Lung cancer risk in painters: results from the SYNERGY pooled case-control study consortium

Lung Cancer Risks Associated with Occupational Exposure to Pairs of Five Lung Carcinogens: Results from a Pooled Analysis of Case-Control Studies (SYNERGY)

BACKGROUND

While much research has been done to identify individual workplace lung carcinogens, little is known about joint effects on risk when workers are exposed to multiple agents.

OBJECTIVES

We investigated the pairwise joint effects of occupational exposures to asbestos, respirable crystalline silica, metals (i.e., nickel, chromium-VI), and polycyclic aromatic hydrocarbons (PAH) on lung cancer risk, overall and by major histologic subtype, while accounting for cigarette smoking.

METHODS

In the international 14-center SYNERGY project, occupational exposures were assigned to 16,901 lung cancer cases and 20,965 control subjects using a quantitative job-exposure matrix (SYN-JEM). Odds ratios (ORs) and 95% confidence intervals (CIs) were computed for ever vs. never exposure using logistic regression models stratified by sex and adjusted for study center, age, and smoking habits. Joint effects among pairs of agents were assessed on multiplicative and additive scales, the latter by calculating the relative excess risk due to interaction (RERI).

RESULTS

All pairwise joint effects of lung carcinogens in men were associated with an increased risk of lung cancer. However, asbestos/metals and metals/PAH resulted in less than additive effects; while the chromium-VI/silica pair showed marginally synergistic effect in relation to adenocarcinoma (RERI: 0.24; CI: 0.02, 0.46; p = 0.05). In women, several pairwise joint effects were observed for small cell lung cancer including exposure to PAH/silica (OR = 5.12; CI: 1.77, 8.48), and to asbestos/silica (OR = 4.32; CI: 1.35, 7.29), where exposure to PAH/silica resulted in a synergistic effect (RERI: 3.45; CI: 0.10, 6.8).

DISCUSSION

Small or no deviation from additive or multiplicative effects was observed, but co-exposure to the selected lung carcinogens resulted generally in higher risk than exposure to individual agents, highlighting the importance to reduce and control exposure to carcinogens in workplaces and the general environment. https://doi.org/10.1289/EHP13380.

Etiology of lung cancer: Evidence from epidemiologic studies

Lung cancer is one of the leading causes of cancer incidence and mortality worldwide. While smoking, radon, air pollution, as well as occupational exposure to asbestos, diesel fumes, arsenic, beryllium, cadmium, chromium, nickel, and silica are well-established risk factors, many lung cancer cases cannot be explained by these known risk factors. Over the last two decades the incidence of adenocarcinoma has risen, and it now surpasses squamous cell carcinoma as the most common histologic subtype. This increase warrants new efforts to identify additional risk factors for specific lung cancer subtypes as well as a comprehensive review of current evidence from epidemiologic studies to inform future studies. Given the myriad exposures individuals experience in real-world settings, it is essential to investigate mixture effects from complex exposures and gene-environment interactions in relation to lung cancer and its subtypes.

Lung cancer risk in relation to jobs held in a nationwide case-control study in Iran

BACKGROUND

Globally, lung cancer is the most frequent occupational cancer, but the risk associated with the occupations or occupational environment in Iran is not clear. We aimed to assess occupations with the risk of lung cancer.

METHODS

We used the IROPICAN nationwide case-control study data including 658 incident lung cancer cases and 3477 controls. We assessed the risk of lung cancer in relation to ever working in major groups of International Standard Classification of Occupations, high-risk occupations for lung cancer and duration of employment and lung cancer subtype among construction workers and farmers while controlling for cigarette smoking and opium consumption. We used unconditional regression logistic models to estimate ORs for the association between increased lung cancer risk and occupations.

RESULTS

We observed elevated ORs for lung cancer in male construction workers (OR=1.4; 95% CI: 1.0 to 1.8), petroleum industry workers (OR=3.2; 95% CI: 1.1 to 9.8), female farmers (OR=2.6; 95% CI: 1.3 to 5.3) and female bakers (OR=5.5; 95% CI: 1.0 to 29.8). A positive trend by the duration of employment was observed for male construction workers (p< 0.001). Increased risk of squamous cell carcinoma was observed in male construction workers (OR=1.9; 95% CI: 1.2 to 3.0) and female farmers (OR=4.3; 95% CI: 1.1 to 17.2), who also experienced an increased risk of adenocarcinoma (OR=3.8; 95% CI: 1.4 to 9.9).

DISCUSSION

Although we observed associations between some occupations and lung cancer consistent with the literature, further studies with larger samples focusing on exposures are needed to better understand the occupational lung cancer burden in Iran.

Lung Cancer in the French West Indies: Role of Sugarcane Work and Other Occupational Exposures

OBJECTIVE

Our aim was to study the role of occupational exposures in lung cancer risk in the French West Indies, with special attention to some specific activities, such as sugarcane work, that can only be studied in a limited number of populations.

METHODS

We used data from a population-based case-control study that included 147 incident lung cancer cases and 405 controls. Smoking histories and detailed occupational histories with descriptions of tasks and substances were collected by questionnaire during face-to-face interviews. Odds ratios (OR) adjusted for sex, age, region, smoking status, and cigarette pack-years and 95% confidence intervals (95% CI) were estimated by unconditional logistic regression.

RESULTS

Significantly increased risks of lung cancer were found in sugarcane farm workers (OR = 2.7; 95% CI 1.1-6.6) and more generally in the sugarcane-growing sector (OR = 2.5; 95% CI 1.0-6.3) and to a lesser extent in rum production. Elevated risks of lung cancer were also observed among other agricultural workers, painters, warehouse porters, labourers, and maintenance and motor vehicle repair workers. Exposure to herbicides in sugarcane cultivation was associated with an increased risk of lung cancer (OR = 2.6; 95% CI 0.9-7.6).

CONCLUSION

These results show that occupational exposures contributed to lung cancer risk in the French West Indies, and highlighted the role of exposures related to sugarcane work.

Lung cancer and occupational exposure: hospital-based case-control study

OBJECTIVE

To analyze the relationship between occupation and lung cancer in patients at a national referral hospital for cancer care in southern Brazil.

METHOD

Hospital-based case-control study conducted between February and October 2019. Occupational histories were coded according to international classifications and translated into occupations associated with lung cancer (List A and B). The odds ratios were adjusted for smoking, with a 95% confidence interval, calculated by conditional logistic regression.

RESULTS

99 cases and 227 controls were included. Among men, the occupation of painters (list A) was associated with lung cancer (OR = 14.3; 95% CI: 1.8-116.5), there were no occupations in list B associated with lung cancer. In women, no increased risks were found.

CONCLUSIONS

It has been shown that exposure to occupational carcinogens among repair and construction painters increases the risk of lung cancer.

Câncer de pulmão e exposição ocupacional: estudo caso-controle de base hospitalar

RESUMO Objetivo Analisar a relação entre ocupação e câncer de pulmão em pacientes de um hospital de referência nacional para atendimento oncológico no Sul do Brasil. Método Estudo caso-controle de base hospitalar realizado entre fevereiro e outubro de 2019. Os históricos ocupacionais foram codificados de acordo com classificações internacionais e traduzidos em ocupações associadas ao câncer de pulmão (Lista A e B). As odds ratios foram ajustadas para tabagismo, com intervalo de confiança de 95%, calculadas por regressão logística condicional. Resultados Foram incluídos 99 casos e 227 controles. Entre os homens a ocupação de pintores (lista A) estava associada ao câncer de pulmão (OR= 14,3; IC 95%: 1,8-116,5), não houve ocupações da lista B associadas ao câncer de pulmão. Nas mulheres não foram encontrados riscos aumentados. Conclusões Evidenciou-se que a exposição aos carcinógenos ocupacionais entre pintores de reparo e da construção civil aumentam o risco de câncer de pulmão.

Occupational cancer burden: the contribution of exposure to process-generated substances at the workplace

Respirable crystalline silica in mineral dust, wood dust, diesel engine exhaust emissions and welding fumes are among the most common process-generated substances to which millions of workers are exposed daily. The composition of process-generated substances can vary substantially, depending on the parameters of the underlying processes; for example, the composition and intensity of diesel motor emissions differs among the various generations of diesel engines and working environments (e.g. surface or underground mining). We illustrate how common these occupational exposures are and discuss challenges in estimating their global prevalence and their contribution to the burden of occupational cancer. Estimates of the number and proportion of workers exposed in most countries and on a global scale are generally scarce. A remarkable exception is based on the proactive bottom-up estimates generated within the European Network for Silica. Actions to reduce exposures and research to fill gaps in knowledge adapted to local settings are warranted to mitigate the occupational cancer burden, especially in under-researched settings including low- and middle-income countries.