Lung cancer risk and do-it-yourself activities. A neglected risk factor for lung cancer.

BACKGROUND: The aim of this study was to assess the relationship between do-it-yourself activities entailing the exposure to carcinogenic substances and the risk of lung cancer. METHODS: We pooled individual data from different case-control studies conducted in Northwestern Spain which investigated residential radon and lung cancer. Cases had an anatomopathologically confirmed primary lung cancer and controls were selected at the pre-surgery unit with uncomplicated surgeries. Both cases and controls were older than 30 years with no previous cancer history. All participants were interviewed face-to-face using a specific questionnaire. Painting, model building, furniture refinishing and woodworking or home carpentry were the do-it-yourself activities considered risky due to exposure to carcinogenic agents. RESULTS: We included 1528 cases and 1457 controls. Practicing do-it-yourself risk activities was more frequent among cases: 16.0% were exposed to carcinogenic exposures during leisure time, compared to 11.8% for controls. The overall adjusted OR for lung cancer risk among individuals who practiced do-it-yourself risk activities, was 1.77 (95% CI: 1.36-2.31); this was 2.17 (95% CI: 1.51-3.11) when the analysis was restricted to individuals who performed these activities for at least 10 years. These risks were greater when the analyses were carried out exclusively among never-smokers, with the respective ORs being 2.04 (95% CI: 1.38-3.01) and 3.10 (95% CI: 1.78-5.40). CONCLUSION: These results support the hypothesis that do-it-yourself activities involving exposure to certain carcinogens are associated with an increased risk of lung cancer, both in ever and never-smokers.

Lung cancer and residential radon in never-smokers: A pooling study in the Northwest of Spain.

BACKGROUND: Using a pooled case-control study design, including only never-smokers, we have assessed the association of residential radon exposure with the subsequent occurrence of lung cancer. We also investigated whether residential radon poses a different risk specifically for adenocarcinoma. METHODS: We pooled individual data from different case-control studies conducted in recent years in Northwestern Spain which investigated residential radon and lung cancer. All participants were never-smokers. Cases had a confirmed biopsy of primary lung cancer. Hospital controls were selected at pre-surgery units, presenting for non-complex surgical procedures. They were interviewed using a standardized instrument. Residential radon was measured using alpha track detectors at the Galician Radon Laboratory at the University of Santiago de Compostela. RESULTS: A total of 1415 individuals, 523 cases and 892 controls were included. We observed an odds ratio of 1.73 (95%CI: 1.27-2.35) for individuals exposed to ≥ 200 Bq/m3 compared with those exposed to ≤100 Bq/m3. Lung cancer risk for adenocarcinoma was 1.52 (95%CI: 1.14-2.02) using the same categories for radon exposure. CONCLUSIONS: Residential radon is a clear risk factor for lung cancer in never-smokers. Our data suggest that radon exposure is associated with all histological types of lung cancer and also with adenocarcinoma, which is currently the most frequent histological type for this disease.

Chronic Obstructive Pulmonary Disease in Lung Cancer Patients: Prevalence, Underdiagnosis, and Clinical Characterization.

BACKGROUND: Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) are associated with increased morbidity and mortality. The differential clinical and functional features among LC patients with or without COPD have not been defined. OBJECTIVES: The aims of this study were to examine the prevalence and underdiagnosis rate of COPD in LC patients and to compare the clinical and functional features of LC patients with and without COPD. METHODS: We designed a multicenter hospital-based study including all LC cases diagnosed from January 2014 to August 2016. We assessed epidemiological, clinical, radiological, functional, and histological variables in all cases. RESULTS: We recruited 602 patients with LC, most of them men (77.9%), with a median age of 67 ± 15 years. The COPD prevalence among LC patients was 51.5%, with a underdiagnosis rate of 71.6%. The LC+COPD patients were older and the proportion of men was higher compared with the LC-only patients. The LC+COPD patients had more pack-years, more squamous LC, a lower monoxide transfer coefficient (KCO), and higher Charlson index scores than patients with LC only. The median survival of LC-only patients was 37% longer than that of LC+COPD patients (22 vs. 16 months), but this difference was not statistically significant. CONCLUSIONS: Among LC patients, COPD is prevalent and underdiagnosed. Patients with LC+COPD more often have squamous LC, have greater comorbidities, and have a lower KCO. More effort should be made for an early diagnosis of COPD to select patients at higher risk of developing LC.

Alcohol consumption and lung cancer risk in never smokers: a pooled analysis of case-control studies.

Background: Lung cancer is the deadliest cancer in developed countries but the etiology of lung cancer risk in never smokers (LCRINS) is largely unknown. We aim to assess the effects of alcohol consumption, in its different forms, on LCRINS. Methods: We pooled six multi-center case-control studies developed in the northwest of Spain. Cases and controls groups were composed of never smokers. We selected incident cases with anatomopathologically confirmed lung cancer diagnoses. All participants were personally interviewed. We performed two groups of statistical models, applying unconditional logistic regression with generalized additive models. One considered the effect of alcohol type consumption and the other considered the quantity of each alcoholic beverage consumed. Results: A total of 438 cases and 863 controls were included. Median age was 71 and 66, years, respectively. Adenocarcinoma was the predominant histological type, comprising 66% of all cases. We found that any type of wine consumption posed an OR of 2.20 OR 95%CI 1.12-4.35), and spirits consumption had an OR of 1.90 (95%CI 1.13-3.23). Beer consumption had an OR of 1.33 (95%CI 0.82-2.14). These results were similar when women were analyzed separately, but for men there was no apparent risk for any alcoholic beverage. The dose-response analysis for each alcoholic beverage revealed no clear pattern. Conclusions: Wine and spirits consumption might increase the risk of LCRINSs, particularly in females. These results have to be taken with caution given the limitations of the present study.

Residential radon, EGFR mutations and ALK alterations in never-smoking lung cancer cases.

The aim of this study was to assess if residential radon exposure might cause EGFR mutations or ALK rearrangements in never-smokers.We designed a multicentre case-control study in a radon-prone area (Galicia, Spain); only lung cancer cases were included in the study. We obtained residential radon measurements and clinical information for all the participants. We compared the median values of residential radon between patients with EGFR mutations or ALK rearrangements versus those without them.323 patients were included. Median age was 70 years and 19.5% were males. 42 and 15% of patients were EGFR- and ALK-positive, respectively. The most frequent EGFR alterations were exon 19 deletions and exon 21 (L858R) single-point substitution mutations. ALK-positive patients were 10 years younger than ALK-negative patients. Residential radon levels were two-fold higher in patients with exon 19 deletions compared with patients with exon 21 (L858R) single-point substitution mutations (216 versus 118 Bq·m-3; p=0.057). There were no differences in residential radon levels by EGFR mutation status. ALK-positive patients (n=12) essentially had two-fold residential radon levels compared with ALK-negative patients (290 versus 164 Bq·m-3, respectively).Residential radon may have a role in the molecular signature of lung cancer in never-smokers, although more studies with larger sample sizes are needed to support this hypothesis.

Small cell lung cancer in never-smokers.

Our aim was to describe the characteristics of a case-series of never-smoker small cell lung cancer (SCLC) cases.Cases of SCLC were selected from a prospective, multicenter, hospital-based case-control study performed in Spain. Participants were never-smokers older than 30 years with an anatomo-pathological confirmation of primary lung cancer. We collected clinical and epidemiological variables according to the study's protocol.We included 19 SCLC cases, 18 females (94.7%), median age 75 years (interquartile range (IQR) 70-80 years). Median residential radon concentration was 195 Bq·m(-3) (IQR 130-229 Bq·m(-3)). 10 patients had limited disease and nine had extended disease. Median survival was 242 days (IQR 94-496 days); 1- and 2-year survival were 36.8% and 17.6%, respectively. Survival was much higher for individuals with limited disease than for those with extended disease (median 336 versus 235 days; 1-year survival 50% versus 22.2% and 2-year survival 27% versus 0%, respectively). Performance status at diagnosis was closely related to survival.SCLC is an infrequent, highly aggressive disease in never-smokers. Survival is poor, even for limited disease. Age at diagnosis in SCLC is higher than that observed for never-smokers with adenocarcinoma. Residential radon exposure is higher than the action levels recommended by the World Health Organization.

Lung cancer in never-smokers: a case-control study in a radon-prone area (Galicia, Spain).

The aim of the study was to assess the effect of residential radon exposure on the risk of lung cancer in never-smokers and to ascertain if environmental tobacco smoke modifies the effect of residential radon. We designed a multicentre hospital-based case-control study in a radon-prone area (Galicia, Spain). All participants were never-smokers. Cases had an anatomopathologically confirmed primary lung cancer and controls were recruited from individuals undergoing minor, non-oncological surgery. Residential radon was measured using alpha track detectors. We included 521 individuals, 192 cases and 329 controls, 21% were males. We observed an odds ratio of 2.42 (95% CI 1.45-4.06) for individuals exposed to ≥200 Bq·m(-3) compared with those exposed to <100 Bq·m(-3). Environmental tobacco smoke exposure at home increased lung cancer risk in individuals with radon exposure>200 Bq·m(-3). Individuals exposed to environmental tobacco smoke and to radon concentrations>200 Bq·m(-3) had higher lung cancer risk than those exposed to lower radon concentrations and exposed to environmental tobacco smoke. Residential radon increases lung cancer risk in never-smokers. An association between residential radon exposure and environmental tobacco smoke on the risk of lung cancer might exist.

Fruit and vegetable consumption and lung cancer risk: a case-control study in Galicia, Spain.

Lung cancer has multiple risk factors and tobacco is the main one. Diet plays a role, but no clear effect has been consistently observed for different fruit and vegetable consumption. We aim to assess the association between fruit and vegetable consumption and lung cancer risk through a hospital-based case-control study in Spanish population. We recruited incident lung cancer cases in 2 Spanish hospitals from 2004 to 2008. Controls were individuals attending hospital for trivial surgery. Cases and controls were older than 30 and did not have a neoplasic history. We collected information on lifestyle with special emphases on tobacco and dietary habits. We included 371 cases and 496 controls. We found no protective effect for overall fruit consumption. For green leafy vegetables, the odds ratio (OR) was 0.92 [95% confidence interval (CI) = 0.32-2.69), and for other vegetables the OR was 0.77 (95% CI = 0.40-1.48) for the categories compared. We observed a reduced risk for broccoli and pumpkin intake. Although fruit consumption does not seem to be associated with a lower lung cancer risk, only the frequent consumption of specific green leafy vegetables and other vegetables might be associated with a reduced risk of lung cancer.

Autoimmune findings in patients with silicosis in Spain.

Background: Occupational exposure to silica is related to autoimmune diseases and features of autoimmunity, mainly autoantibodies. The study objectives were to estimate the prevalence of silicosis with associated autoimmune findings or diagnosed autoimmune diseases in Spain, and to assess the clinical and functional characteristics of affected patients. Methods: This is a multicentre prospective study in patients diagnosed with silicosis. Autoantibodies analysed were antinuclear antibodies, isotypes IgA, IgM and IgG, rheumatoid factor, anticyclic citrullinated peptide, anti-Scl70, anti-Ro, and anti-LA. Pulmonary function tests were performed. Results: Autoimmunity was assessed in 105 patients. Autoimmune findings were recorded in 29 (27%) patients, including antinuclear antibodies (n=21), anti-Ro (n=7), rheumatoid factor (n=5) and anti-Scl70 (n=3). Autoimmune disease was diagnosed in 16 (15%) patients, mainly rheumatoid arthritis (n=7) and systemic lupus erythematosus (n=4). Patients with silicosis and autoimmune findings had a lower mean time of exposure to silica and showed a trend toward lower values in pulmonary function tests. Conclusions: Autoimmune findings and diagnosis of autoimmune diseases were frequent in patients with silicosis in Spain.

Impact of a Home Telehealth Program After a Hospitalized COPD Exacerbation: A Propensity Score Analysis.

INTRODUCTION: Currently there is lack of data regarding the impact of a home telehealth program on readmissions and mortality rate after a COPD exacerbation-related hospitalization. OBJECTIVE: To demonstrate if a tele-monitoring system after a COPD exacerbation admission could have a favorable effect in 1-year readmissions and mortality in a real-world setting. METHODS: This is an observational study where we compared an intervention group of COPD patients treated after hospitalization that conveyed a telehealth program with a followance period of 1 year with a control group of patients evaluated during one year before the intervention began. A propensity-score analyses was developed to control for confounders. The main clinical outcome was 1-year all-cause mortality or COPD-related readmission. RESULTS: The analysis comprised 351 telemonitoring patients and 495 patients in the control group. The intervention resulted in less mortality or readmission after 12 months (35.2% vs. 45.2%; hazard ratio [HR] 0.71 [95% CI=0.56-0.91]; p=0.007). This benefit was maintained after the propensity score analysis (HR=0.66 [95% CI=0.51-0.84]). This benefit, which was seen from the first month of the study and during its whole duration, is maintained when mortality (HR=0.54; 95% CI=[0.36-0.82]) or readmission (subdistribution hazard ratio [SHR] 0.66; 95% CI=[0.50-0.86]) are analyzed separately. CONCLUSION: Telemonitoring after a severe COPD exacerbation is associated with less mortality or readmissions at 12 months in a real world clinical setting.

COVID-19 pneumonia in Galicia (Spain): Impact of prognostic factors and therapies on mortality and need for mechanical ventilation.

INTRODUCTION: This study was aimed to identify risk factors associated with unfavorable outcomes (composite outcome variable: mortality and need for mechanical ventilation) in patients hospitalized in Galicia with COVID-19 pneumonia. METHODS: Retrospective, multicenter, observational study carried out in the 8 Galician tertiary hospitals. All Patients admitted with confirmed COVID-19 pneumonia from 1st of March to April 24th, 2020 were included. A multivariable logistic regression analysis was performed in order to identify the relationship between risk factors, therapeutic interventions and the composite outcome variable. RESULTS: A total of 1292 patients (56.1% male) were included. Two hundred and twenty-five (17.4%) died and 327 (25.3%) reached the main outcome variable. Age [odds ratio (OR) = 1.03 (95% confidence interval (CI): 1.01-1.04)], CRP quartiles 3 and 4 [OR = 2.24 (95% CI: 1.39-3.63)] and [OR = 3.04 (95% CI: 1.88-4.92)], respectively, Charlson index [OR = 1.16 (95%CI: 1.06-1.26)], SaO2 upon admission [OR = 0.93 (95% CI: 0.91-0.95)], hydroxychloroquine prescription [OR = 0.22 (95%CI: 0.12-0.37)], systemic corticosteroids prescription [OR = 1.99 (95%CI: 1.45-2.75)], and tocilizumab prescription [OR = 3.39 (95%CI: 2.15-5.36)], significantly impacted the outcome. Sensitivity analysis using different alternative logistic regression models identified consistently the ratio admissions/hospital beds as a predictor of the outcome [OR = 1.06 (95% CI: 1.02-1.11)]. CONCLUSION: These findings may help to identify patients at hospital admission with a higher risk of death and may urge healthcare authorities to implement policies aimed at reducing deaths by increasing the availability of hospital beds.

Polymorphisms in the BER and NER pathways and their influence on survival and toxicity in never-smokers with lung cancer.

Polymorphisms in DNA repair pathways may play a relevant role in lung cancer survival in never-smokers. Furthermore, they could be implicated in the response to chemotherapy and toxicity of platinum agents. The aim of this study was to evaluate the influence of various genetic polymorphisms in the BER and NER DNA repair pathways on survival and toxicity in never-smoker LC patients. The study included never-smokers LC cases diagnosed from 2011 through 2019, belonging to the Lung Cancer Research In Never Smokers study. A total of 356 never-smokers cases participated (79% women; 83% adenocarcinoma and 65% stage IV). Survival at 3 and 5 years from diagnosis was not associated with genetic polymorphisms, except in the subgroup of patients who received radiotherapy or chemo-radiotherapy, and presented with ERCC1 rs3212986 polymorphism. There was greater toxicity in those presenting OGG1 rs1052133 (CG) and ERCC1 rs11615 polymorphisms among patients treated with radiotherapy or chemo-radiotherapy, respectively. In general, polymorphisms in the BER and NER pathways do not seem to play a relevant role in survival and response to treatment among never-smoker LC patients.

Validation of Calprotectin As a Novel Biomarker For The Diagnosis of Pleural Effusion: a Multicentre Trial.

Discriminating between malignant pleural effusion (MPE) and benign pleural effusion (BPE) remains difficult. Thus, novel and efficient biomarkers are required for the diagnosis of pleural effusion (PE). The aim of this study was to validate calprotectin as a diagnostic biomarker of PE in clinical settings. A total of 425 patients were recruited, and the pleural fluid samples collected had BPE in 223 cases (53.7%) or MPE in 137 patients (33%). The samples were all analysed following the same previously validated clinical laboratory protocols and methodology. Calprotectin levels ranged from 772.48 to 3,163.8 ng/mL (median: 1,939 ng/mL) in MPE, and 3,216-24,000 ng/mL in BPE (median: 9,209 ng/mL; p < 0.01), with an area under the curve of 0.848 [95% CI: 0.810-0.886]. For a cut-off value of ≤ 6,233.2 ng/mL, we found 96% sensitivity and 60% specificity, with a negative and positive predictive value, and negative and positive likelihood ratios of 96%, 57%, 0.06, and 2.4, respectively. Multivariate analysis showed that low calprotectin levels was a better discriminator of PE than any other variable [OR 28.76 (p < 0.0001)]. Our results confirm that calprotectin is a new and useful diagnostic biomarker in patients with PE of uncertain aetiology which has potential applications in clinical practice because it may be a good complement to cytological methods.

Lung cancer survival in never-smokers and exposure to residential radon: Results of the LCRINS study.

We aimed to evaluate lung cancer survival in never-smokers, both overall and specifically by sex, exposure to residential-radon, age, histological type, and diagnostic stage. We included lung cancer cases diagnosed in a multicentre, hospital-based, case-control-study of never-smoker patients, diagnosed from January-2011 to March-2015 (Lung Cancer Research In Never Smokers study). 369 never-smokers (79% women; median age 71 years; 80% adenocarcinoma; 66% stage IV) were included. Median overall survival, and at one, 3 and 5 years of diagnosis was 18.3 months, 61%, 32% and 22%, respectively. Higher median survival rates were obtained for: younger age, adenocarcinoma, actionable mutations, and earlier-stage at diagnosis. Higher indoor radon showed a higher risk of death in multivariate analysis. Median lung cancer survival in never-smokers seems higher than that in ever-smokers. Patients with actionable mutations have a significantly higher survival. Higher indoor-radon exposure has a negative effect on survival.

Residential radon, genetic polymorphisms in DNA damage and repair-related.

OBJECTIVES: To analyze the relationship of GSTT1, GSTM1, XRCC1 (rs25487), ERCC1 (rs11615, rs3212986), ERCC2 (rs13181), XRCC3 (rs861539), OGG1 (rs1052133), and Alpha-1-Antitrypsin mutations (AAT) with the risk of lung cancer in never-smokers, and ascertain if there is an effect modification between these polymorphisms and residential radon exposure. MATERIAL AND METHODS: We designed a multicenter hospital-based case-control study in a radon-prone area. 322 cases and 338 controls, all never-smokers, were included. They were selected using a frequency sampling based on sex and age distribution of the cases. Participants donated 3 ml. of whole blood used to determine genotype for polymorphisms. They placed a radon detector to measure residential radon exposure in their dwelling. RESULTS: The OR for deleted GSTM1 patients was 3.46 (95% CI = 1.52-7.89) at residential radon exposures above 200 Bq/m3. The ERCC1 rs3212986 polymorphism was the most associated with the risk of developing lung cancer, both for low and high radon exposures. The ERCC1 rs321986 GT and TT genotypes (at radon concentrations >200 Bq/m3) were more significantly associated with higher lung cancer risk (OR = 2.40, 95% CI = 1.29-4.45; OR = 4.45, 95% CI = 1.26-15.7, respectively). CONCLUSIONS: These findings support the hypothesis that certain polymorphisms in genes involved in DNA-repair and carriers of GSTM1 deletion have an increased risk of lung cancer in never-smokers exposed to residential radon.

Small Cell Lung Cancer. Methodology and Preliminary Results of the SMALL CELL Study. / Cáncer de pulmón microcítico. Metodología y resultados preliminares del estudio SMALL CELL.

INTRODUCTION: Small cell lung cancer (SCLC) is the most aggressive histologic type of lung cancer, and accounts for approximately 10%-15% of all cases. Few studies have analyzed the effect of residential radon. Our aim is to determine the risk factors of SCLC. METHODS: We designed a multicenter, hospital-based case-control study with the participation of 11 hospitals in 4 autonomous communities. RESULTS: Results of the first 113 cases have been analyzed, 63 of which included residential radon measurements. Median age at diagnosis was 63 years; 11% of cases were younger than 50 years of age; 22% were women; 57% had extended disease; and 95% were smokers or former smokers. Median residential radon concentration was 128Bq/m3. Concentrations higher than 400Bq/m3 were found in 8% of cases. The only remarkable difference by gender was the percentage of never smokers, which was higher in women compared to men (P<.001). Radon concentration was higher in patients with stageIV disease (non-significant difference) and in individuals diagnosed at 63 years of age or older (P=.032). CONCLUSIONS: A high percentage of SCLC cases are diagnosed early and there is a predominance of disseminated disease at diagnosis. Residential radon seems to play an important role on the onset of this disease, with some cases having very high indoor radon concentrations.

Environmental tobacco smoke exposure and EGFR and ALK alterations in never smokers' lung cancer. Results from the LCRINS study.

Environmental tobacco smoke (ETS) exposure is a main risk factor of lung cancer in never smokers. Epidermal Growth Factor Receptor (EGFR) mutations and ALK translocations are more frequent in never smokers' lung cancer than in ever-smokers. We performed a multicenter case-control study to assess if ETS exposure is associated with the presence of EGFR mutations and its types and if ALK translocations were related with ETS exposure. All patients were never smokers and had confirmed lung cancer diagnosis. ETS exposure during childhood showed a negative association on the probability of EGRF mutation though not significant. Exposure during adulthood, at home or at workplace, did not show any association with EGFR mutation. The mutation type L858R seemed the most associated with a lower probability of EGFR alterations for ETS exposure at home in adult life. There is no apparent association between ETS exposure and ALK translocation. These results might suggest that ETS exposure during childhood or at home in adult life could influence the EGFR mutations profile in lung cancer in never smokers, reducing the probability of presenting EFGR mutation.

[The EpicliCP-2003 study: A multicenter epidemiological and clinical study of lung cancer in Spain]. / Estudio multicéntrico epidemiológico-clínico de cáncer de pulmón en España (estudio EpicliCP-2003).

OBJECTIVE: Mortality due to lung cancer in Spain is increasing continuously. The aim of the present study was to collect information on the hospital incidence of lung cancer, as well as information on clinical management, in different regions of Spain. MATERIAL AND METHODS: A prospective observational study of patients diagnosed with lung cancer in 2003 was carried out in 13 centers in 9 autonomous communities. Epidemiological, clinical, diagnostic, and therapeutic variables were assessed. RESULTS: Of a total population of 2,726,601 inhabitants (1 346 483 men and 1 380 118 women), 1064 male and 125 female lung cancer patients were included. The incidence standardized to the world population varied between 42.4/100,000 and 61.8/100,000 in men and between 1.5/100,000 and 8.6/100,000 in women. Overall, 51% were aged over 70 years, and 97.5% of the men and 32% of the women were smokers or ex-smokers. Cytologic or histologic confirmation was obtained for 93.1% of the cases (20.8% of which were small cell lung cancers and 79.2% were non-small cell lung cancers). The main initial symptoms were cough, chest pain, and weight loss. In 13.7%, lung cancer was suspected because of abnormal chest x-ray. The percentage with clinical TNM stages I and II ranged from 6.3% to 26.9%. The most common stage was stage IV in all centers. The percentage of patients undergoing surgery ranged from 2.5% to 20.6%, with a mean of 14.8% (19.9% of whom were patients with non-small cell lung cancer); 27% received palliative treatment only. CONCLUSIONS: The proportion of women suffering from lung cancer increased with respect to previous studies, with notable differences among regions. Despite diagnostic improvements, the percentage of patients undergoing surgery is low, though interregional variation is considerable.

Residential radon and lung cancer characteristics in never smokers.

PURPOSE: The aim of this study is to assess if there is a relationship between residential radon and lung cancer histological types and patients' age at diagnosis. MATERIALS AND METHODS: We conducted a multicenter hospital-based case-control study with eight participating hospitals. We included 216 never-smoking cases with primary lung cancer and 329 never-smoking controls. Controls were frequency matched with cases on age and sex distribution. Of them, 198 cases (91.7%) and 275 controls (83.5%) had residential radon measurements. RESULTS: Lung cancer risk reached statistical significance only for adenocarcinoma (Odds ratio [OR] 2.19; 95% Confidence interval [CI] 1.44-3.33), for other histologies the results were marginally significant. Residential radon level was higher for patients diagnosed before 50 and 60 years old than for older lung cancer cases. CONCLUSIONS: Residential radon in never smokers seems to be a risk factor for all lung cancer histologies. Individuals diagnosed at a younger age have a higher residential radon concentration, suggesting an accumulative effect on lung cancer appearance.