Occupation and smoking as risk factors for lung cancer: a population-based case-control study

Lung cancer risk associated with occupations in women: a pooling study

BACKGROUND

Occupation is an important risk factor for lung cancer. This knowledge is mainly based on studies conducted on men, with the results being generalized to women.

AIMS

We aimed to identify the relationship between different occupations and lung cancer in women.

METHODS

Pooling study in which data were pooled from six case-control studies conducted at 13 Spanish hospitals and 1 hospital in Portugal. Each woman's longest held job was coded as per the ISCO-08. Results were adjusted for age, smoking, and exposure to residential radon.

RESULTS

The study population comprised 1262 women: 618 cases and 644 controls. The reference group were white-collar workers. The adjusted multivariate analysis showed a higher risk of developing lung cancer among teaching professionals (odds ratio [OR]: 4.36; 95% confidence interval [CI] 1.73-11.02), cooks (OR: 3.59; 95% CI 1.52-8.48), domestic cleaners and helpers (OR: 2.98; 95% CI 1.54-5.78), homemakers (OR: 2.30; 95% CI 1.26-4.21) and crop farmers, livestock farmers and gardeners (OR: 2.06, 95% CI: 1.11-3.81). For adenocarcinoma, the highest risk was observed in teaching professionals, and for small-cell carcinoma, the highest risk was observed in cooks. Higher risks were observed for small-cell carcinoma compared to other histological types.

CONCLUSIONS

Some occupations may be associated with an increased risk of lung cancer in women and this risk could vary by histologic subtype; however, further research is needed to confirm these associations. In any case, protection measures must be implemented in the workplace aimed at reducing the risk of lung cancer among women workers, and more studies exclusively focused on women are warranted.

Wood dust exposure and small cell lung cancer: a systematic review and meta-analysis

INTRODUCTION

Occupational exposure role on small cell lung cancer (SCLC) onset has been little studied. Wood dust has been recognized as a human carcinogen, and many occupations have high wood-dust exposure. The aim of this study was therefore to perform a systematic review and meta-analysis of the scientific literature to summarize and analyse the risks of wood dust-related occupations on development of SCLC, taking tobacco use into account.

METHODS

We conducted a literature search of PubMed, EMBASE, Web of Science and Cochrane using a predefined strategy and including case-control and cohort studies assessing occupational exposure to wood dust or wood dust-related occupations. To perform the meta-analysis, the odds ratio (OR) and 95% confidence interval (CI) of each of the studies were extracted. A random-effects model was fitted using the DerSimonian Laird method. Sensitivity and subgroup analyses were performed. Quality was assessed using the Office and Health Assessment and Translation (OHAT) for human and animal studies instrument.

RESULTS

Eleven studies with a total of 2,368 SCLC cases and 357,179 controls were included. Overall, exposure to wood dust significantly increases risk of SCLC (RR = 1.41, 95% CI 1.11-1.80), with low heterogeneity between studies (I2 = 40%). The association was maintained in studies conducted on males (RR = 1.41, 95% CI 1.12-1.78) but not in those conducted on females/both sexes (RR = 1.37, 95% CI 0.35-3.44). Sensitivity analysis showed that none of the studies significantly modified the results.

CONCLUSIONS

Our results support that exposure to wood-dust can increase the risk of SCLC. Although the level of evidence is low, there are strong arguments to recommend the implementation of effective control measures to reduce exposure in occupational settings, as a means of preventing SCLC.

IMPACT STATEMENT

The results of this study support that exposure to wood-dust can increase the risk of developing small cell lung cancer. Determining the impact of occupational exposure on workers is essential to improve their individual protection and prevention. There is a strong case for recommending the implementation of control measures to reduce occupational exposure to wood dust, specifically for highly exposed occupations such as carpenters and sawmills, in order to prevent small cell lung cancer.

Occupational exposure to endotoxins and small cell lung cancer: a systematic review with meta-analysis

The relationship of occupational exposure to endotoxins with different histologic subtypes of lung cancer has not been established. Our objective was to conduct a systematic review with meta-analysis to assess the effect of exposure to endotoxins on the development of small cell lung cancer (SCLC). A bibliographic search was conducted using MEDLINE, Embase, CENTRAL, and Web of Science databases until December 2022, including all cohort and/or case-control studies that examined occupational exposure to endotoxins and SCLC. Risk of bias was assessed using the U.S. Office of Health Assessment and Translation tool. A random effects model was applied, publication bias were assessed, and a sensitivity analysis was conducted. Four papers were selected for meta-analysis purposes. A total of 144 incident cases of SCLC and 897 population or hospital controls were included. Occupational exposure to endotoxins was considered for textile/leather industry and agricultural sector workers exposed to endotoxins originating from wool, cotton, or leather dust. Except for one study, all investigations were classified as having a low probability of risk of biases. The results of the meta-analysis were not statistically significant (pooled OR: 0.86; 95% CI:0.69-1.08). In addition, neither between-study heterogeneity (I2=0%;p=0.92) nor publication bias was observed (p=0.49). The results of the sensitivity analysis, after including five studies that assessed the risk of SCLC among textile industry and crop/livestock farm workers (not specifically exposed to endotoxins), showed a negative statistically non-significant association and low between-study heterogeneity (pooled OR: 0.90; 95% CI:0.79-1.02; I2=22%;p=0.23). Subjects exposed to occupational exposure to endotoxins seem to exhibit a negative association with the development of SCLC, although the results are not conclusive.

Occupation as a risk factor of small cell lung cancer

Small cell lung cancer (SCLC) comprises approximately 10% of all lung cancer cases. Tobacco is its main risk factor; however, occupation might play a role in this specific lung cancer subtype. The effect of occupation on SCLC risk has been hardly studied and therefore we aim to assess the role of occupation on the risk of SCLC. To do this, we designed a multicentric, hospital-based, case-control study. Cases consisted exclusively in SCLC patients and controls were recruited from patients having minor surgery at the participating hospitals. Face to face interviews emphasizing occupation and tobacco consumption were held and residential radon was also measured. Logistic regression models were adjusted with odds ratios with 95%CI as estimations of the effect. 423 cases and 905 controls were included. Smoking prevalence was higher in cases compared to controls. Those who worked in known-risk occupations for lung cancer showed an OR of 2.17 (95%CI 1.33; 3.52), with a similar risk when men were analysed separately. The results were adjusted by age, sex, smoking and indoor radon exposure. Those who worked in known-risk occupations and were moderate or heavy smokers had a SCLC risk of 12.19 (95%CI 5.68-26.38) compared with never or moderate smokers who had not worked in such occupations. Occupation is a relevant risk factor of SCLC, and it seems that its effect is boosted when tobacco smoking is present.

An Innovative Tool to Control Occupational Radon Exposure

After smoking, indoor radon is the main contributor to lung cancer in many countries. The European Union (EU) Directive 2013/59/Euratom establishes a maximum reference level of 300 Bq/m³ of radon concentration in the workplace, and an effective dose limit of 20 mSv per year for workers. If the radon concentration in a workplace exceeds the reference level, constructive mitigation applies. When constructive mitigation is not feasible, we propose to keep workers' effective dose below 6 mSv per year (category B of exposed workers) by controlling occupancy time. Setting the maximum annual dose at 6 mSv protects workers' health and eases the regulatory requirements for employers. If multisite workers are present, each worker has to be monitored individually by tracking the time spent and the radon concentration at each worksite. This paper shows a software tool for employers to perform this complex tracking in an accurate, conservative, and transparent manner, and in compliance with the EU by-laws.

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.

[Occupational lung cancer in Sør-Trøndelag county]

BACKGROUND

Lung cancer can be caused by occupational exposure. This is not always recognised or reported, and not all patients receive the benefits to which they are entitled.

MATERIAL AND METHOD

We collected occupational case histories for patients from Sør-Trøndelag county with a first-time diagnosis of lung cancer. The number of reported cases of occupationally related lung cancer was collected from the Norwegian Labour Inspection Authority, and information on approval of occupational illness was collected from the Norwegian Labour and Welfare Authority (NAV).

RESULTS

105 patients with lung cancer took part in the study, 73 men and 32 women. Among the men, altogether 12 cases (16%) were assessed as likely and 16 (22%) as possibly occupationally related. Among the women, none of the cases were assessed as occupationally related. The reporting frequency from the health regions to the Norwegian Labour Inspection Authority varied from 1.7% to 5.1%. Altogether 9 out of 11 likely cases and 5 out of 12 possible cases of occupationally related lung cancer were granted injury compensation by the Norwegian Labour and Welfare Authority.

INTERPRETATION

In this study, we found that approximately 20% of the cases of lung cancer in men are occupationally related, and that the underreporting of occupationally related lung cancer appears to be considerable. The obligation of doctors to report to the Norwegian Labour Inspection Authority should be made better known. Most likely, more patients would have had their lung cancer verified as an occupational illness and could have received injury compensation if they had been aware of the opportunity to apply for this.

Metformin decreases lung cancer risk in diabetic patients in a dose-dependent manner

OBJECTIVES

Higher risk of lung cancer has been noted in patients with type 2 diabetes mellitus (DM). Some observational studies have shown a reduced risk of lung cancer in DM patients taking metformin, but a dose-response relationship has never been reported. The aim of this study is to exam the association between the dose of metformin and the incidence of lung cancer in a Chinese population.

MATERIALS AND METHODS

The dataset used for this nationwide population-based study is a cohort of 1 million subjects randomly sampled from individuals enrolled in the Taiwan National Health Insurance system. We enrolled all subjects with newly diagnosed type 2 DM between 1997 and 2007. Subjects with a diagnosis of neoplasm before DM diagnosis, those using metformin before DM diagnosis, those with polycystic ovary syndrome, and those with a DM diagnosis before their 15 years of age were excluded. The demographic data and duration, cumulative dose and intensity of metformin use were compared between patients developing lung cancer and those without lung cancer.

RESULTS

Totally, 47,356 subjects were identified. After adjusting for age, gender, and modified Charlson Comorbidity Index score, the utilization of metformin was an independent protecting factor, and the risk of developing lung cancer decreased progressively with either the higher cumulative dose or the higher intensity of metformin use.

CONCLUSIONS

This study revealed that the use of metformin decreased the risk of lung cancer in a dose-dependent manner in patients with type 2 DM. The chemo-preventive effect of metformin deserves further study.

Consumption of fruit and vegetables and risk of lung cancer: a case-control study in Galicia, Spain

OBJECTIVE

We analyzed the effect of fruit and vegetable intake on lung cancer risk in a population in northwest Spain.

METHODS

We analyzed data from a hospital-based case-control study including 295 histologically confirmed cases and 322 controls. Controls were patients attending the hospital for minor surgery. There was a minimum age limit of 35 y and sampling was carried out on a sex-frequency basis.

RESULTS

After adjustment for sex, age, tobacco use, and occupation, no protective effect of overall consumption of fruit was present (odds ratio 1.49, 95% confidence interval 0.81-2.73). Green leafy vegetables conferred a protective effect (odds ratio 0.50, 95% confidence interval 0.30-0.83).

CONCLUSION

These findings indicate that green leafy vegetables, rather than fruit, might have a genuine protective effect against lung cancer.

Meat and fish consumption and risk of lung cancer: A case-control study in Galicia, Spain

Diet is one of the elements that may influence the development of lung cancer. To ascertain the relationship between meat and fish consumption and the appearance of this disease, a case-control study was conducted on a population in Galicia (NW Spain), with a sample of 295 cases and 322 controls. All cases had histologic confirmation, and controls were individuals who were attending the hospital to undergo trivial surgery. All subjects were over 35, and sampling was based on sex frequency. Frequent consumption of meat seemed to have a protective effect, with an OR of 0.24 (95% CI 0.11-0.50), an effect that was maintained for pork consumption (OR 0.35; 95% CI 0.18-0.67). In contrast, consumption of fish showed an association with lung cancer, with an OR of 1.67 (95% CI 0.99-2.81), an association that extended to both white (OR 1.61 95% CI 0.93-2.79) and blue fish (OR 2.03 95% CI 1.23-3.34). Consumption of meat seems to reduce the risk of lung cancer, whereas consumption of fish could exert an influence by increasing the risk of this disease.

Occupation and lung cancer mortality in a nationally representative U.S. Cohort: The National Health Interview Survey (NHIS)

OBJECTIVE

The objective of this study was to assess the risk of lung cancer mortality in a nationally representative sample of U.S. workers by occupation.

METHODS

National Death Index linkage identified 1812 lung cancer deaths among 143,863 workers who participated in the 1987, 1988, and 1990-1994 National Health Interview Surveys.

RESULTS

Current and former smoking status was predictive of lung cancer mortality (hazard ratio [HR] = 15.1 and 3.8, respectively). Occupations with significantly higher risk for age- and smoking-adjusted lung cancer mortality included heating/air/refrigeration mechanics (HR = 3.0); not specified mechanics and repairers (HR = 2.8); financial records processing occupations (HR = 1.8); freight, stock, and materials handlers (HR = 1.5); and precision production occupations (HR = 1.4).

CONCLUSION

Although tobacco use continues to be the single most important risk factor for lung cancer mortality, occupational exposure to lung carcinogens should be targeted as well to further reduce the burden of lung cancer.

Type of wine and risk of lung cancer: a case-control study in Spain

BACKGROUND

Few epidemiological studies have examined the effect of wine on the risk of lung cancer. A study was therefore undertaken to estimate the effect of wine consumption, both overall and by type of wine, on the risk of developing lung cancer.

METHODS

A hospital based case-control study was conducted on 319 subjects (132 cases, 187 controls) in 1999-2000. All subjects were interviewed about their lifestyles with particular reference to alcohol consumption and tobacco use. The results were analysed using non-parametric logistic regression. The main outcome measure was the risk of lung cancer associated with consumption of wine and its individual types.

RESULTS

A very slight but significant association was observed between the risk of lung cancer and white wine consumption (odds ratio (OR) 1.20 for each daily glass). Red wine consumption, on the other hand, had an OR of 0.43 (95% CI 0.19 to 0.96), with each daily glass of red wine having an inverse association with the development of lung cancer (OR 0.87 (95% CI 0.77 to 0.99)). There was no apparent association between lung cancer and consumption of beer or spirits.

CONCLUSIONS

These results suggest that the consumption of red wine is negatively associated with the development of lung cancer. Further studies are needed to test this finding in cancer induced laboratory animals.

Dose-response relationship between tobacco and lung cancer: new findings

The purpose of this work is to model the relationship between smoking-related variables and the risk of lung cancer by using parametric and non-parametric models. A hospital-based case-control study was conducted to ascertain the influence of smoking on risk of lung cancer. We used parametric logistic regression with a series of categorized independent variables and non-parametric logistic regression models. Such models allow for variables to be treated as continuous, since they avoid arbitrariness in the selection of cut-offs and furnish information on the dose-risk relationship. The results point to the possible existence of a saturation effect for a lifetime tobacco consumption of around 25 000-30 000 packets. Duration of habit and years of abstinence show a linear relationship marked by opposite, though similar, slopes, which would seem to indicate that for every year of smoking, risk rises by an amount (8.00%, 95% confidence interval (CI) 5.94-10.06) equal to the decline in risk for every year of abstinence (6.98%, 95% CI 2.53-11.84). Lastly, a lower age of smoking initiation appears to have an influence, although non-significant, on the appearance of the disease. The risk of lung cancer due to duration of the habit would seem to be proportional to years of abstinence, and there could be a saturation effect with respect to lifetime tobacco consumption.