Relation of forced expiratory volume in one second (FEV1) to lung cancer mortality in the Multiple Risk Factor Intervention Trial (MRFIT)

Unraveling the link between cardiorespiratory fitness and cancer: a state-of-the-art review

Cardiorespiratory fitness (CRF) not only reflects an individual's capacity to perform physical activities but also encapsulates broader effects on the basic biology of aging. This review aims to summarize the evidence on the influence of CRF on overall and site-specific cancer risks. It delves into the biological mechanisms through which CRF may exert its effects, explores the clinical implications of these findings, identifies gaps in the current evidence base, and suggests directions for future research. The synthesis of findings reveals that higher CRF levels (general threshold of > 7 METs) are consistently associated with a reduced risk of a range of cancers, including head and neck, lung, breast, gastrointestinal, particularly pancreatic and colorectal, bladder, overall cancer incidence and mortality, and potentially stomach and liver, bile duct, and gall bladder cancers. These inverse associations between CRF and cancer risk do not generally differ across age groups, sex, race, or adiposity, suggesting a universal protective effect of CRF. Nonetheless, evidence linking CRF with skin, mouth and pharynx, kidney, and endometrial cancers is limited and inconclusive. Conversely, higher CRF levels may be potentially linked to an increased risk of prostate cancer and hematological malignancies, such as leukemia and myeloma, although the evidence is still not conclusive. CRF appears to play a significant role in reducing the risk of several cancers through various biological mechanisms, including inflammation reduction, immune system enhancement, hormonal regulation, and metabolic improvements. Overall, enhancing CRF through regular physical activity offers a vital, accessible strategy for reducing cancer risk and extending the health span. Future research should aim to fill the existing evidence gaps regarding specific cancers and elucidate the detailed dose-response relationships between CRF levels and cancer risk. Studies are also needed to elucidate the causal relationships and mechanistic pathways linking CRF to cancer outcomes.

Prognostic value of the serum creatinine/cystatin C ratio in patients with chronic obstructive pulmonary disease

BACKGROUND

Sarcopenia, characterized by skeletal muscle atrophy and physical inactivity, is a manifestation of chronic obstructive pulmonary disease (COPD) and is associated with a poor prognosis. The serum creatinine (Cr)/cystatin C (CysC) ratio has been proposed as a marker of sarcopenia, given its correlation with total skeletal muscle mass, and as a prognostic indicator in COPD. This study aimed to evaluate the usefulness of the serum Cr/CysC ratio as a prognostic determinant in these patients.

METHODS

A total of 124 outpatients with COPD were enrolled in this study. Their serum Cr and CysC levels were measured. Survival time analyses were conducted to compare mortality rates between the low and high serum Cr/CysC ratio groups. Multivariate analysis was performed to investigate the association between various factors.

RESULTS

Using a serum Cr/CysC cut-off value of 0.885, the mortality rate (per 1000 person-years) for overall mortality was significantly higher in the low serum Cr/CysC ratio group (69.2 versus 28.6; hazard ratio, 2.47; 95% confidence interval, 1.06-5.79; p < 0.05). Similarly, the mortality rate due to respiratory disease was also higher (37.8 versus 8.2; hazard ratio, 4.68; 95% confidence interval, 1.05-20.9; p < 0.05). Multivariate Cox proportional hazards analysis revealed that serum Cr/CysC was an independent risk factor for respiratory disease mortality, regardless of age and airflow limitations.

CONCLUSIONS

The serum Cr/CysC ratio could be a valuable clinical parameter for identifying sarcopenia and severe airflow obstruction. The study findings highlight the utility of this ratio as a prognostic predictor in patients with COPD.

View Score: An early warning score to detect possible complications among COVID-19 patients

Introduction

Understanding pulmonary function at various phases after coronavirus disease 2019 (COVID-19) infection is critical for determining the exact pathophysiological mechanism of COVID-19.

Research Question

What is the correlation between spirometry indices and clinical indicators in COVID-19 patients over a 6-week follow-up?

Objectives

1) To assess deterioration or improvement in spirometry parameters including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and ratio FEV1/FVC in COVID-19 patients. 2) To study the correlation between FVC, FEV1, and FEV1/FVC with oxygen saturation and clinical findings.

Materials and Methods

A prospective observational study was conducted for a 6-week period among 25, COVID-19 patients who were either asymptomatic or mildly symptomatic. Each patient received a home-use-connected spirometer-SpiroPRO®, a pulse oximeter, and a thermometer from Briota Technologies Pvt Ltd. (BRIOTA). Patients and healthcare professionals were given training for performing spirometry twice a day as well as access to mobile apps was provided. Spirometry indices, patient symptoms, and vital statistics were used to calculate the VIEW™ score using machine learning algorithms.

Result

The Bland-Altman plots showed that FEV1 reduced slightly up to 21-28 days and comes back to normal around 42 days. VIEW™ score increased up to day 21 and then decreased toward day 42. An increase in VIEW™ score increases the risk of COVID-19 complications. VIEW™ score and FEV1 showed a significant correlation.

Conclusion

Home-based spirometry acts as an effective tool for COVID-19 patients to predict lung complications and also promote self-monitoring thereby reducing the burden on the health system.

Risk Factors for Cancer Mortality in Spain: Population-Based Cohort Study

BACKGROUND

Cancer is considered a major public health problem due to its increasing incidence and high mortality. This study aims to identify risk factors for cancer mortality in Spain.

METHODS

Retrospective population-based cohort study in 20,397 participants of the 2011/2012 National Health Survey in Spain. Risk factors associated with mortality due to neoplasm from 2011 to 2017 were analyzed, and hazard ratios were calculated with a multivariate Cox model with competing risks for mortality from other causes.

RESULTS

Myocardial infarction, chronic obstructive pulmonary disease, cirrhosis, and mental disorders were associated with an increased risk of mortality due to neoplasm. Male sex, age over 50 years, history or current smoking habit, negligible intake of legumes, and poorer self-perceived health were also associated with increased cancer mortality.

CONCLUSIONS

Comorbidities, tobacco use, poor diet, and worse self-perceived health were the main risk factors for cancer mortality in Spain.

Relationship between lung function and lung cancer risk: a pooled analysis of cohorts plus Mendelian randomization study

BACKGROUND

Since little consensus has been reached on whether milder reduction in forced expiratory volume in 1 s (FEV₁) increases lung cancer incidence, we conducted a meta-analysis and performed Mendelian randomization (MR) analysis to explore the association and causal relationship between FEV₁ and lung cancer incidence.

METHODS

We conducted a comprehensive search from PubMed, Medline, EMBASE, and Cochrane Library databases as of February 2020. MR analysis was performed using summary data obtained from two large consortia [International Lung Cancer Consortium (ILCCO) and Neale Lab] to assess the possible causality between FEV₁ and lung cancer risk.

RESULTS

Eight studies involving 88,743 cases were included. The incidence of lung cancer increased with decreasing FEV₁.The combined odds ratio (OR) of decreased FEV₁ for lung cancer incidence was 1.91 [95% confidence interval (CI) 1.67-2.19; P < 0.001]. Compared with the highest quintile of FEV₁ (quintile 5, > 100% of predicted), the OR was 3.06 (95% CI 2.20-4.24; P < 0.001) for quintile 1 (< 70% of predicted), 1.89 (95% CI 1.50-2.38; P < 0.001) for quintile 2 (70-80% of predicted), 1.53 (95% CI 1.31-1.79; P < 0.001) for quintile 3 (80-90% of predicted), and 1.64 (95% CI 1.18-2.28; P = 0.003) for quintile 4 (90-100% of predicted). In subgroup meta-analysis, the correlation between FEV₁ and lung cancer risk was different among men (OR = 1.74; 95% CI 1.49-2.03; P < 0.001) and women (OR = 2.80; 95% CI 1.87-4.19; P < 0.001). However, MR analysis showed no causality between the FEV₁ and lung cancer risk (OR = 1.199; 95% CI 0.958-1.500; P = 0.114).

CONCLUSION

FEV₁ is likely to be a predictor of lung cancer, especially for women. However, genetically decreased FEV₁ is not causally correlated with lung cancer incidence.

Conducting spirometry in occupational health at COVID-19 times: international standards

Spirometry is a commonly performed assessment of lung function for diagnostic purposes as well as for monitoring of chronic lung diseases. The last international standardization of this technique was published in 2005. After 14 years, a group of experts from two leading scientific societies, American Thoracic Society (ATS) and European Respiratory Society (ERS), published a joint position that updated the standardization of spirometry, with an extensive criteria re-organization, including key updates such as: relative contraindications, instrumentation requirement to meet the International Organization for Standardization (ISO) standards, quality assurance, operator training, pre-test requirements, acceptability and usability criteria. New standards underline three key elements to obtain high quality pulmonary function data: an accurate and precise instrumentation, a patient/subject capable of performing acceptable and repeatable measurements, and a motivated technologist to elicit maximum performance from the patient. Never- theless, although COVID-19 pandemic has enormously impacted and limited a widespread application of spirometry, it has prompted much attention on hygienic procedures and on further research on noncontact spirometers.

Epidemiology of lung cancer

Lung cancer is the leading cause of global cancer incidence and mortality, accounting for an estimated 2 million diagnoses and 1.8 million deaths. Neoplasms of the lungs are the second most common cancer diagnosis in men and women (after prostate and breast cancer, respectively). With increasing access to tobacco and industrialization in developing nations, lung cancer incidence is rising globally. The average age of diagnosis is 70 years old. Men are twice as likely to be diagnosed with lung cancer, which largely reflects differences in tobacco consumption, although women may be more susceptible due to higher proportions of epidermal growth factor receptor mutations and the effects of oestrogen. African American men in the US are at the highest risk of lung cancer. Family history increases risk by 1.7-fold, with a greater risk among first-degree relatives. Tobacco smoking is the greatest preventable cause of death worldwide, accounting for up to 90% of lung cancer cases, and continued consumption is projected to increase global cancer incidence, particularly in developing nations such as China, Russia, and India. Second-hand smoke among children and spouses has likewise been implicated. Radon from natural underground uranium decay is the second leading cause of lung cancer in the developed world. Occupational hazards such as asbestos and environmental exposures such as air pollution, arsenic, and HIV and Tb infection have all been implicated in lung carcinogenesis, while cannabis smoking, electronic cigarettes, heated tobacco products, and COVID-19 have been hypothesized to increase risk.

Statins dose-dependently exert a chemopreventive effect against lung cancer in COPD patients: a population-based cohort study

Purpose

Chronic obstructive pulmonary disease (COPD) is associated with increased lung cancer risk. We evaluated the association of statin use with lung cancer risk in COPD patients and identified which statins possess the highest chemopreventive potential.

Results

After adjustment for age, sex, CCI, diabetes, hypertension, dyslipidemia, urbanization level, and monthly income according to propensity scores, lung cancer risk in the statin users was lower than that in the statin nonusers (adjusted hazard ratio [aHR] = 0.37). Of the individual statins, lovastatin and fluvastatin did not reduce lung cancer risk significantly. By contrast, lung cancer risk in patients using rosuvastatin, simvastatin, atorvastatin, and pravastatin was significantly lower than that in statin nonusers (aHRs = 0.41, 0.44, 0.52, and 0.58, respectively). Statins dose-dependently reduced lung cancer risk in all subgroups and the main model with additional covariates (nonstatin drug use).

MATERIALS AND METHODS

The study cohort comprised all patients diagnosed with COPD at health care facilities in Taiwan (n = 116,017) between January 1, 2001 and December 31, 2012. Our final study cohort comprised 43,802 COPD patients: 10,086 used statins, whereas 33,716 did not. Patients were followed up to assess lung cancer risk or protective factors. In addition, we also considered demographic characteristics, namely age, sex, comorbidities (diabetes, hypertension, dyslipidemia, and Charlson comorbidity index [CCI]), urbanization level, monthly income, and nonstatin drug use. The index date of statin use was the COPD confirmation date. To examine the dose–response relationship, we categorized statin use into four groups in each cohort: < 28, 28–90, 91–365, and > 365 cumulative defined daily doses (cDDDs). Patients receiving < 28 cDDDs were defined as nonstatin users.

Conclusions

Statins dose-dependently exert a significant chemopreventive effect against lung cancer in COPD patients. Rosuvastatin, simvastatin, and atorvastatin exhibited the highest chemopreventive potential.

Chronic obstructive pulmonary disease and risk of lung cancer: a meta-analysis of prospective cohort studies

Background

Studies exploring the association between chronic obstructive pulmonary disease (COPD) and lung cancer have yielded mixed results. We conducted a meta-analysis of the published prospective cohort studies to have a clear understanding about this association.

Methods

We searched the MEDLINE and EMBASE databases from inception to December 31, 2016. Bibliographies were also reviewed for additional information. Random-effects model was used to calculate summary relative risk (SRR) and corresponding 95% confidence interval (CI).

Results

Eighteen prospective cohort studies were part of this meta-analysis, involving 12,442 lung cancer cases with a median duration of follow- up of 5 years (range: 1.5-20 years). A history of COPD, emphysema or chronic bronchitis conferred SRRs of 2.06 (95% CIs: 1.50-2.85; n=14 studies), 2.33 (95% CIs: 1.56-3.49; n=4 studies) and 1.17 (95%CIs: 0.79-1.73; n=3 studies), respectively. Stratification by COPD severity yielded SRR of 1.46 (95% CIs: 1.20-1.76) for mild, 2.05 (95% CIs: 1.67-2.52) for moderate and 2.44(95% CIs: 1.73-3.45) for severe COPD, respectively. There were similar risk estimations for never and ever smokers. The SRR was statistically higher for squamous cell cancer than that for adenocarcinoma and for small cell cancer of the lung (P<0.05).

Conclusion

This meta-analysis indicated a significantly increased risk of lung cancer for COPD, emphysema, but not for chronic bronchitis. For the prevention of lung cancer, it is of importance for early detection of COPD in lung cancer surveillance.

Spirometry: a predictor of lung cancer among asbestos workers

OBJECTIVE

The significance of lung function as an independent risk factor for lung cancer remains unclear. The objective of the study is to answer the question if spirometry can identify patients at risk for lung cancer among people occupationally exposed to asbestos dust in the past.

METHODS

In order to identify a group of individuals with the highest risk of lung cancer incidence based on lung function levels of FEV₁% predicted value, we examined 6882 subjects enrolled in the health surveillance program for asbestos related diseases over the years 2000-2014. We found a total of 110 cases confirmed as primary lung cancer.

RESULTS

Using Cox's proportional hazards model after adjustment for age, gender, number of cigarettes, duration of smoking and cumulative asbestos exposure, we estimated that compared with the subjects with FEV₁ ≥90% pred, the HR of lung cancer was 1.40 (95%CI: 0.94-2.08) for the subjects with FEV₁ less than 90% and 1.95 (HR = 1.86; 95%CI: 1.12-3.08) for those with FEV₁ less than 70%. In addition, probability of the occurrence of lung cancer for FEV₁ <90% of the predicted value was HR = 2.19 (95%CI: 1.04-4.61) in the subjects whose time since spirometry and cancer diagnosis was three years or less.

CONCLUSIONS

The results strongly support the hypothesis that spirometry can identify patients at a risk of lung cancer development. Regular spirometry should be offered to all patients with a history of asbestos exposure, at least once every three years.

Physical activity and sedentary behavior in relation to lung cancer incidence and mortality in older women: The Women's Health Initiative

Physical activity has been associated with lower lung cancer incidence and mortality in several populations. We investigated these relationships in the Women's Health Initiative Observational Study (WHI-OS) and Clinical Trial (WHI-CT) prospective cohort of postmenopausal women. The WHI study enrolled 161,808 women aged 50-79 years between 1993 and 1998 at 40 U.S. clinical centers; 129,401 were eligible for these analyses. Cox proportional hazards models were used to assess the association of baseline physical activity levels [metabolic equivalent (MET)-min/week: none <100 (reference), low 100 to <500, medium 500 to <1,200, high 1,200+] and sedentary behavior with total lung cancer incidence and mortality. Over 11.8 mean follow-up years, 2,148 incident lung cancer cases and 1,365 lung cancer deaths were identified. Compared with no activity, higher physical activity levels at study entry were associated with lower lung cancer incidence [p = 0.009; hazard ratios (95% confidence intervals) for each physical activity category: low, HR: 0.86 (0.76-0.96); medium, HR: 0.82 (0.73-0.93); and high, HR: 0.90 (0.79-1.03)], and mortality [p < 0.0001; low, HR: 0.80 (0.69-0.92); medium, HR: 0.68 (0.59-0.80); and high, HR: 0.78 (0.66-0.93)]. Body mass index (BMI) modified the association with lung cancer incidence (p = 0.01), with a stronger association in women with BMI < 30 kg/m(2) . Significant associations with sedentary behavior were not observed. In analyses by lung cancer subtype, higher total physical activity levels were associated with lower lung cancer mortality for both overall NSCLC and adenocarcinoma. In conclusion, physical activity may be protective for lung cancer incidence and mortality in postmenopausal women, particularly in non-obese women.

Statins Dose-Dependently Exert Significant Chemopreventive Effects Against Various Cancers in Chronic Obstructive Pulmonary Disease Patients: A Population-Based Cohort Study

PURPOSE: Chronic obstructive pulmonary disease (COPD) is associated with an increased cancer risk. We evaluated the chemopreventive effect of statins against all cancers in COPD patients and identified the statin with the strongest chemopreventive effect. PATIENTS AND METHODS: All patients diagnosed with COPD at health care facilities in Taiwan (n = 116,017) from January 1, 2001, to December 31, 2012, were recruited. Each patient was followed to assess the following protective and risk factors for all cancers: age; sex; comorbidities (diabetes, hypertension, dyslipidemia) and the Charlson comorbidity index [CCI]); urbanization level; monthly income; and nonstatin drug use. The index date of statins use was the date of COPD confirmation. Propensity scores (PSs) were derived using a logistic regression model to estimate the effect of statins by considering the covariates predicting intervention (statins) receipt. To examine the dose-response relationship, we categorized statin use into four groups in each cohort (<28 [statin nonusers], 28-90, 91-365, and >365 cumulative defined daily dose). RESULTS: After PS adjustment for age, sex, CCI, diabetes, hypertension, dyslipidemia, urbanization level, and monthly income, we analyzed the all-cancer risk. The adjusted hazard ratios (aHRs) for the all-cancer risk were lower among statin users than among statin nonusers (aHR = 0.46, 95% confidence interval: 0.43 to 0.50). The aHRs for the all-cancer risk were lower among patients using rosuvastatin, simvastatin, atorvastatin, pravastatin, and fluvastatin than among statin nonusers (aHRs = 0.42, 0.55, 0.59, 0.66, and 0.78, respectively). Sensitivity analysis indicated that statins dose-dependently reduced the all-cancer risk. CONCLUSION: Statins dose-dependently exert a significant chemopreventive effect against various cancers in COPD patients. In particular, rosuvastatin has the strongest chemopreventive effect.

The association of fitness with reduced cardiometabolic risk among smokers

INTRODUCTION

Despite the health benefits associated with smoking cessation, continued smoking and relapse following cessation are common. Physical activity is associated with reduced risk of cardiovascular disease in general, though less is known about how cardiorespiratory fitness may influence cardiometabolic risk among smokers. Strategies are needed to protect against the health consequences of smoking among those unwilling or unable to quit smoking. The purpose of this study is to determine whether greater cardiorespiratory fitness is associated with reduced metabolic risk among smokers.

METHODS

The prospective influence of estimated cardiorespiratory fitness (i.e., maximal METs) on the development of metabolic syndrome and its components were examined among adult smokers (N=1,249) who completed at least two preventive medical visits at the Cooper Clinic (Dallas TX) between 1979 and 2011. Statistical analyses were completed in 2013 and 2014.

RESULTS

The rate and risk for metabolic syndrome, as well as abnormal fasting glucose and high-density lipoprotein cholesterol levels declined linearly with increases in cardiorespiratory fitness (all p<0.05). Smokers in the moderate and high fitness categories had significantly reduced risk of developing metabolic syndrome and elevated fasting glucose relative to smokers in the lowest fitness category. In addition, smokers in the high fitness category were less likely to develop abnormal high-density lipoprotein cholesterol levels.

CONCLUSIONS

Moderate to high cardiorespiratory fitness among smokers is associated with a reduced likelihood of developing certain cardiovascular disease risk factors and metabolic syndrome.

Systematic review with meta-analysis of the epidemiological evidence relating FEV1 decline to lung cancer risk

Background

Reduced FEV₁ is known to predict increased lung cancer risk, but previous reviews are limited. To quantify this relationship more precisely, and study heterogeneity, we derived estimates of β for the relationship RR(diff) = exp(βdiff), where diff is the reduction in FEV₁ expressed as a percentage of predicted (FEV₁%P) and RR(diff) the associated relative risk. We used results reported directly as β, and as grouped levels of RR in terms of FEV₁%P and of associated measures (e.g. FEV₁/FVC).

Methods

Papers describing cohort studies involving at least three years follow-up which recorded FEV₁ at baseline and presented results relating lung cancer to FEV₁ or associated measures were sought from Medline and other sources. Data were recorded on study design and quality and, for each data block identified, on details of the results, including population characteristics, adjustment factors, lung function measure, and analysis type. Regression estimates were converted to β estimates where appropriate. For results reported by grouped levels, we used the NHANES III dataset to estimate mean FEV₁%P values for each level, regardless of the measure used, then derived β using regression analysis which accounted for non-independence of the RR estimates. Goodness-of-fit was tested by comparing observed and predicted lung cancer cases for each level. Inverse-variance weighted meta-analysis allowed derivation of overall β estimates and testing for heterogeneity by factors including sex, age, location, timing, duration, study quality, smoking adjustment, measure of FEV₁ reported, and inverse-variance weight of β.

Results

Thirty-three publications satisfying the inclusion/exclusion criteria were identified, seven being rejected as not allowing estimation of β. The remaining 26 described 22 distinct studies, from which 32 independent β estimates were derived. Goodness-of-fit was satisfactory, and exp(β), the RR increase per one unit FEV₁%P decrease, was estimated as 1.019 (95%CI 1.016-1.021). The estimates were quite consistent (I² =29.6%). Mean age was the only independent source of heterogeneity, exp(β) being higher for age <50 years (1.024, 1.020-1.028).

Conclusions

Although the source papers present results in various ways, complicating meta-analysis, they are very consistent. A decrease in FEV₁%P of 10% is associated with a 20% (95%CI 17%-23%) increase in lung cancer risk.

Association between pulmonary dysfunction as a result of occupational exposures and risk of developing cancer

BACKGROUND

Cohen's hypothesis states that pulmonary dysfunction is the underlying unifying factor that leads to numerous health risks of inhaled toxicants.

OBJECTIVE

To test the idea postulated by Cohen.

METHODS

We compiled a retrospective cohort (n = 8024) composed of participants in eight population-based research and occupational studies conducted between 1977 and 1989. Smoking history, occupational exposures, health indicators, and demographic information were obtained by questionnaire. Pulmonary function was assessed by spirometry.

RESULTS

Cox proportional hazards models were utilized to test the Cohen's hypothesis. Risk of developing cancer increased (hazard ratio, 1.31; 95% confidence interval, 1.02 to 1.67) if a subject had an obstructive pulmonary disease at baseline.

CONCLUSION

Impaired lung function caused by environmental and occupational exposures is one of the risk factors for the incidence of cancer.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Detection rate of lung cancer among chronic obstructive pulmonary disease patients regularly followed up by pulmonary physicians

BACKGROUND

  Chronic obstructive pulmonary disease (COPD) has been found to be an independent risk factor for lung cancer. The aim of this study was to evaluate whether regular follow up of COPD patients increases the diagnosis of lung cancer at an early stage.

METHODS

  Case reports of 105 male moderate to severe COPD patients who participated in a clinical study were analyzed retrospectively. Throughout the 3-year study period patients regularly visited a pulmonary physician. Investigations to detect lung cancer were ordered only with the presence of symptoms. The lung cancer incidence in the study group was compared to that of general male population matched by age.

RESULTS

  At the beginning of the study the mean age was 67 (range 55-81) years, mean smoking history 36.2 (range 11-102) years and mean forced expiratory volume in 1 s (FEV₁ ) 43.3% (range 22.7-59.7). During the study six lung cancers and five other cancers were diagnosed per 287 person-years of observation. Only one lung cancer was operable, others were locally advanced or had distant metastases.

CONCLUSIONS

  Despite the patients being followed up regularly by a pulmonary physician, most cancers were diagnosed at an advanced stage. The relative risk of getting lung cancer was 6.0 times higher (95% CI 2.7-13.3) among COPD patients than among the general population. The current study confirms that COPD patients have an increased risk of lung cancer. Moreover simple regular follow up of patients without special lung cancer screening investigations do not help to detect the cancer in its early stage. This study stresses the need to establish a more detailed follow-up program for COPD patients to detect early lung cancer in this high risk population.

Previous lung diseases and lung cancer risk: a systematic review and meta-analysis

BACKGROUND

In order to review the epidemiologic evidence concerning previous lung diseases as risk factors for lung cancer, a meta-analysis and systematic review was conducted.

METHODS

Relevant studies were identified through MEDLINE searches. Using random effects models, summary effects of specific previous conditions were evaluated separately and combined. Stratified analyses were conducted based on smoking status, gender, control sources and continent.

RESULTS

A previous history of COPD, chronic bronchitis or emphysema conferred relative risks (RR) of 2.22 (95% confidence interval (CI): 1.66, 2.97) (from 16 studies), 1.52 (95% CI: 1.25, 1.84) (from 23 studies) and 2.04 (95% CI: 1.72, 2.41) (from 20 studies), respectively, and for all these diseases combined 1.80 (95% CI: 1.60, 2.11) (from 39 studies). The RR of lung cancer for subjects with a previous history of pneumonia was 1.43 (95% CI: 1.22-1.68) (from 22 studies) and for subjects with a previous history of tuberculosis was 1.76 (95% CI=1.49, 2.08), (from 30 studies). Effects were attenuated when restricting analysis to never smokers only for COPD/emphysema/chronic bronchitis (RR=1.22, 0.97-1.53), however remained significant for pneumonia 1.36 (95% CI: 1.10, 1.69) (from 8 studies) and tuberculosis 1.90 (95% CI: 1.45, 2.50) (from 11 studies).

CONCLUSIONS

Previous lung diseases are associated with an increased risk of lung cancer with the evidence among never smokers supporting a direct relationship between previous lung diseases and lung cancer.

Incremental value of pulmonary function and sputum DNA image cytometry in lung cancer risk prediction

Lung cancer is the leading cause of cancer death worldwide. Accurate prediction of lung cancer risk is of value for individuals, clinicians, and researchers. The aims of this study were to characterize the associations between pulmonary function and sputum DNA image cytometry (SDIC) and lung cancer, and their contributions to risk prediction. During 1990 to 2007, 2,596 high-risk individuals were enrolled and followed prospectively for development of lung cancer (n = 139; median follow-up 7.7 years) in trials at the British Columbia Cancer Agency. At baseline, an epidemiologic questionnaire was administered, sputum was collected for aneuploidy measurement and spirometry was obtained. Multivariable logistic models were prepared including known lung cancer predictors (model 1), that additionally included percent-expected-forced expiratory volume in 1 second [forced expiratory volume in 1 second (FEV(1)%), model 2], and that additionally included SDIC (model 3). Prediction was assessed by evaluating discrimination (receiver operator characteristic area under the curve (ROC AUC)) and calibration. Net reclassification indices (NRI) were calculated with cutoff points for 8-year risks identifying low, intermediate, and high risk at 1.5% and 3%. Lung cancer risk increased with decline in FEV(1)%, but did so more for men than for women (interaction P < 0.001). SDIC demonstrated a dose-response with lung cancer (P = 0.022). The ROC AUCs for models 1, 2, and 3 were 0.718 (95% CI: 0.671-0.765), 0.767 (95% CI: 0.725-0.809), and 0.773 (95% CI: 0.732-0.815), respectively. Model 2 versus 1 had a NRI of 12.6% (P < 0.0001) and model 3 versus 2 had a NRI of 3.1% (P = 0.059). Spirometry and SDIC data substantially and minimally improved lung cancer prediction, respectively.

Silica exposure, smoking, silicosis and lung cancer--complex interactions

BACKGROUND

Establishing a clear relationship between workplace exposures and cancer is often difficult. The latent period for cancer development can make it difficult to establish a definite cause-effect relationship. The picture is further complicated by variable job histories, concomitant exposure to other carcinogens and other factors such as genetic susceptibility and poor nutrition. The lack of accurate and detailed record keeping may potentially mask informative differences among group of workers. Removing or reducing exposures to probable and known carcinogens, however, can prevent workplace cancer.

AIM

This paper gives an overview of the literature reporting investigations of the relationship between exposure to silica and development of lung cancer with a focus on the controversy concerning the roles of silicosis and smoking in the development of cancer.

METHOD

A literature search was conducted to identify epidemiologic papers on silica, silicosis and lung cancer using electronic databases (MEDLINE, PubMed, Web of Science) from 1996 onwards and paper bibliographies.

RESULTS

If silicosis were the necessary step leading to lung cancer, enforcing the current silica standards would protect workers against lung cancer risk as well. Alternatively, a direct silica-lung cancer association that has been suggested implies that regulatory standards should be revised accordingly.

CONCLUSION

Further research is needed in order to understand the complex pattern of interactions leading to lung cancer among silica-exposed workers (and cancers and workplace exposures in general) and to understand whether and to what extent other workplace lung carcinogens, total respirable dust and total surface size and age of silica particles affect the carcinogenic potential of silica. In addition, the apparent paradox of a lower lung cancer risk in some workplaces with high-level silica exposure needs further investigation.

Molecular characterization of chronic obstructive pulmonary disease-related non-small cell lung cancer through aberrant methylation and alterations of EGFR signaling

BACKGROUND

The aim of this study was to evaluate the molecular influence of chronic obstructive pulmonary diseases (COPD) on the pathogenesis of non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

The methylation profiles of 12 genes, and the epidermal growth factor receptor (EGFR) and KRAS mutations were determined for samples from 229 NSCLC patients. In addition, protein expression of EGFR and HER2 in 116 NSCLCs was analyzed based on the presence or absence of COPD.

RESULTS

IL-12Rbeta2 and Wif-1 methylation and HER2 overexpression were more frequent events in the COPD group. Eighty nonmalignant lung tissues had no correlation with any molecular changes between the COPD and the non-COPD group. EGFR mutation was significantly higher in the non-COPD group, while EGFR expression was inversely correlated with %FEV1.0. In the COPD group, unmethylated SPARC and sFRP-2 genes or a negative CpG island methylator phenotype (CIMP) was a negative prognostic factor, while methylation of p16(INK4A) and WNT antagonist genes was a negative prognostic factor in the non-COPD group.

CONCLUSIONS

Novel characteristics of COPD-related NSCLC were identified by examination of methylation profiles and alterations of EGFR signaling. In consideration of the high sensitivity to smoking in patients with COPD, NSCLC with COPD might be a distinct population of smoke-related NSCLC, the genetic profile of which is quite different from non-COPD NSCLC.

Chronic obstructive pulmonary disease and interstitial lung disease in patients with lung cancer

BACKGROUND AND OBJECTIVE

Although lung cancer is frequently accompanied by COPD and interstitial lung disease (ILD), the precise coincidence of these diseases with lung cancer is not well understood. The objectives of this study were to determine the prevalence of abnormal CT and spirometric findings suggestive of COPD or ILD in a population of patients with untreated lung cancer, and to estimate the lung cancer risk in this population.

METHODS

The study population consisted of 256 patients with untreated lung cancer and 947 subjects participating in a CT screening programme for lung cancer. Semi-quantitative analysis of low attenuation area (LAA), fibrosis and ground glass attenuation (GGA) on CT was performed by scoring. Gender- and age-matched subpopulations, with stratification by smoking status, were compared using the Mantel-Haenszel projection method.

RESULTS

Inter-observer consistency was excellent for LAA, but not as good for fibrosis or GGA scores. Pooled odds ratios for lung cancer risk using LAA, fibrosis, GGA scores and reduced FEV(1)/FVC and %VC were 3.63, 5.10, 2.71, 7.17 and 4.73, respectively (P < 0.0001 for all parameters). Multivariate regression analyses confirmed these results.

CONCLUSION

Abnormal CT and spirometric parameters suggestive of COPD and ILD were strong risk factors for lung cancer, even after adjusting for gender, age and smoking status.

Epithelial NF-kappaB activation promotes urethane-induced lung carcinogenesis

Chronic inflammation is linked to carcinogenesis in several organ systems. In the lungs, NF-kappaB, a central effector of inflammatory responses, is frequently activated in non-small-cell lung cancer, but its role in tumor promotion has not been studied. Several lines of evidence indicate that ethyl carbamate (urethane)-induced lung tumor formation, a prototypical mouse model of multistage lung carcinogenesis, is potentiated by inflammation. We found that mouse strains susceptible to lung tumor formation (FVB, BALB/c) exhibited early NF-kappaB activation and inflammation in the lungs after urethane treatment. However, a resistant strain (C57B6) failed to activate NF-kappaB or induce lung inflammation. In FVB mice, we identified urethane-induced NF-kappaB activation in airway epithelium, as well as type II alveolar epithelial cells and macrophages. Using an inducible transgenic mouse model (FVB strain) to express a dominant inhibitor of NF-kappaB specifically in airway epithelial cells, we found that urethane-induced lung inflammation was blocked and tumor formation was reduced by >50%. Selective NF-kappaB inhibition resulted in increased apoptosis of airway epithelial cells at 2 weeks after urethane treatment in association with a marked reduction of Bcl-2 expression. These studies indicate that NF-kappaB signaling in airway epithelium is integral to tumorigenesis in the urethane model and identify the NF-kappaB pathway as a potential target for chemoprevention of lung cancer.

Association of chronic obstructive pulmonary disease and tumor recurrence in patients with stage IA lung cancer after complete resection

BACKGROUND

Chronic obstructive pulmonary disease (COPD) poses a high risk for postoperative pulmonary complications after lung cancer surgery. We sought to determine the impact of this disease on long-term survival after surgical resection and to identify prognostic factors in pathological stage IA lung cancer.

METHODS

A retrospective chart review was completed in 442 patients with pathological stage IA lung cancer, who had a lobectomy with systematic lymph node dissection (30.3%), out of 1,461 patients who underwent lung cancer surgery at our hospital from January 1990 to April 2005. The functional definition of COPD, according to the spirometric guidelines of the Global Initiative for Chronic Obstructive Lung Disease, was forced expiratory volume in 1 second to forced vital capacity less than 70% (FEV1/FVC). The postoperative complications were compared between the non-COPD (362 patients) and COPD (80 patients) groups. Overall survival and disease-free survival were analyzed using the Kaplan-Meier method and log-rank test. Prognostic factors were identified by univariate and multivariate analyses.

RESULTS

The frequencies of all pulmonary complications except for pneumonia and tracheostomy were similar between the two groups. Overall survival and disease-free survival in the COPD group were significantly worse than those in the non-COPD group (p < 0.0001 and p = 0.037, respectively). Significant prognostic factors were larger tumor size (p = 0.0035) and COPD (p = 0.0147). Significant risk factors for cancer recurrence were larger tumor size (p = 0.001) and COPD (p = 0.0105) by multivariate analyses.

CONCLUSIONS

Patients with COPD had poorer long-term survival. This may be due to a higher incidence of tumor recurrence.

Nonsteroidal anti-inflammatory drugs and lung cancer risk: a population-based case control study

BACKGROUND

It remains unknown whether nonsteroidal anti-inflammatory drugs (NSAIDs) confer a protective effect against lung cancer development. We examined the relationship between NSAID exposure and subsequent lung cancer development in a large statewide, population-based cohort.

DESIGN

Nested case-control study in the Tennessee Medicaid population from 1990 to 2000.

METHODS

Lung cancer cases were identified using a statewide computerized claims database. Each time a case was identified, age- and sex-matched controls were randomly selected from the available source population. A detailed pharmacy database quantified nonsteroidal anti-inflammatory drug (NSAID) exposure during the 5 years before cancer diagnosis, and conditional logistic regression was used to examine the relationship between NSAID exposure and lung cancer development. Identical analyses were repeated in a subpopulation of high-risk individuals with chronic obstructive pulmonary disease (COPD).

RESULTS

303,399 persons were enrolled in the study population. During 1.9 million person-years of follow-up (median 6.3 years per person), 3,370 lung cancer cases were identified. Among those ever using NSAIDs, the adjusted odds ratio of developing lung cancer was 1.03 (95% confidence interval: 0.94-1.12). Among those using >24 months of NSAIDs in the 5 years before lung cancer diagnosis, the adjusted odds ratio for lung cancer was 0.96 (95% confidence interval: 0.82-1.11), and no protective effect was demonstrated in any NSAID exposure stratum. Similarly, among the 2519 high-risk individuals with chronic obstructive pulmonary disease, no significant protective effect from NSAIDs was noted.

CONCLUSION

This large statewide, population-based study did not demonstrate a protective effect of NSAIDs on lung cancer development in either the general or high-risk chronic obstructive pulmonary disease populations.

The value of forced expiratory volume in 1 second decline in the assessment of chronic obstructive pulmonary disease progression

Forced expiratory volume in 1 second (FEV1) declines normally with aging by approximately 30 mL/yr, but in susceptible smokers, the decline is greater (about 60 mL/yr), resulting in the development of chronic obstructive pulmonary disease (COPD). Smoking cessation usually restores the normal or near-normal rate of FEV1 decline, whereas intermittent quitting provides less benefit. Thus, smoking cessation is a critical component for the prevention of COPD progression. FEV1 is central to the definition of COPD and classification of its severity. FEV1 is a good predictor of exercise tolerance and correlates with survival and quality of life. More rapid FEV1 decline is also predictive of morbidity, mortality, and hospitalization rates. Risk factors for accelerated decline in FEV1, in addition to smoking, include frequent exacerbations, airways reactivity, and possibly chronic systemic inflammation. Genetic components of the decline in FEV1 are being actively explored, but none has been extensively validated other than alpha1-antitrypsin deficiency. To date, only smoking cessation has been definitively shown to be effective in reducing the rate of FEV1 decline, but other therapeutic strategies are under active research. Consequently, FEV1 and its change over time are important outcomes in COPD and valuable measures for the assessment of disease progression.

Impaired lung function and lung cancer incidence in a cohort of Swedish construction workers

BACKGROUND

Although impaired lung function in general has been associated with an increased risk of lung cancer, past studies typically have not attempted to investigate separately the obstructive and restrictive components of respiratory impairment. To deal with this question further, data from a large (n = 176 997) cohort of male Swedish construction workers, for whom spirometry measurements before follow-up were available, were analysed.

METHODS

Cancer incidence for 1971-2001 was obtained through linkage with the national cancer registry. Using a modification of the Global Initiative for Chronic Obstructive Lung Disease criteria for chronic obstructive pulmonary disease (COPD), subjects were classified into five categories of lung function: normal, mild COPD, moderate COPD, severe COPD and restrictive lung disease (RLD). Rate ratios (RR) and 95% confidence intervals (CI) for lung cancer across lung function categories were calculated using Poisson regression, adjusted for age and smoking. Other end points (histological types of lung cancer, non-lung tobacco-related cancers, other cancers, total mortality) were also investigated.

RESULTS

834 incident cases of lung cancer were identified. Increased rates of lung cancer were observed for both COPD (mild: RR 1.5, 95% CI 1.2 to 1.9; moderate/severe: RR 2.2, 95% CI 1.8 to 2.7) and RLD (RR 2.0, 95% CI 1.6 to 2.5) relative to normal lung function. These associations did not meaningfully change on applying follow-up lag times of 5, 10 and 15 years after spirometry. When analysed by histological type, associations with both COPD and RLD were stronger for squamous cell carcinoma and small cell carcinoma, and weaker for adenocarcinoma. Both COPD and RLD were associated with increased rates of total mortality.

CONCLUSIONS

Obstructive and restrictive impairments in lung function are associated with increased lung cancer risk.

Prevalence of COPD in Women Compared to Men Around the Time of Diagnosis of Primary Lung Cancer

PURPOSES

COPD is a well-known independent risk factor that is associated with primary lung cancer. There is, however, a striking paucity of women in studies demonstrating this association. The purpose of this study was to compare the prevalence of COPD as determined by pulmonary function tests (PFTs) between women and men at around the time of lung cancer diagnosis.

METHODS

We retrospectively reviewed patients with newly diagnosed primary lung cancer who had undergone PFTs prior to their treatment. The diagnosis of airflow obstruction was made according to American Thoracic Society guidelines. Comparisons of the prevalence of COPD between men and women were performed using univariate and multivariate logistic regression analysis.

RESULTS

Of the 294 patients in the study, 151 patients (51.4%) were men and 143 patient (48.6%) were women. Of the men, 110 patients (72.8%) had COPD compared with 75 patients (52.5%) among the women. This represented a significantly lower prevalence of COPD in women than in men (odds ratio [OR], 0.41; 95% confidence interval [CI], 0.25 to 0.67; p = 0.0003). When adjusted for age and smoking status, a sustained lower prevalence of COPD was noted in women compared to men (OR, 0.44; 95% CI, 0.26 to 0.74; p = 0.002). In a subset of 256 smokers, there remained a lower prevalence of COPD in women compared to men (OR, 0.45; 95% CI, 0.27 to 0.77; p = 0.003). Adjusted analysis to control for age and number of pack-years of smoking in this subset again showed a sustained reduction in the OR for women presenting with COPD (OR, 0.48; 95% CI, 0.28 to 0.83; p = 0.009).

CONCLUSIONS

When COPD was examined as an end point among patients who had newly diagnosed lung cancer, a significantly higher proportion of women had normal PFT results. Gender-based differences on PFT results should be considered during the screening of lung cancer, because the stratification of high-risk patients based on the presence of COPD may miss a significant proportion of women with lung cancer.

Tobacco harm reduction strategies: The case for physical activity

Since the effects of tobacco smoke are so detrimental to health, growing consideration has been given to the development of harm reduction strategies for those smokers who are unable or unwilling to stop using tobacco. The term harm reduction refers to a policy, strategy, or particular intervention that assumes continued use of an undesired behavior and aspires to lower the risk of adverse consequences associated with the continuation of this addictive behavior. Up to this point, tobacco harm reduction interventions have focused on reducing tobacco-related harm through the utilization of innovative tobacco products, reduced tobacco consumption, and pharmaceutical medications. With the possible exception of medicinal nicotine products, these strategies remain unproven and thus far no scientific or medical literature exists to suggest these harm reduction strategies reduce tobacco-related exposure, morbidity, or mortality. Consequently, a need exists for broadening the range of potentially effective harm reduction strategies. This preliminary review suggests that physical activity has the potential to become one such strategy. Of the eight principles that characterize a harm reduction strategy, all are at least partially satisfied by physical activity. Further, emerging evidence indicates that physical activity may delay the occurrence of disease and premature death initiated by tobacco consumption. Significant concerns remain regarding the practicality of physical activity as a harm reduction strategy and the extent to which participation in physical activity may be used to justify continued smoking.

Relationship between reduced forced expiratory volume in one second and the risk of lung cancer: a systematic review and meta-analysis

BACKGROUND

Individuals with severely impaired lung function have an increased risk of lung cancer. Whether milder reductions in forced expiratory volume in 1 second (FEV(1)) also increase the risk of lung cancer is controversial. Moreover, there is little consensus on whether men and women have similar risks for lung cancer for similar decreases in FEV(1).

METHODS

A search was conducted of PubMed and EMBASE from January 1966 to January 2005 and studies that examined the relationship between FEV1 and lung cancer were identified. The search was limited to studies that were population based, employed a prospective design, were large in size (> or = 5000 participants), and adjusted for cigarette smoking status.

RESULTS

Twenty eight abstracts were identified, six of which did not report FEV1 and eight did not adjust for smoking. Included in this report are four studies that reported FEV1 in quintiles. The risk of lung cancer increased with decreasing FEV1. Compared with the highest quintile of FEV1 (> 100% of predicted), the lowest quintile of FEV1 (< approximately 70% of predicted) was associated with a 2.23 fold (95% confidence interval (CI) 1.73 to 2.86) increase in the risk for lung cancer in men and a 3.97 fold increase in women (95% CI 1.93 to 8.25). Even relatively small decrements in FEV1 ( approximately 90% of predicted) increased the risk for lung cancer by 30% in men (95% CI 1.05 to 1.62) and 2.64 fold in women (95% CI 1.30 to 5.31).

CONCLUSION

Reduced FEV1 is strongly associated with lung cancer. Even a relatively modest reduction in FEV1 is a significant predictor of lung cancer, especially among women.

ADVANCES IN CANCER EPIDEMIOLOGY: Understanding Causal Mechanisms and the Evidence for Implementing Interventions

In a worldwide population of 6 billion, in the year 2000, approximately 10 million cancers were diagnosed, and there were an estimated 6.2 million cancer deaths. Whereas the universality of cancer incidence and mortality is established, the burden of cancer by type or organ site is distributed unequally between developing and industrialized nations. Populations in developing countries are disproportionately affected by cancers in which infectious agents are causal. Our review of advances in cancer epidemiology underscores the complexity of pathogenic mechanisms mediated by chronic inflammation, obesity, and gene-environment interactions as in tobacco and alcohol carcinogenesis. Ultimately, the implementation of effective cancer control interventions that will serve to alleviate the cancer burden must integrate basic and applied research in the behavioral, social, biomedical, and population sciences.

Genetic polymorphisms and environmental risk of lung cancer: a review

Lung cancer results from man-made and natural environmental exposures acting in concert with both genetic and acquired characteristics. Chronic inhalation of cigarette smoke is a major risk factor, and environmental tobacco exposure can cause lung cancer in life-long neversmokers. Air pollution, indoor-radon exposure, occupational exposures, dietary, physical activity, and reproductive history have been identified as independent or contributing risk factors for lung cancer. Because only a small portion of smokers develops the disease, genetic susceptibility can contribute to the risk. Developments in molecular biology have led to the discovery of biological markers that increase predisposition to lung carcinogenesis. Therefore, the high-risk genotype of an individual can be determined easily. Because of the great number of carcinogen-activating and -detoxifying enzymes, the variation in their expression, the complexity of exposures to tobacco carcinogens, and the existence of multiple alleles at loci of those enzymes results in differential susceptibilities of individuals. As lung cancer is a multifactorial disease, an improved understanding of the interplay of environmental and genetic polymorphisms at multiple loci can help identify individuals who are at increased risk for lung cancer. Hopefully, in the future we will be able to screen for lung cancer susceptibility by using specific biomarkers.

Pulmonary function as a predictor of lung cancer mortality in continuing cigarette smokers and in quitters

BACKGROUND

Forced expiratory volume in 1 second (FEV(1)) may be useful for identifying smokers at higher risk of lung cancer. We examined the association of FEV(1) with lung cancer mortality (LCM) among cigarette smokers in the Multiple Risk Factor Intervention Trial (MRFIT).

METHODS

In all, 6613 MRFIT baseline smokers alive at trial end in 1982 had acceptable FEV(1) measures and complete smoking history; men were classified as during-trial long-term quitters (N = 1292), intermittent quitters (1961), and never quitters (3360). Proportional hazards models for LCM were fit with quintiles of average FEV(1), adjusted for age, height, race, smoking history, and other risk factors.

RESULTS

For long-term, intermittent, and never quitters respectively, mean baseline cigarettes/ day was 28, 32, and 35; trial-averaged FEV(1) was 3201, 3146, and 3082 ml; and average decline in FEV(1) was -46.0, -54.6, and -62.5 ml/year. With median post-trial mortality follow-up of 18 years, there were 363 lung cancer deaths. Age-adjusted LCM rates varied across FEV(1) quintiles from 50 (lowest quintile) to 11 (highest quintile), 58 to 11, and 76 to 20, per 10 000 person-years, for long-term quitters, intermittent quitters, and never quitters, respectively. Multivariate adjusted hazard ratios for 100 ml higher FEV(1) were 0.92 [P = 0.004], 0.95 [P = 0.003], and 0.95 [P < 0.0001] respectively.

CONCLUSIONS

These results demonstrate the strong predictive value of FEV(1) for lung cancer among cigarette smokers independent of smoking history; results did not differ by during-trial quit status. FEV(1) may be a biological marker for smoking dose or it may be that genetic susceptibilities to both decreased FEV(1) and lung cancer are associated.

Comorbidity in operable lung cancer: a multicenter descriptive study on 2992 patients

STUDY OBJECTIVES

To ascertain the frequency of diseases associated (comorbidity) with operable lung cancer (LC) globally, in relation to the presence of neoplastic clinical symptoms and age.

DESIGN

Prospective; multi-institutional of 19 Spanish hospitals.

PATIENTS

Two thousand nine hundred and ninety two consecutive cases of LC, treated surgically by the Bronchogenic Carcinoma Co-operative Group of the Spanish Society of Pneumology and Thoracic Surgery (GCCB-S) between 1993 and 1997, are analysed.

METHODS

At time of treatment, data on the presence or absence of different specific comorbidities in all consecutive patients operated on for LC were entered on identical forms at all hospitals of the GCCB-S.

RESULTS

In 2189 patients (73%) there was one or several comorbidities (chronic obstructive pulmonary disease [COPD], systemic arterial hypertension, previous tumour, cardiac disease, peripheral vascular disease or diabetes). Fifty percent of the LC was associated to COPD; in 32% of these patients with COPD, preoperative measurement of FEV1 was 70% below the theoretical value. In comparing the cases with symptoms ascribable to LC, it was found that in asymptomatic patients the presence of a previous tumour, arterial hypertension or cardiac disease was significantly more frequent. Conversely, in symptomatic patients, COPD was significantly more frequent. The frequency of all evaluated comorbidities is significantly higher in the older age groups.

CONCLUSIONS

In this multicenter study encompassing 2992 patients with operable LC, a high frequency of comorbidity has been found, COPD occurring most frequently. Certain diseases are more prevalent in asymptomatic patients, probably due to a screening bias. In older patients, there was a significant increase of all comorbidities.

Mortality from lung cancer among silicotic patients in Sardinia: an update study with 10 more years of follow up

OBJECTIVES

To evaluate the association between silica, silicosis and lung cancer, the mortality of 724 patients with silicosis, first diagnosed by standard chest x ray film between 1964 and 1970, has been analysed by a cohort study extended to 31 December 1997.

METHODS

Smoking and detailed occupational histories were available for each member of the cohort as well as the estimated lifetime exposure to respirable silica dust and radon daughters. Two independent readers blindly classified standard radiographs according to the 12 point International Labour Organisation (ILO) scale. Lung function tests meeting the American Thoracic Society's criteria were available for 665 patients. Standardised mortality ratios (SMRs) for selected causes of death were based on the age specific Sardinian regional death rates.

RESULTS

The mortality for all causes was significantly higher than expected (SMR 1.35, 95% confidence interval (95% CI) 1.24 to 1.46) mainly due to tuberculosis (SMR 22.0) and to non-malignant chronic respiratory diseases (NMCRD) (SMR 6.03). All cancer deaths were within the expected numbers (SMR 0.93; 95% CI 0.76 to 1.14). The SMR for lung cancer was 1.37 (95% CI 0.98 to 1.91, 34 observed), increasing to 1.65 (95% CI 0.98 to 2.77) allowing for 20 years of latency since the first diagnosis of silicosis. Although mortality from NMCRD was strongly associated to the severity of radiological silicosis and to the extent of the cumulative exposure to silica, SMR for lung cancer was weakly related to the ILO categories and to the cumulative exposure to silica dust only after 20 years of lag interval. A significant excess of deaths from lung cancer (SMR 2.35) was found among silicotic patients previously employed in underground metal mines characterised by a relatively high airborne concentration of radon daughters and among ever smokers who showed an airflow obstruction at the time of the first diagnosis of silicosis (SMR 3.29). Mortality for lung cancer related to exposure was evaluated with both the Cox's proportional hazards modelling within the entire cohort and a nested case-control study (34 cases of lung cancer and 136 matched controls). Both multivariate analyses did not show any significant association with cumulative exposure to silica or severity of silicosis, but confirmed the association between mortality for lung cancer and relatively high exposure to radon, smoking, and airflow obstruction as significant covariates.

CONCLUSIONS

The findings indicate that the slightly increased mortality for lung cancer in this cohort of silicotic patients was significantly associated with other risk factors-such as cigarette smoking, airflow obstruction, and estimated exposure to radon daughters in underground mines-rather than to the severity of radiological silicosis or to the cumulative exposure to crystalline silica dust itself.

Influence of age and predicted forced expiratory volume in 1 s on prognosis following complete resection for non-small cell lung carcinoma

OBJECTIVE

To evaluate age of the patient at the time of surgery and estimated postoperative forced expiratory volume in 1 s (FEV1%) as predictors of long-term survival following complete resection of non-small cell lung carcinoma (NSCLC).

METHODS

Retrospective, observational study. Records of patients operated on for NSCLC between January 1994 and December 1997 were reviewed. One hundred and ninety three patients who underwent complete pathological resection and survived surgery were included for study. Patients were divided in groups depending on age at the time of surgery and predicted postoperative FEV1% calculated according to the number of resected segments. Values of the 75th percentile of age (70.29 years) and 50th percentile of predicted FEV1% (52.9) were the cut-points selected for group division. To increase the power of the analysis pathological staging was also converted in a binary variable and resumed to localized (stage I) or extended (stage II-IIIB). Univariate analysis of the effect of each variable on survival was assessed by Kaplan-Meier method and log-rank test. Relationship between variables was investigated using 2x2 tables and Fisher's exact test. Unrelated variables (extension, age and low estimated postoperative FEV1%) entered in a Cox-regression model to predict long-term survival following resection.

RESULTS

Pathological stage (P<0.0001), age (P=0.01) and low estimated postoperative FEV1% (P=0.0007) showed independent value to predict the outcome.

CONCLUSION

Advanced age and low predicted postoperative FEV1% play an adverse effect on survival of completely resected NSCLC.

Genetic analysis of families with nonsmoking lung cancer probands

As part of a genetic epidemiologic study of lung cancer among nonsmokers, we investigated the role of genetic predisposition in familial aggregation. Cases were identified from the Metropolitan Detroit Cancer Surveillance System. Information on lung cancer occurrence, smoking habits (active or passive), and chronic respiratory diseases in first-degree relatives was obtained for 257 nonsmoking lung cancer probands (71 males, 186 females) diagnosed at ages 40-84 years. Among the 2,021 first-degree relatives, 24 (2.6%) males and 10 (1.1%) females were reported as having lung cancer. The occurrence of lung cancer among smoking and nonsmoking relatives was 4.5% and 1.1% in males and 2.8% and 0.4% in females, respectively. To evaluate the role of a putative Mendelian gene (one locus, two alleles) in the presence of other risk factors, we performed complex segregation analyses on the data using two different regressive model approaches [Segregation Analysis of a Discrete Trait Under a Class A Regressive Logistic Model, V4.0 (REGD) and Segregation Analysis of a Truncated Trait, V2.0, Model 1(REGTL)] as implemented in the Statistical Analysis for Genetic Epidemiology (SAGE) program. Using either approach, an environmental model best explained the observed lung cancer aggregation in families ascertained through nonsmoking probands. Based on our final model, only 0.04% of this population had a very high risk and 4.2% had a moderate risk of lung cancer. The rest of the population had virtually no risk of lung cancer during their lifetime unless they have multiple risk factors. Among the high-risk individuals without any risk factor under study, the estimated risks at ages 40, 60, and 80 years in males were 16.7%, 83.6%, and 95.4%, and in females were 14.0%, 72.2%, and 88.0%, respectively. Among at-moderate-risk smokers the estimated risks at the same age and gender groups were essentially the same as in the high-risk nonsmokers. Our results suggest that the pattern of lung cancer occurrence in families of nonsmoking lung cancer patients differs from that in families of smoking lung cancer patients. Despite the profound effect of smoking on the risk of lung cancer, other environmental and/or genetic risk factors need to be identified.

The prevalence of COPD: using smoking rates to estimate disease frequency in the general population

STUDY OBJECTIVES

To develop and validate a model based on smoking rates that will provide reliable estimates of the true prevalence of COPD that include both clinically detected and undetected patients.

DESIGN

Model based on literature review. Age- and gender-specific rates of lung impairment by smoking status were applied to US smoking data. Resultant estimates were compared to the actual prevalence of obstructive airway disease as estimated by US national surveys. The model then was applied to estimate the prevalence of COPD in several European countries, where national data on undiagnosed lung disease do not exist.

SETTING

The model was adapted from both a literature review and health-care data, and the analysis was applied to the United States and Europe.

RESULTS

Using smoking rates, we estimate from our model that 15.3 million people who are > 40 years of age in the United States have COPD. The prevalence estimate, based on spirometric definitions for COPD in the same age group using the Third National Health and Nutrition Examination Survey (NHANES III), is 17.1 million people. NHANES III and other US national health-care surveys further suggest that only between 2.4 and 7 million people actually have COPD diagnosed; thus, the proportion of COPD that is currently being diagnosed in the United States is between 14% and 46% of all cases. Using smoking rates and our model, which was developed and validated for the United States, we calculated the prevalence of COPD for Germany (2.7 million people), the United Kingdom (3.0 million people), Spain (1.5 million people), Italy (2.6 million people), and France (2.6 million people) in those people > 45 years of age.

CONCLUSIONS

Smoking rates appear to provide a useful method of estimating current COPD prevalence in those countries where more objective data are unavailable. These results are important because recognition of the true burden of disease and corresponding efforts to increase early identification of COPD can help to reduce the morbidity and mortality associated with COPD in populations at risk.

Office spirometry for lung health assessment in adults: A consensus statement from the National Lung Health Education Program

COPD is easily detected in its preclinical phase using spirometry, and successful smoking cessation (a cost-effective intervention) prevents further disease progression. This consensus statement recommends the widespread use of office spirometry by primary-care providers for patients >/= 45 years old who smoke cigarettes. Discussion of the spirometry results with current smokers should be accompanied by strong advice to quit smoking and referral to local smoking cessation resources. Spirometry also is recommended for patients with respiratory symptoms such as chronic cough, episodic wheezing, and exertional dyspnea in order to detect airways obstruction due to asthma or COPD. Although diagnostic-quality spirometry may be used to detect COPD, we recommend the development, validation, and implementation of a new type of spirometry-office spirometry-for this purpose in the primary-care setting. In order to encourage the widespread use of office spirometers, their specifications differ somewhat from those for diagnostic spirometers, allowing lower instrument cost, smaller size, less effort to perform the test, improved ease of calibration checks, and an improved quality-assurance program.

Race and gender differences in the effects of smoking on lung function

STUDY OBJECTIVE

To assess the extent to which the relationship between smoking and lung function in adults varies by gender and race/ethnicity.

DESIGN

A random-effects metaregression analysis to synthesize results from common cross-sectional regression models fit to participants in each of 10 gender-race strata in each of eight large population-based observational studies or clinical trials.

SETTING

Source data collected as part of the most recently completed examination cycle for each of the participating studies.

PARTICIPANTS

Participants ranged in age from 30 to 85 years, although the age, race, gender, and general health characteristics of each of the populations varied greatly.

INTERVENTIONS

Most of the studies were observational in nature, although some did involve lifestyle interventions. All treatment assignments were ignored in the analysis.

MEASUREMENTS AND RESULTS

All studies measured lung function using standardized methods with centrally trained and certified technicians. Study findings confirm statistically significant, dose-related smoking effects in all race-gender groups studied. Significant gender differences in the effects of cigarette smoking were seen only for blacks; black men who smoked had greater smoking-related declines in FEV(1) than did black women. This effect was present in only one of two smoking models, however. Significant racial differences in the effects of smoking were seen only for men, with Asian/Pacific Islanders having smaller smoking-related declines than white men in both models.

CONCLUSIONS

In summary, this analysis generally failed to support the hypothesis of widespread differences in the effects of cigarette smoking on lung function between gender or racial subgroups.

The adverse health effects of tobacco and tobacco-related products

Tobacco use continues to occur in epidemic proportions and with it, significant morbidity and mortality. One third of smokers will die prematurely of a smoking-related disease. This article reviews the adverse health effects of tobacco use so that clinicians can be aware of the benefits patients will reap when they stop using this lethal substance.

Spirometry in primary care practice: the importance of quality assurance and the impact of spirometry workshops

OBJECTIVE

To determine the quality of spirometry performed in primary care practice and to assess the impact of formal training.

DESIGN

Randomized, controlled prospective interventional study.

SETTING

Primary care practice, Auckland City, New Zealand.

PARTICIPANTS

Thirty randomly selected primary care practices randomized to "trained" or "usual" groups. One doctor and one practice nurse were nominated to participate from each practice.

INTERVENTIONS

"Trained" was defined as participation in an "initial" spirometry workshop at week 0 and a "maintenance of standards" workshop at week 12. "Usual" was defined as no formal training until week 12, when participants they attended the same "initial" workshop provided for the trained group. The study duration was 16 weeks. Each practice was provided with a spirometer to be used at their clinical discretion.

MEASUREMENTS AND RESULTS

Spirometry data were uploaded weekly and analyzed using American Thoracic Society (ATS) criteria for acceptability and reproducibility. The workshops were assessed objectively with practical and written assessments, confirming a significant training effect. However, analysis of spirometry performed in clinical practice by the trained practitioners revealed three acceptable blows in only 18.9% of patient tests. In comparison, 5.1% of patient tests performed by the usual practitioners had three acceptable blows (p<0.0001). Only 13.5% of patient tests in the trained group and 3.4% in the usual group (p<0.0001) satisfied full acceptability and reproducibility criteria. However, 33.1% and 12.5% of patient tests in the trained and usual groups, respectively (p<0.0001), achieved at least two acceptable blows, the minimum requirement. Nonacceptability was largely ascribable to failure to satisfy end-of-test criteria; a blow of at least 6 s. Visual inspection of the results of these blows as registered on the spirometer for the presence of a plateau on the volume-time curve suggests that < 15% were acceptable.

CONCLUSIONS

Although a significant training effect was demonstrated, the quality of the spirometry performed in clinical practice did not generally satisfy full ATS criteria for acceptability and reproducibility. Further study would be required to determine the clinical impact. However, the ATS guidelines allow for the use of data from unacceptable or nonreproducible maneuvers at the discretion of the interpreter. Since most of the failures were end-of-test related, the FEV1 levels are likely to be valid. Our results serve to emphasize the importance of effective training and quality assurance programs to the provision of successful spirometry in primary care practice.