-hydroxypyrene to being 87% for 9-hydroxyfluorene of what they were at GF-1A; and (iii) while concentrations of 1-hydroxynaphthalene were located on an inverted U-shaped curve, concentrations of 2-hydroxynaphthalene were located on a U-shaped curve with pints of inflections at GF-3A. Among smokers, concentrations of all nine OH-PAHs in urine were located on inverted U-shaped curves with points of inflections located at GF-2 and concentrations of these OH-PAHs at GF-3/4 varied from being 48.7% for 1-hydroxypyrene to being 116.1% for 9-hydroxyfluorene of what they were at GF-1A. The kidneys differ in how they process urinary metabolites of PAHs among smokers and nonsmokers.

Multiple air pollutant exposure and lung cancer in Tehran, Iran

Lung cancer is the most rapidly increasing malignancy worldwide with an estimated 2.1 million cancer cases in the latest, 2018 World Health Organization (WHO) report. The objective of this study was to investigate the association of air pollution and lung cancer, in Tehran, Iran. Residential area information of the latest registered lung cancer cases that were diagnosed between 2014 and 2016 (N = 1,850) were inquired from the population-based cancer registry of Tehran. Long-term average exposure to PM₁₀, SO₂, NO, NO₂, NO_X, benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene (BTEX), and BTEX in 22 districts of Tehran were estimated using land use regression models. Latent profile analysis (LPA) was used to generate multi-pollutant exposure profiles. Negative binomial regression analysis was used to examine the association between air pollutants and lung cancer incidence. The districts with higher concentrations for all pollutants were mostly in downtown and around the railway station. Districts with a higher concentration for NOx (IRR = 1.05, for each 10 unit increase in air pollutant), benzene (IRR = 3.86), toluene (IRR = 1.50), ethylbenzene (IRR = 5.16), p-xylene (IRR = 9.41), o-xylene (IRR = 7.93), m-xylene (IRR = 2.63) and TBTEX (IRR = 1.21) were significantly associated with higher lung cancer incidence. Districts with a higher multiple air-pollution profile were also associated with more lung cancer incidence (IRR = 1.01). Our study shows a positive association between air pollution and lung cancer incidence. This association was stronger for, respectively, p-xylene, o-xylene, ethylbenzene, benzene, m-xylene and toluene.

Regional Policies Targeting Residential Solid Fuel and Agricultural Emissions Can Improve Air Quality and Public Health in the Greater Bay Area and Across China

Air pollution exposure is a leading public health problem in China. The majority of the total air pollution disease burden is from fine particulate matter (PM2.5) exposure, with smaller contributions from ozone (O3) exposure. Recent emission reductions have reduced PM2.5 exposure. However, levels of exposure and the associated risk remain high, some pollutant emissions have increased, and some sectors lack effective emission control measures. We quantified the potential impacts of relevant policy scenarios on ambient air quality and public health across China. We show that PM2.5 exposure inside the Greater Bay Area (GBA) is strongly controlled by emissions outside the GBA. We find that reductions in residential solid fuel use and agricultural fertilizer emissions result in the greatest reductions in PM2.5 exposure and the largest health benefits. A 50% transition from residential solid fuel use to liquefied petroleum gas outside the GBA reduced PM2.5 exposure by 15% in China and 3% within the GBA, and avoided 191,400 premature deaths each year across China. Reducing agricultural fertilizer emissions of ammonia by 30% outside the GBA reduced PM2.5 exposure by 4% in China and 3% in the GBA, avoiding 56,500 annual premature deaths across China. Our simulations suggest that reducing residential solid fuel or industrial emissions will reduce both PM2.5 and O3 exposure, whereas other policies may increase O3 exposure. Improving particulate air quality inside the GBA will require consideration of residential solid fuel and agricultural sectors, which currently lack targeted policies, and regional cooperation both inside and outside the GBA.

Urinary carboxylic acid metabolites as possible novel biomarkers of exposures to alkylated polycyclic aromatic hydrocarbons

Previous studies have found that alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) were more abundant in petrogenic sources (e.g., crude oil and its refined products) than pyrogenic sources of incomplete combustion. While urinary hydroxylated metabolites of unsubstituted PAHs have been widely used as biomarkers of PAHs exposures, little information is available as to the occurrence of alkyl-PAH metabolites. In this study, we have detected carboxylic acid metabolites of alkyl-naphthalene (2-NAPCA) and alkyl-phenanthrene (2-PHECA) in 314 urine samples repeatedly collected from 45 Los Angeles residents before, during, and after they spent ten weeks in Beijing in summers of 2014-2017. We found that traveling from Los Angeles to Beijing led to 348% (95% CI: 243 to 485%) and 209% (95% CI: 149 to 282%) increases in 2-NAPCA and 2-PHECA concentrations, respectively, which returned to baseline levels after participants came back to Los Angeles. The concentration ratio between 2-PHECA and hydroxy-phenanthrenes was significantly (p < 0.05) lower in Beijing (median: 0.40, IQR: 0.27-0.53) than in Los Angeles (median: 0.51, IQR: 0.32-0.77), where more than 5,000 active gas and oil wells were located. From 2014 to 2017, the concentration ratio of 2-PHECA to hydroxy-phenanthrenes increased by 28.7 (95%CI: 12.3 to 47.6) %/yr in Los Angeles and 18.6 (95%CI: 7.9 to 30.3) %/yr in Beijing, likely resulted from both cities' efforts to reduce pyrogenic emissions (e.g. vehicle exhaust). These results provided indirect evidence supporting the use of 2-PHECA to hydroxy-phenanthrene ratio as an index to reflect the relative exposure contributions from petrogenic and pyrogenic sources. While our study suggested that urinary PAHCAs may be novel biomarkers of exposure to alkyl-PAHs, future studies with external exposure characterization are warranted to further validate these biomarkers.

Transcriptome Sequencing reveals the expressed profiles of mRNA and ncRNAs and regulate network via ceRNA mediated molecular mechanism of lung adenocarcinoma bone metastasis in Xuanwei

Background

The most ordinary subtype of lung cancer is lung adenocarcinoma (LuAC), which is characterized by strong metastatic ability. And LuAC rates in Xuanwei leads to the poor prognosis and high death rate. In this study, we systematically explored the molecular mechanism of LuAC bone metastasis in Xuanwei by transcriptome sequencing.

Methods

RNA Sequencing was conducted to explore the noncoding RNAs (ncRNAs) expression profiles in primary LuAC and LuAC bone metastasis. We identified differentially expressed mRNAs (DEmRNAs), miRNAs (DEmiRNAs), lncRNAs (DElncRNAs) and circRNAs (DEcircRNAs). Bioinformatics analyses the possible relationships and functions of the LuAC bone metastasis-related competing endogenous RNA (ceRNA). And qRT-PCR was performed to evaluate the expression of these differently expressed genes in serum.

Results

A total of 2,141 DEmRNAs, 43 DEmiRNAs, 136 DElncRNAs and 706 DEcircRNAs were identified in the Xuanwei patients with primary LuAC vs. LuAC bone metastasis, respectively. The circRNA/miRNA/mRNA and lncRNA/miRNA/mRNA networks of LuAC in Xuanwei with bone metastasis were built, and the gene expression mechanisms regulated by ncRNAs were unveiled via the ceRNA regulatory networks. We observe that lncRNA (ADAMTS9-AS2, TEX41, DLEU2, LINC00152)-miR-223-3p-SCARB1 and hsa_circ_0000053-miR-196a-5p/miR-196b-5p-HOXA5 ceRNA networks might play an important role in bone metastasis of Xuanwei LuAC.

Conclusions

We comprehensively identified ceRNA regulatory networks of LuAC in Xuanwei with bone metastasis as well as revealed the contribution of different ncRNAs expression profiles. Our data demonstrate the association between mRNAs and ncRNAs in the metastasis mechanism of LuAC in Xuanwei with bone metastasis.

Effects and mechanism of microRNA‑218 against lung cancer

Lung cancer is the most prevalent and observed type of cancer in Xuanwei County, Yunnan, South China. Lung cancer in this area is called Xuanwei lung cancer. However, its pathogenesis remains largely unknown. To date, a number of studies have shown that microRNA (miR)‑218 functions as a tumor suppressor in multiple types of cancer. However, the role of miR‑218 and its regulatory gene network in Xuanwei lung cancer have yet to be investigated. The current study identified that the expression levels of miR‑218 in XWLC‑05 cells were markedly lower compared with those in immortalized lung epithelial BEAS‑2B cells. The present study also demonstrated that overexpression of miR‑218 could decrease cell proliferation, invasion, viability and migration in Xuanwei lung cancer cell line XWLC‑05 and NSCLC cell line NCI‑H157. Additionally, the results revealed that overexpression of miR‑218 could induce XWLC‑05 and NCI‑H157 cell apoptosis by arresting the cell cycle at G2/M phase. Finally, the present study demonstrated that overexpression of miR‑218 could lead to a significant increase in phosphatase and tensin homolog (<em>PTEN</em>) and YY1 transcription factor (<em>YY1</em>), and a decrease in B‑cell lymphoma 2 (<em>BCL‑2</em>) and BMI1 proto‑oncogene, polycomb ring finger (<em>BMI‑1</em>) at the mRNA and protein level in XWLC‑05 and NCI‑H157 cell lines. However, we did not observe any remarkable difference in the roles of miR‑218 and miR‑218‑mediated regulation of <em>BCL‑2</em>, <em>BMI‑1</em>, <em>PTEN</em> and <em>YY1</em> expression in the progression of Xuanwei lung cancer. In conclusion, miR‑218 could simultaneously suppress cell proliferation and tumor invasiveness and induce cell apoptosis by increasing <em>PTEN</em> and <em>YY1</em> expression, while decreasing <em>BCL‑2</em> and <em>BMI‑1</em> in Xuanwei lung cancer. The results demonstrated that miR‑218 might serve a vital role in tumorigenesis and progression of Xuanwei lung cancer and overexpression of miR‑218 may be a novel approach for the treatment of Xuanwei lung cancer.

Development and validation of the cancer symptoms discrimination scale: a cross-sectional survey of students in Yunnan, China

Background

This study aimed to devise a Cancer symptoms Discrimination Scale (CSDS) suitable for China based on a cross-sectional survey.

Methods

The CSDS was developed using the classical measurement theory. A total of 3610 students from Yunnan province, China, participated in the cross-sectional survey. The test version of the scale was modified by the item analysis method, and after the official version of CSDS was developed, its reliability and validity were verified. A univariate analysis of variance and a multiple linear regression model were used to analyze the influencing factors of cancer symptoms discrimination among the university/college students.

Results

There were 21 items in total for the CSDS, including 3 subscales --- common clinical manifestations (11 items), physical appearance defects (6 items), and drainage tube(s) wearing (4 items). This CSDS had good validity (GFI = 0.930, AGFI = 0.905, RMR = 0.013, I-CVIs> 0.80, and the Pearson correlation coefficient was satisfactory.) and reliability (Cronbach’s alpha = 0.862, spearman-brown coefficient = 0.875). The multiple linear regression showed that certain factors may affect the students’ discrimination level against cancer symptoms (P < 0.05), including gender, major, current education degree, guardian’s highest record of formal schooling, self-rated health status, history of care for cancer patients, family relationship, ways of cancer knowledge acquisition, good/poor understanding of cancer-related information, degree of cancer fear, and their perception of cancer infectiousness.

Conclusion

This CSDS, with good reliability and validity, can be used for the evaluation of the discrimination risk and levels against cancer symptoms among healthy students.

Magnitude, temporal trends and inequality in global burden of tracheal, bronchus and lung cancer: findings from the Global Burden of Disease Study 2017

Introduction

We aimed to assess the magnitude, temporal trends and socioeconomic disparity in the global burden of tracheal, bronchus and lung (TBL) from 1990 to 2017, using data extracted from the Global Burden of Diseases study (GBD 2017).

Methods

We extracted data from the GBD 2017 study. A series of comparative and descriptive analyses of the disease burden between females and males and countries with different socioeconomic development statuses (Social Demographic Index, SDI). We also analysed the temporal trends of age-standardised disability-adjusted life year rates (ASDR) of TBL cancer at the global and super-regional level by means of joinpoint regression. Finally, we also calculated Concentration Index to explore trends of between-country inequality in cancer burden from 1990 to 2017.

Results

During the past 27 years, the global incidence of TBL cancer cases and death cases has increased by 100% and 82.3% respectively, but the increase number was mainly influenced by population growth and ageing. After adjustment, from 1990 to 2017, the ASDR of TBL has increased by 3% and the age-standardised death rate has decreased by 7%. The global TBL cancer burden fell by 15.3%. The joinpoint analysis revealed that the overall trend of age-standardised TBL cancer burden for both females and males significantly changed twice between 1990 and 2017, and it varied across countries with different SDI values and was also different between females and males. Age-standardised TBL cancer burden was more concentrated in higher socioeconomic development countries, but the development of healthy inequality showed a downward trend in males while showing an upward trend in females.

Conclusion

The magnitude and temporal trends of TBL cancer burden varied across countries and sex. This study highlighted the importance of crafting health policy to adapt to local conditions to manage the global burden of TBL cancers.

Association Between Outdoor Air Pollution and Risk of Malignant and Benign Brain Tumors: The Multiethnic Cohort Study

Background

There are increasing concerns about the potential impact of air pollution on chronic brain inflammation and microglia cell activation, but evidence of its carcinogenic effects is limited.

Methods

We used kriging interpolation and land use regression models to estimate long-term air pollutant exposures of oxides of nitrogen (NO_x, NO₂), kriging interpolation for ozone (O₃), carbon monoxide, and particulate matter (PM_2.5, PM₁₀), and nearest monitoring station measurements for benzene for 103 308 men and women from the Multiethnic Cohort, residing largely in Los Angeles County from recruitment (1993–1996) through 2013. We used Cox proportional hazards models to examine the associations between time-varying pollutants and risk of malignant brain cancer (94 men, 116 women) and meningioma (130 men, 425 women) with adjustment for sex, race and ethnicity, neighborhood socioeconomic status, smoking, occupation, and other covariates. Stratified analyses were conducted by sex and race and ethnicity.

Results

Brain cancer risk in men increased in association with exposure to benzene (hazard ratio [HR] = 3.52, 95% confidence interval [CI] = 1.55 to 7.55) and PM₁₀ (HR = 1.80, 95% CI = 1.00 to 3.23). Stronger associations with PM₁₀ (HR = 3.02, 95% CI = 1.26 to 7.23), O₃ (HR = 2.93, 95% CI = 1.09 to 7.88), and benzene (HR = 4.06, 95% CI = 1.17 to 18.2) were observed among Latino men. Air pollution was unrelated to risk of meningioma except that O₃ exposure was associated with risk in men (HR = 1.77, 95% CI = 1.02 to 3.06). Brain cancer risk in women was unrelated to air pollution exposures.

Conclusions

Confirmation of these sex differences in air pollution–brain cancer associations and the stronger findings in Latino men in additional diverse populations is warranted.