Asthma and risk of death from lung cancer: NHANES II Mortality Study

Association between asthma, chronic bronchitis, emphysema, chronic obstructive pulmonary disease, and lung cancer in the US population

Lung cancer is one of the primary causes of death with poor life expectancy after diagnosis. History of past respiratory diseases such as asthma, chronic obstructive lung disease (COPD), emphysema, and chronic bronchitis can increase the risk of lung cancer. Very few studies are available to simultaneously assess multiple respiratory diseases and lung cancer. The objective of this study was to investigate correlations between asthma, emphysema, chronic bronchitis, and chronic obstructive lung disease with lung cancer in the US adult population. This was a cross-sectional study using data from a total of 23,523 adult participants from the National Health Examination and Nutrition Survey (NHANES) datasets for seven cycles ranging from 2003-2004 to 2015-2016. To analyze the data, specialized weighted complex survey logit regressions were conducted. Linear logit regression models using only main-effects were constructed first to assess the correlation between the selected demographic and lifestyle variables and asthma, emphysema, chronic bronchitis, and COPD. A second set of linear, main-effects logit regression models were constructed to examine the correlation between lung cancer and asthma, emphysema, chronic bronchitis, COPD when corrected for the selected covariates. The study identified positive correlations between emphysema, chronic bronchitis, COPD, and lung cancer. No correlation between asthma and lung cancer was established. Of the covariates studied, race/ethnicity, marital status, highest educational level, age, family income to poverty ratio, and lifetime smoking were also found to be correlated with the presence of lung cancer. Correlations between the covariates gender, body mass index, alcohol consumption, and country of birth and lung cancer were not found. The study established statistically significant correlations between lung cancer and the lung diseases emphysema, chronic bronchitis, and COPD. The lack of association between asthma and lung cancer may arise from the timeline of diagnosis asthma or type of lung cancer. The study also established significant correlations between lung cancer and several of the covariates included in the analysis. It also established correlations between the covariates and the lung diseases asthma, emphysema, chronic bronchitis, and COPD.

Long-term exposure to house dust mites accelerates lung cancer development in mice

BACKGROUND

Individuals with certain chronic inflammatory lung diseases have a higher risk of developing lung cancer (LC). However, the underlying mechanisms remain largely unknown. Here, we hypothesized that chronic exposure to house dust mites (HDM), a common indoor aeroallergen associated with the development of asthma, accelerates LC development through the induction of chronic lung inflammation (CLI).  METHODS: The effects of HDM and heat-inactivated HDM (HI-HDM) extracts were evaluated in two preclinical mouse models of LC (a chemically-induced model using the carcinogen urethane and a genetically-driven model with oncogenic KrasG12D activation in lung epithelial cells) and on murine macrophages in vitro. Pharmacological blockade or genetic deletion of the Nod-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome, caspase-1, interleukin-1β (IL-1β), and C-C motif chemokine ligand 2 (CCL2) or treatment with an inhaled corticosteroid (ICS) was used to uncover the pro-tumorigenic effect of HDM.  RESULTS: Chronic intranasal (i.n) instillation of HDM accelerated LC development in the two mouse models. Mechanistically, HDM caused a particular subtype of CLI, in which the NLRP3/IL-1β signaling pathway is chronically activated in macrophages, and made the lung microenvironment conducive to tumor development. The tumor-promoting effect of HDM was significantly decreased by heat treatment of the HDM extract and was inhibited by NLRP3, IL-1β, and CCL2 neutralization, or ICS treatment.

CONCLUSIONS

Collectively, these data indicate that long-term exposure to HDM can accelerate lung tumorigenesis in susceptible hosts (e.g., mice and potentially humans exposed to lung carcinogens or genetically predisposed to develop LC).

Higher mortality of adults with asthma: A 15-year follow-up of a population-based cohort

BACKGROUND

Higher all-cause mortality in asthmatics has been shown previously. Polysensitization is associated with higher morbidity among asthmatic children, and allergic rhinitis and/or allergic conjunctivitis (AR/AC) are associated with higher morbidity in adult asthmatics. Little is known about the effect of AR/AC and other factors on mortality among adult asthmatics. The aim was to study mortality and its risk factors in adults with and without asthma.

METHODS

We randomly selected 1648 asthmatics with age over 30 years from national registers and matched the asthma sample with one or two controls. Baseline information was obtained by a questionnaire in 1997, and the study population was linked with the death certificate information of Statistics Finland from 1997 to 2013. Overall and cause-specific survival between the groups was compared in several adjusted models.

RESULTS

During a mean follow-up period of 15.6 years, 221 deaths among 1052 asthma patients and 335 deaths among 1889 nonasthmatics were observed. Cardiovascular diseases were the main cause of death in both groups. Asthma was associated with increased all-cause mortality (adjusted HR 1.25; 95% CI 1.05-1.49, P = .011) as well as mortality from chronic obstructive pulmonary disease (HR 12.0, 4.18-34.2, P < .001) and malignant neoplasms of respiratory organs (HR 2.33, 1.25-4.42, P = .008). Among asthmatics, smoking was associated with increased all-cause mortality, and self-reported AR/AC was associated with decreased mortality. Among nonasthmatics, smoking, and obesity were associated with increased all-cause mortality, whereas female gender showed an association with a decreased risk.

CONCLUSIONS

Increased mortality among adult asthmatics was largely explained by the development of COPD, malignant respiratory tract neoplasms, and cardiovascular diseases. Smoking cessation is important for reduction in total mortality in both asthmatic and nonasthmatic adults. AR/AC was associated with decreased mortality only in asthmatics. Thus, studies in other populations of larger size are needed to explore further the nature of this association.

Inflammatory Gene Polymorphisms in Lung Cancer Susceptibility

INTRODUCTION

Chronic inflammation has been implicated in carcinogenesis, with increasing evidence of its role in lung cancer. We aimed to evaluate the role of genetic polymorphisms in inflammation-related genes in the risk for development of lung cancer.

METHODS

A nested case-control study design was used, and 625 cases and 625 well-matched controls were selected from participants in the β-Carotene and Retinol Efficacy Trial, which is a large, prospective lung cancer chemoprevention trial. The association between lung cancer incidence and survival and 23 polymorphisms descriptive of 11 inflammation-related genes (interferon gamma gene [IFNG], interleukin 10 gene [IL10], interleukin 1 alpha gene [IL1A], interleukin 1 beta gene [IL1B], interleukin 2 gene [IL2], interleukin 4 receptor gene [IL4R], interleukin 4 gene [IL4], interleukin 6 gene [IL6], prostaglandin-endoperoxide synthase 2 gene [PTGS2] (also known as COX2), transforming growth factor beta 1 gene [TGFB1], and tumor necrosis factor alpha gene [TNFA]) was evaluated.

RESULTS

Of the 23 polymorphisms, two were associated with risk for lung cancer. Compared with individuals with the wild-type (CC) variant, individuals carrying the minor allele variants of the IL-1β-511C>T promoter polymorphism (rs16944) (CT and TT) had decreased odds of lung cancer (OR = 0.74, [95% confidence interval (CI): 0.58-0.94] and OR = 0.71 [95% CI: 0.50-1.01], respectively, p = 0.03). Similar results were observed for the IL-1β-1464 C>G promoter polymorphism (rs1143623), with presence of the minor variants CG and CC having decreased odds of lung cancer (OR = 0.75 [95% CI: 0.59-0.95] and OR = 0.69 [95% CI: 0.46-1.03], respectively, p = 0.03). Survival was not influenced by genotype.

CONCLUSIONS

This study provides further evidence that IL1B promoter polymorphisms may modulate the risk for development of lung cancer.

Inhaled corticosteroids may prevent lung cancer in asthma patients

BACKGROUND

It is unclear whether inhaled corticosteroids (ICS) have chemopreventive effect on lung cancer (LC) development in humans. We investigated the association between the ICS use in asthma patients and the risk of LC.

METHODS

We conducted a nationwide, population-based retrospective cohort study using the National Health Insurance database. We identified 4210 asthmatics who were initially free of LC and regularly used ICS between 2001 and 2005 and 37,228 asthmatics without regular ICS use. Patients with documented history of tobacco use were excluded from the analyses. Asthmatics were categorized into a mild and a severe asthma group. Each patient was tracked until the end of 2010 to identify incident cases of LC. Cox proportional hazards models were used to evaluate the effect of ICS on the risk of LC, further stratifying by asthma severity and comorbidities.

RESULTS

During follow-up, we identified 747 incident cases of LC diagnosed in the asthma cohort. Compared with severe asthmatics without regular ICS use, the risk of LC for those with mild asthma with regular ICS use was lower (adjusted hazard ratio = 0.42, 95% confidence interval = 0.31-0.56, P < 0.0001). The risk of LC was calculated among the following rankings of risk severe asthma without regular ICS use, low severity without regular ICS, high severity with regular ICS, and low severity with regular ICS group showed a decreasing trend of LC incidence (P = 0.041). Analyses stratified by comorbidities revealed that the protective effect of ICS was assessed with better precision and more pronounced in those with renal diseases, stroke, and hyperlipidemia.

CONCLUSIONS

For patients with asthma, regular ICS use might have a protective effect against LC. Further studies are required to assess this potential association from both immunohistopathological and clinical aspects.

Effect of pre existing respiratory conditions on survival of lung cancer patients: A nationwide population-based cohort study

BACKGROUND

Common diseases with potential to increase the risk of death from lung cancer have so far not been studied in large populations.

METHODS

We did a population-based retrospective cohort study using nationwide health insurance claims data from 2005 to 2012 in Korea including 205 403 lung cancer patients. Multivariate-adjusted hazard ratios (aHRs) of lung cancer mortality by presence, time intervals with lung cancer diagnosis and combinations of pre-existing chronic obstructive pulmonary disease (COPD), pneumonia, asthma and tuberculosis were calculated using the Cox-proportional hazards model.

RESULTS

The total number of person-years of follow-up was 397 780 and 60.2% of patients died (mean survival 23.2 months after lung cancer diagnosis). Lung cancer patients with previous respiratory disease had increased aHR for mortality (COPD, hazard ratio [HR] = 1.32, CI 1.29-1.35; pneumonia, HR = 1.14, CI 1.08-1.19; and asthma, HR = 1.11, CI 1.06-1.16). Risks were positively associated with longer duration of pre-existing disease diagnosis; cases with >5 years since diagnosis compared to <2 years: COPD, HR = 2.91, CI 2.82-3.00; pneumonia, HR = 1.67, CI 1.51-1.85; asthma, HR = 1.56, CI 1.45-1.68; and tuberculosis, HR = 2.03, CI 1.90-2.17. Furthermore, elevated HRs of death were found among patients with multiple pre-existing co-morbidities.

CONCLUSION

Hazards of death from lung cancer are significantly increased in cases with pre-existing lung disease, and worse with longer durations, and with multiple combinations before cancer diagnosis. Patients and physicians should be aware of these meaningful risk/prognostic factors for lung cancer when identifying high-risk patient groups.

Investigating the association between allergen-specific immunoglobulin E, cancer risk and survival

Prior findings linking allergy and cancer have been inconsistent, which may be driven by diverse assessment methods. We used serum specific immunoglobulin E (IgE) against common inhalant allergens that was assessed prior to cancer diagnosis in studying this association. We selected 8,727 Swedish men and women who had measurements of serum allergen-specific IgE and total IgE between 1992 and 1996. Multivariable Cox regression using age as a timescale was performed to assess the associations of IgE sensitization, defined by any levels of serum specific IgE ≥35 kU/L, with risk of overall and specific cancers. A test for trend was performed by assigning scores derived from allergen-specific IgE levels at baseline as an ordinal scale. Kaplan-Meier curves and log-rank test were used to assess cancer survival by IgE sensitization status. During a mean follow-up of 16 year, 689 persons were diagnosed with cancer. We found an inverse association between IgE sensitization and cancer risk, with a hazard ratio (HR) of 0.83 and 95% confidence intervals (CI) of 0.70-0.99. A similar trend was seen with specific IgE scores overall (Ptrend = 0.007) and in women (Ptrend = 0.01). Although IgE sensitization was not associated with risk of common site-specific cancers, serum specific IgE scores were inversely associated with melanoma risk in men and women combined, and with risk of female breast and gynecological cancers combined. No association with survival was observed. The association between circulating IgE levels and incident cancer may point toward a role of T-helper 2 (TH2)-biased response in development of some cancers.

Pre-existing Pulmonary Diseases and Survival in Patients With Stage-dependent Lung Adenocarcinoma: A STROBE-compliant Article

Asthma, chronic obstructive pulmonary disease (COPD), and pulmonary tuberculosis (TB) are common lung diseases associated with lung cancer mortality. This study evaluated sex disparities in pre-existing pulmonary diseases and stage-dependent lung adenocarcinoma survival.Patients newly diagnosed with lung adenocarcinoma between 2003 and 2008 were identified using the National Health Insurance Research Database and Cancer Registry. Cases with lung adenocarcinoma were followed until the end of 2010. Survival curves were estimated by the Kaplan-Meier method. Cox proportional-hazard regression was used to calculate the hazard ratio (HR) of pre-existing asthma, COPD, and/or TB, and to estimate all-cause mortality risk in patients with different stages of lung adenocarcinoma.A total of 14,518 cases were identified with lung adenocarcinoma. Specifically, among men, the HRs for TB were 1.69 (95% confidence interval [CI], 1.10-2.58), 1.48 (95% CI, 1.14-1.93), and 1.27 (95% CI, 1.08-1.49) for individuals with stage I + II, III, and IV diseases, respectively. The HRs for asthma were 1.41 (95% CI, 1.00-1.99) in women with stage I + II and 1.14 (95% CI, 1.04-1.26) in men with stage IV disease. For pulmonary disease combinations in men, the HRs were 1.45 (95% CI, 1.12-1.89) for asthma + COPD + TB, 1.35 (95% CI, 1.12-1.63) for COPD + TB, 1.28 (95% CI, 1.01-1.63) for TB, and 1.15 (95%CI, 1.04-1.27) for asthma + COPD, respectively. For women with stage I + II disease, the HR was 6.94 (95% CI, 2.72-17.71) for asthma + COPD + TB.Coexistence of pre-existing pulmonary diseases increased mortality risk in men with adenocarcinoma. TB is at elevated risk of mortality among men with different stages of adenocarcinoma. Asthmatic women with early-stage adenocarcinoma had increased risk of mortality.

The Impact of Coexisting Asthma, Chronic Obstructive Pulmonary Disease and Tuberculosis on Survival in Patients with Lung Squamous Cell Carcinoma

BACKGROUND

Pulmonary diseases [asthma, chronic obstructive pulmonary disease (COPD), and tuberculosis (TB)] are associated with lung cancer mortality. However, the relationship between coexisting pulmonary diseases and survival in patients with lung squamous cell carcinoma (SqCC) has not been well defined.

METHODS

Patients newly diagnosed with SqCC between 2003 and 2008 were identified by linking the National Health Insurance Research Database and Taiwan Cancer Registry Database. Cases with SqCC were followed up until death, loss to follow-up, or study end in 2010. Information on health status, date of death and the main causes of death was ascertained from the National Death Registry Database. Cox proportional hazard regression was used to calculate the hazard ratio (HR) of coexisting asthma, COPD and/or TB.

RESULTS

During the study period, a total of 5406 cases with SqCC were enrolled. For all cause-mortality, HRs were 1.08 [95% confidence interval (CI), 0.99-1.18], 1.04 (95% CI, 0.97-1.12), and 1.14 (95% CI, 1.00-1.31) for individuals with asthma, COPD, and TB, respectively. Specifically, among men with coexisting pulmonary diseases, the HRs were 1.56 (95% CI, 1.23-1.97) and 1.11 (95% CI, 1.00-1.24) for individuals with asthma+COPD+TB and asthma+COPD, respectively. Among male patients with stage III SqCC, HRs were 3.41 (95%CI, 1.27-9.17) and 1.65 (95%CI, 1.10-2.47) for individuals with asthma+TB and asthma+COPD+TB, respectively. Among male patients with stage IV SqCC, HRs were 1.40 (95%CI, 1.00-1.97) and 1.25 (95%CI, 1.03-1.52) for individuals with asthma+ COPD+TB and asthma. Among female patients with stage I and II, HR was 0.19 (95%CI, 005-0.77) for individuals with asthma.

CONCLUSIONS

Coexisting pulmonary diseases increased the risk of mortality from SqCC in male patients. For female patients with early stage SqCC, pre-existing asthma decreased mortality. These patients deserve greater attention while undergoing cancer treatment.

Impact of coexisting pulmonary diseases on survival of patients with lung adenocarcinoma: a STROBE-compliant article

Asthma, chronic obstructive pulmonary disease (COPD), and pulmonary tuberculosis (TB) are common pulmonary diseases associated with lung cancer. Besides, smoking is more prevalent in Taiwanese men. This study evaluated gender disparities in coexisting pulmonary diseases on survival of patients with lung adenocarcinoma. Patients newly diagnosed with lung cancer between 2003 and 2008 were identified from Taiwan National Health Insurance Research Database. Cases with lung adenocarcinoma were further confirmed using the Cancer Registry Database and followed up until the end of 2010. Cox proportional hazard regression was used to calculate the hazard ratio (HR) of coexisting asthma, COPD, and/or TB to estimate all-cause mortality risk. During the study period, 13,399 cases of lung adenocarcinoma were identified. The HRs of adenocarcinoma in men and women were 1.20 (95% confidence interval [CI], 1.10-1.30) and 1.05 (95% CI, 0.95-1.16), respectively, for individuals with asthma, 1.32 (95% CI, 1.16-1.51) and 0.97 (95% CI, 0.89-1.05), respectively, for COPD, and 0.99 (95% CI, 0.93-1.06) and 1.06 (95% CI, 0.86-1.32), respectively, for individuals with TB. Specifically, among men with coexisting pulmonary diseases, the HRs were 1.63 (95% CI, 1.25-2.13), 1.31 (95% CI, 1.08-1.59), and 1.23 (95% CI, 1.11-1.36) for individuals with asthma + COPD + TB, asthma + COPD, and COPD + TB, respectively. However, there was no increase risk of mortality among women with coexisting pulmonary diseases. Coexisting pulmonary diseases are at an elevated risk of mortality among male patients with lung adenocarcinoma. Such patients deserve greater attention while undergoing cancer treatment.

The coexistence of common pulmonary diseases on the histologic type of lung cancer in both genders in Taiwan: a STROBE-compliant article

Effects of pulmonary diseases [asthma, chronic obstructive pulmonary disease (COPD), and lung tuberculosis (TB)] on subsequent lung cancer development have been reported. However, whether patients with coexisting pulmonary diseases are at greater risk of developing various histologic types of lung cancer remains elusive. Patients newly diagnosed with lung cancer between 2004 and 2008 were identified from National Health Insurance Research Database (Taiwan). The histologic types of lung cancer were further confirmed using Taiwan Cancer Registry Database. Cox proportional hazard regression was used to calculate the hazard ratio (HR) of coexisting asthma, COPD and/or TB to estimate lung cancer risk by histologic type. During the study period, 32,759 cases of lung cancer were identified from 15,219,024 residents age 20 years and older, who were free from the disease before 2003. Coexisting pulmonary diseases showed stronger association with lung cancer than specific lung disorders. Specifically, among men, the HRs for squamous cell carcinoma (SqCC) were 3.98 (95% CI, 3.22-4.93), 2.68 (95% CI, 2.45-2.93), and 2.57 (95% CI, 2.10-3.13) for individuals with asthma+COPD+TB, asthma+COPD, and COPD+TB, respectively. Among women, the HRs for SqCC were 3.64 (95% CI, 1.88-7.05), 3.35 (95% CI, 1.59-7.07), and 2.21 (95% CI, 1.66-2.94) for individuals with TB, COPD+TB, and asthma+COPD, respectively. Adenocarcinoma HRs for men and women were 2.00 (95% CI, 1.54-2.60) and 2.82 (95% CI, 1.97-4.04) for individuals with asthma+COPD+TB, 2.28 (95% CI, 1.91-2.73) and 2.16 (95% CI, 1.57-2.95) for COPD+TB, and 1.76 (95% CI, 1.04-2.97) and 2.04 (95% CI, 1.02-4.09) for individuals with asthma+TB. Specifically, small cell carcinoma (SmCC) HRs among men were 3.65 (95% CI, 1.97-6.80), 2.20 (95% CI, 1.45-3.36), and 2.14 (95% CI, 1.86-2.47) for those with asthma+TB, asthma+COPD+TB, and asthma+ COPD, respectively. Among women, the HRs of SmCC were 8.97 (95% CI, 3.31-24.28), 3.94 (95% CI, 1.25-12.35) and 3.33 (95% CI, 2.23-4.97) for those with asthma+COPD+TB, COPD+TB, and asthma+COPD, respectively. Patients with coexistence of pulmonary diseases were more susceptible to lung cancer. Affected persons deserve greater attention while undergoing cancer screening.

[Asthma in the elderly]

Asthma is a common condition in the elderly although often confounded with chronic obstructive pulmonary disease (COPD) in this population. Asthma in the elderly seems to represent a specific phenotype characterized by more severe, but often less perceived, airway obstruction, a neutrophilic or mixed-type of airway inflammation and frequent comorbidities. Patients aged 65 years and over have an increased asthma-related morbidity and mortality compared to younger patients, probably due to difficulties in regard to diagnosis, assessment of the disease severity and treatment. Research is urgently needed to determine the optimal treatment of the aged patient. In this document we will review the state of knowledge on this topic and discuss the challenges of multidisciplinary asthma management in the elderly.

Chronic disease burden among cancer survivors in the California Behavioral Risk Factor Surveillance System, 2009-2010

PURPOSE

The California Behavioral Risk Factor Surveillance System estimates that 56.6 % of cancer survivors report ever being diagnosed with a chronic disease. Few studies have assessed potential variability in comorbidity by cancer type.

METHODS

We used data collected from a representative sample of adult participants in the 2009 and 2010 California Behavioral Risk Factor Surveillance System (n = 18,807). Chronic diseases were examined with cancer survivorship in case/non-case and case/case analyses. Prevalence ratios (PR) and corresponding 95 % confidence intervals (95 % CI) were estimated using Cox proportional hazards models, with adjustment on race, sex, age, education, smoking, and drinking.

RESULTS

Obesity was associated with gynecological cancers (PR 1.74; 95 % CI 1.26-2.41), and being overweight was associated with gynecological (PR 1.40; 95 % CI 1.05-1.86) and urinary (PR 2.19; 95 % CI 1.21-3.95) cancers. Arthritis was associated with infection-related (PR 1.78; 95 % CI 1.12-2.83) and hormone-related (PR 1.20; 95 % CI 1.01-1.42) cancers. Asthma was associated with infection- (PR 2.26; 95 % CI 1.49-3.43), hormone- (PR 1.46; 95 % CI 1.21-1.77), and tobacco- (PR 1.86; 95 % CI 1.25-2.77) related cancers. Chronic obstructive pulmonary disease (COPD) was associated with infection- (PR 2.16; 95 % CI 1.22-3.83) and tobacco-related (PR 2.24; 95 % CI 1.37-3.66) cancers and with gynecological cancers (PR 1.60; 95 % 1.00-2.56).

CONCLUSIONS

This is the first study to examine chronic disease burden among cancer survivors in California. Our findings suggest that the chronic disease burden varies by cancer etiology.

IMPLICATIONS FOR CANCER SURVIVORS

A clear need has emerged for future biological and epidemiological studies of the interaction between chronic disease and cancer etiology in survivors.

Epidemiology of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Ever since a lung cancer epidemic emerged in the mid-1900 s, the epidemiology of lung cancer has been intensively investigated to characterize its causes and patterns of occurrence. This report summarizes the key findings of this research.

METHODS

A detailed literature search provided the basis for a narrative review, identifying and summarizing key reports on population patterns and factors that affect lung cancer risk.

RESULTS

Established environmental risk factors for lung cancer include smoking cigarettes and other tobacco products and exposure to secondhand tobacco smoke, occupational lung carcinogens, radiation, and indoor and outdoor air pollution. Cigarette smoking is the predominant cause of lung cancer and the leading worldwide cause of cancer death. Smoking prevalence in developing nations has increased, starting new lung cancer epidemics in these nations. A positive family history and acquired lung disease are examples of host factors that are clinically useful risk indicators. Risk prediction models based on lung cancer risk factors have been developed, but further refinement is needed to provide clinically useful risk stratification. Promising biomarkers of lung cancer risk and early detection have been identified, but none are ready for broad clinical application.

CONCLUSIONS

Almost all lung cancer deaths are caused by cigarette smoking, underscoring the need for ongoing efforts at tobacco control throughout the world. Further research is needed into the reasons underlying lung cancer disparities, the causes of lung cancer in never smokers, the potential role of HIV in lung carcinogenesis, and the development of biomarkers.

Asthma and lung cancer risk: a systematic investigation by the International Lung Cancer Consortium

Asthma has been hypothesized to be associated with lung cancer (LC) risk. We conducted a pooled analysis of 16 studies in the International Lung Cancer Consortium (ILCCO) to quantitatively assess this association and compared the results with 36 previously published studies. In total, information from 585 444 individuals was used. Study-specific measures were combined using random effects models. A meta-regression and subgroup meta-analyses were performed to identify sources of heterogeneity. The overall LC relative risk (RR) associated with asthma was 1.28 [95% confidence intervals (CIs) = 1.16-1.41] but with large heterogeneity (I(2) = 73%, P < 0.001) between studies. Among ILCCO studies, an increased risk was found for squamous cell (RR = 1.69, 95%, CI = 1.26-2.26) and for small-cell carcinoma (RR = 1.71, 95% CI = 0.99-2.95) but was weaker for adenocarcinoma (RR = 1.09, 95% CI = 0.88-1.36). The increased LC risk was strongest in the 2 years after asthma diagnosis (RR = 2.13, 95% CI = 1.09-4.17) but subjects diagnosed with asthma over 10 years prior had no or little increased LC risk (RR = 1.10, 95% CI = 0.94-1.30). Because the increased incidence of LC was chiefly observed in small cell and squamous cell lung carcinomas, primarily within 2 years of asthma diagnosis and because the association was weak among never smokers, we conclude that the association may not reflect a causal effect of asthma on the risk of LC.

Reproductive and hormonal factors and lung cancer risk in the NIH-AARP Diet and Health Study cohort

BACKGROUND

Lung cancer exhibits unique patterns among women including high adenocarcinoma rates among nonsmokers. Inconsistent findings about hormonal factors on risk may reflect incomplete control for confounding, misclassification of exposures, or insufficient attention to variation by histology.

METHODS

Among 185,017 women, ages 50 to 71 years, recruited during 1995 and 1996 for the NIH-AARP (American Association of Retired Persons) Diet and Health Study, we identified 3,512 incident lung cancers (including 276 in never smokers) in follow-up through December 2006. Multivariable Cox proportional hazards models estimated relative risks (RR) and 95% CIs for self-reported hormonally related risk factors.

RESULTS

After adjustment for smoking and other confounders, subjects with late menarche were at reduced risk, with the association specific for adenocarcinomas (RR = 0.72 for menarche 15+ vs. <11, P(trend) < 0.01). Subjects with early ages at ovarian cessation (either from natural menopause or bilateral oophorectomy) were at an increased risk for adenocarcinomas and squamous cell tumors, but the associations were strongest for smokers, suggesting either residual confounding or an enhanced effect of menopausally related factors among subjects with decreased endogenous estrogens. In contrast, we saw no relationships of risk with either parity, age at first birth, or exogenous hormone use.

CONCLUSIONS

Elevated levels of hormones may adversely affect lung function early in life while assisting with cellular and immunologic responses later in life. Additional attention toward the role of hormonal factors may further our understanding of lung carcinogenesis.

IMPACT

Our findings provide some support for a role of hormonal factors in the etiology of lung cancer, although the mechanisms appear complicated.

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

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

Polymorphisms in inflammatory pathway genes, host factors and lung cancer risk in Chinese female never-smokers

Inflammation appears to be important in lung carcinogenesis among smokers, but its role among never-smokers is not well established. We hypothesized that inflammatory medical conditions and gene polymorphisms interact to increase lung cancer risk in never-smokers. We interviewed 433 Singaporean female never-smoker lung cancer patients and 1375 hospital controls, and evaluated six polymorphisms in the interleukin 1-β, interleukin 6 (IL6), cyclooxygenase-2, peroxisome proliferator-activated receptor-γ and interleukin 1-β receptor antagonist (IL1RN) genes. Tuberculosis was associated with a non-significant elevated risk of lung cancer [odds ratio (OR) 1.58, 95% confidence interval (CI) 0.95-2.62]. There was no effect of asthma, atopy or chronic productive cough individually. However, the presence of one or more of these conditions (asthma, cough or atopy) increased risk (OR 2.24, 95%CI 1.15-4.38) in individuals possessing the T/T genotype at interleukin 1-β -31T/C, but not in those possessing the C/T (OR 0.87, 95%CI 0.51-1.57) or C/C genotypes (OR 0.58, 95%CI 0.27-1.27), and in individuals having the *2 variable number of tandem repeat allele of IL1RN [OR 5.09 (1.39-18.67)], but not in those without (OR 0.93, 95%CI 0.63-1.35). The IL6-634 G allele increased the risk of lung cancer (OR 1.44, 95%CI 1.07-1.94). Lung cancer risk also increased with the number of polymorphism sites where at least 1 'risk' allele was present [interleukin 1-β -31T/C (T allele), IL1RN (*2 allele) and IL6-634C/G (G allele)] among those with asthma, cough or atopy (Ptrend 0.001) but not in those without (Ptrend 0.47). Our results suggest that the effect of inflammatory medical conditions on lung cancer in never-smokers is modulated by host genetic susceptibility and will need to be confirmed in other studies conducted in similar populations.

Allergic inflammation does not impact chemical-induced carcinogenesis in the lungs of mice

BACKGROUND

Although the relationship between allergic inflammation and lung carcinogenesis is not clearly defined, several reports suggest an increased incidence of lung cancer in patients with asthma. We aimed at determining the functional impact of allergic inflammation on chemical carcinogenesis in the lungs of mice.

METHODS

Balb/c mice received single-dose urethane (1 g/kg at day 0) and two-stage ovalbumin during tumor initiation (sensitization: days -14 and 0; challenge: daily at days 6-12), tumor progression (sensitization: days 70 and 84; challenge: daily at days 90-96), or chronically (sensitization: days -14 and 0; challenge: daily at days 6-12 and thrice weekly thereafter). In addition, interleukin (IL)-5 deficient and wild-type C57BL/6 mice received ten weekly urethane injections. All mice were sacrificed after four months. Primary end-points were number, size, and histology of lung tumors. Secondary end-points were inflammatory cells and mediators in the airspace compartment.

RESULTS

Ovalbumin provoked acute allergic inflammation and chronic remodeling of murine airways, evident by airspace eosinophilia, IL-5 up-regulation, and airspace enlargement. Urethane resulted in formation of atypical alveolar hyperplasias, adenomas, and adenocarcinomas in mouse lungs. Ovalbumin-induced allergic inflammation during tumor initiation, progression, or continuously did not impact the number, size, or histologic distribution of urethane-induced pulmonary neoplastic lesions. In addition, genetic deficiency in IL-5 had no effect on urethane-induced lung tumorigenesis.

CONCLUSIONS

Allergic inflammation does not impact chemical-induced carcinogenesis of the airways. These findings suggest that not all types of airway inflammation influence lung carcinogenesis and cast doubt on the idea of a mechanistic link between asthma and lung cancer.

Occupation, gender, race, and lung cancer

OBJECTIVE

To examine associations between occupation and lung cancer by gender and race.

METHODS

We used data from the Maryland Lung Cancer Study of nonsmall cell lung carcinoma (NSCLC), a multicenter case control study, to estimate odds ratios (ORs) of NSCLC in different occupations.

RESULTS

After adjusting for smoking, environmental tobacco smoke, and other covariates, NSCLC ORs among women but not men were elevated in clerical-sales, service, and transportation-material handling occupations; ORs were significantly increased in all three categories (OR [95% confidence interval]: 4.07 [1.44 to 11.48]; 5.15 [1.62 to 16.34]; 7.82 [1.08 to 56.25], respectively), among black women, but only in transportation-material handling occupations (OR [95% confidence interval[: 3.43 [1.02 to 11.50]) among white women.

CONCLUSIONS

Women, especially black women, in certain occupations had increased NSCLC ORs.

Allergies: their role in cancer prevention

The nature of the biological relationships between cancers and allergies has intrigued researchers and health care providers for five decades. Three hypotheses have been proposed: antigenic stimulation predicts positive associations between cancers and allergies (i.e., allergy sufferers are more likely to get cancer), whereas immunosurveillance and prophylaxis predict inverse associations (i.e., allergy sufferers are less likely to get cancer). Immunosurveillance predicts inverse associations for cancers of all tissues and organ systems, and prophylaxis predicts inverse associations specifically for cancers of tissues and organ systems that interface with the external environment. To comparatively evaluate these hypotheses, we comprehensively reviewed the literature on cancer and allergies. We located 148 papers published from 1955 through 2006 that reported results of 463 studies of relationships between patients' histories of 11 specific allergies and cancers of 19 tissues and organ systems, and 183 studies of patients' histories of multiple allergies in relation to various types/sites of cancers. Analyses of these studies revealed that (1) frequencies of positive, inverse, and null allergy-cancer associations differed considerably among cancers of different tissues and organ systems; (2) more than twice as many studies reported inverse allergy-cancer associations as reported positive associations; (3) inverse associations were particularly common for cancers of the mouth and throat, brain glia, colon and rectum, pancreas, skin, and cervix but (4) particularly rare for cancers of the breast, prostate, and brain meninges, and for myeloma, non-Hodgkin's lymphoma, and myelocytic leukemia; (5) lung cancer was positively associated with asthma but inversely associated with other allergies; (6) inverse associations with allergies were more than twice as common for cancers of nine tissues and organ systems that interface with the external environment compared to cancers of nine tissues and organ systems that do not interface with the external environment; and (7) eczema, hives, and allergies to animal dander and food were most frequently inversely associated with cancers of tissues that interface with the external environment. Taken together, these results are more consistent with the prophylaxis hypothesis than the two alternatives. IgE is a widespread and ancient immunoglobulin isotype in mammals, occurring among all known marsupials, monotremes, and eutherians. The IgE system and its associated allergy symptoms may serve a common protective function: the rapid expulsion of pathogens, dangerous natural toxins, and other carcinogenic antigens before they can trigger malignant neoplasia in exposed tissues.

Previous pulmonary disease and family cancer history increase the risk of lung cancer among Hong Kong women

Chinese women in Hong Kong have among the highest incidence and mortality of lung cancer in the world, in spite of a low prevalence of smoking. We carried out this population-based case-control study to evaluate the associations of previous lung disease and family cancer history with the occurrence of lung cancer among them. We selected 212 cases that were newly diagnosed with primary lung cancer, and randomly sampled 292 controls from the community, frequency matched by age group. All the cases and controls were lifetime nonsmokers. We estimated the main effects of preexisting asthma, pulmonary tuberculosis, pneumonia, chronic bronchitis, and family lung/all cancer history, using unconditional logistic regression, accounting for various potential risk factors and confounders. All of the previous lung diseases, except chronic bronchitis, were related to an elevated risk for lung cancer, and the association with asthma was significant. Those who had more than one previous lung disease tended to be at higher risk than those with only one of them. Positive family history of any cancer was associated with over 2-fold risk than negative family history. The joint effect of positive history of previous pulmonary diseases and positive family cancer history appeared to be additive, indicating the two factors acted independently. The results support an etiological link of preexisting lung disease and family cancer history to the risk of lung cancer.

Dietary magnesium and DNA repair capacity as risk factors for lung cancer

Magnesium (Mg) is required for maintenance of genomic stability; however, data on the relationship between dietary Mg intake and lung cancer are lacking. In an ongoing lung cancer case-control study, we identified 1139 cases and 1210 matched healthy controls with data on both diet and DNA repair capacity (DRC). Dietary intake was assessed using a modified Block-NCI food frequency questionnaire and DRC was measured using the host-cell reactivation assay to assess repair in lymphocyte cultures. After adjustment for potential confounding factors including DRC, the odds ratios (ORs) and 95% confidence intervals (CIs) for lung cancer with increasing quartiles of dietary Mg intake were 1.0, 0.83 (0.66-1.05), 0.64 (0.50-0.83) and 0.47 (0.36-0.61), respectively, for all subjects (P-trend < 0.0001). Similar results were observed by histology and clinical stage of lung cancer. Low dietary Mg intake was associated with poorer DRC and increased risk of lung cancer. In joint effects analyses, compared with those with high dietary Mg intake and proficient DRC, the OR (95% CI) for lung cancer in the presence of both low dietary Mg and suboptimal DRC was 2.36 (1.83-3.04). Similar results were observed for men and women. The effects were more pronounced among older subjects (>60 years), current or heavier smokers, drinkers, those with a family history of cancer in first-degree relatives, small cell lung cancer and late-stage disease. These intriguing results need to be confirmed in prospective studies.

Oxidant stress and B vitamins status in patients with non-small cell lung cancer

In this study, we examined oxidative stress and B vitamins status in non-small cell lung cancer (NSCLC) patients at different stages. NSCLC patients were divided into 2 groups, stage III (IIIA + IIIB, n = 27) and stage IV (n = 23). A total of 16 healthy control subjects were included for comparison. Plasma levels of alpha-tocopherol, beta-carotene, vitamin C, Se, Cu, Zn, reduced glutathione (GSH), oxidized glutathione (GSSG), lipid oxidation and the activities of glutathione peroxidase (GPX), superoxide dismutase (SOD), catalase, and xanthine oxidase (XO) were determined for evaluating oxidative status in these subjects. B vitamins (B(1), B(2), B(6), B(12), folate) in blood and plasma ghrelin level in these subjects were analyzed. Results showed that plasma level of ghrelin and lipid oxidation in NSCLC patients were significantly greater than control groups (P < 0.05). The activity of GPX, SOD, or catalase was significantly reduced, but XO activity was significantly elevated in NSCLC patients (P < 0.05). Plasma level of GSH was significantly lower, but GSSG level was significantly increased in NSCLC patients (P < 0.05). Vitamins B(2) and B(6) levels in red blood cells (RBC) from NSCLC patients were significantly lower (P < 0.05), and both were negatively correlated with plasma ghrelin. The correlation coefficients were -0.788 and -0.752, respectively. These data suggest that plasma GSH level may be a proper biomarker for evaluating oxidation status for NSCLC patients. RBC levels of vitamins B2 and B6 were reduced in NSCLC patients; thus, the importance of vitamins B(2) and B(6) for NSCLC patients could not be ignored.

Diesel particulate matter, lung cancer, and asthma incidences along major traffic corridors in MA, USA: A GIS analysis

By examining the census tracts and towns that are intersected by Massachusetts' major highway corridors, Diesel and Health along Massachusetts' Highway Corridors ascertains whether these areas contain significantly higher rates of diesel particulate matter (DPM), lung cancer, and asthma. DPM was significantly higher for corridor towns than non-corridor towns. Hot spot analysis revealed statistically significant clustering of elevated DPM concentrations and asthma incidence in certain towns. The location of these towns was compared to the location of environmental justice neighborhoods. The authors recommend a series of steps that can be taken by policy makers and planners to curb DPM emissions.

Epidemiology of lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition)

BACKGROUND

The objective of this study was to summarize the published literature concerning the epidemiology of lung cancer.

METHODS

A narrative review of published evidence was conducted, identifying and summarizing key reports that describe the occurrence of lung cancer in populations and factors that affect lung cancer risk.

RESULTS

In the United States, lung cancer remains the leading cause of cancer death in both men and women, even though an extensive list of modifiable risk factors has long been identified. The predominant cause of lung cancer is exposure to tobacco smoke, with active smoking causing most cases but passive smoking also contributing to the lung cancer burden.

CONCLUSIONS

The reductions in smoking prevalence in men that occurred in the late 1960s through the 1980s will continue to drive lung cancer mortality rates downward in men during the first portion of this century, but rates in women have not yet begun to decrease. Fortunately, exposures to major occupational respiratory carcinogens have largely been controlled, but the population is still exposed to environmental causes of lung cancer, including radon, the second leading cause of lung cancer death.

Inhaled corticosteroids and risk of lung cancer among patients with chronic obstructive pulmonary disease

RATIONALE AND OBJECTIVES

Lung cancer is a frequent cause of death among patients with chronic obstructive pulmonary disease (COPD). We examined whether the use of inhaled corticosteroids among patients with COPD was associated with a decreased risk of lung cancer.

METHODS

We performed a cohort study of United States veterans enrolled in primary care clinics between December 1996 and May 2001. Participants had received treatment for, had an International Classification of Disease, 9th edition, diagnosis of, or a self-reported diagnosis of COPD. Patients with a history of lung cancer were excluded. To be exposed, patients must have been at least 80% adherent to inhaled corticosteroids. We used Cox regression models to estimate the risk of cancer and adjust for potential confounding factors.

FINDINGS

We identified 10,474 patients with a median follow-up of 3.8 years. In comparison to nonusers of inhaled corticosteroids, adjusting for age, smoking status, smoking intensity, previous history of non-lung cancer malignancy, coexisting illnesses, and bronchodilator use, there was a dose-dependent decreased risk of lung cancer associated with inhaled corticosteroids (ICS dose < 1,200 mug/d: adjusted HR, 1.3; 95% confidence interval, 0.67-1.90; ICS dose >or= 1,200 microg/d: adjusted HR, 0.39; 95% confidence interval, 0.16-0.96). Changes in cohort definitions had minimal effects on the estimated risk. Analyses examining confounding by indication suggest biases in the opposite direction of the described effects.

INTERPRETATION

Results suggest that inhaled corticosteroids may have a potential role in lung cancer prevention among patients with COPD. These initial findings require confirmation in separate and larger cohorts.

Bronchial epilepsy or broncho-pulmonary hyper-excitability as a model of asthma pathogenesis

Over the last 20 years, the prevalence of asthma has nearly doubled in industrialized countries. A similar increase has been predicted for the next two decades. Asthma is major illness in terms of morbidity and suffering, asthma is the leading cause of hospitalizations in children under 15 years of age. According to many top experts, asthma is correctly characterized as a syndrome rather than disease. This lack of definition for asthma makes the search for a cause, prevention and potential cure elusive. Episodic airway obstruction and reversible bronchial hyperresponsiveness to non-specific irritants are the major symptoms of asthma. Airway inflammation is now widely accepted as the key factor underlying the pathogenesis of asthma. However, many patients show no signs of inflammation, yet they still have severe airflow limitation and asthma symptoms. The primary clinical symptoms of asthma are attacks of shortness of breath, wheezing, and coughing resulting from excessive and inappropriate constriction of the airway smooth muscle. Our research suggests a possible epileptic or hyper-excitatory condition of bronchial system in asthma pathogenesis. The paroxysmal, spasmodic character of asthma attacks may be similar to seizures. We propose a unified pathogenetic mechanism of asthma as a syndrome of inducible or genetically predisposed membrane hyper-excitability (bronchial epilepsy).