Effects of occupation on risks of avoidable cancers in the Nordic countries

Differences in mortality between temporary and permanent workers: results from the Rome Longitudinal Study

OBJECTIVE

Precarious employment is characterised by instability, lack of protection and economic vulnerability. The objective of this study was to assess the association between temporary contracts and mortality.

DESIGN

Cohort study.

SETTING

Rome, Italy.

PARTICIPANTS

All employees, aged 25-65 years, from the Rome Longitudinal Study, followed from 21 October 2001 to the first date among death, migration from Rome, or 31 December 2015.

PRIMARY AND SECONDARY OUTCOME MEASURES

We investigated all-cause, cardiovascular and accidental mortality. We considered gender, age, place of birth, education, temporary versus permanent contract and sector of employment. We used Cox models to investigate the association between type of contract and total, cardiovascular and accidental mortality in men and women, overall and by employment sector.

RESULTS

We analysed 597 834 subjects. The proportion of temporary contracts varied by gender (9.6% in men and 13.3% in women) and by employment sector, ranging from 4.5% (public administration) to 27% (recreational, cultural, sports activities) in men. During the study period, 21 136 subjects died. Men with temporary contracts, compared with those with permanent positions, had greater overall mortality risk (HR=1.16, 95% CI 1.09 to 1.24), cardiovascular mortality (HR=1.29, 95% CI 1.14 to 1.45) and accidental mortality (HR=1.27, 95% CI 1.04 to 1.57). In men, the association varied widely among different economic sectors, with greater risks in the industry, building constructions and social services sectors. In women, there was no evidence of association between temporary contracts and mortality. A statistically significant association between temporary contracts and mortality in women was found in the sector of sales and transports only.

CONCLUSIONS

Temporary work should be considered a determinant of health, particularly for specific economic sectors.

Smoking-adjusted risk of kidney cancer by occupation: a population-based cohort study of Nordic men

Background: Evidence suggests that among some occupational groups, there is an elevated risk of kidney cancer. This might, however, derive from a difference in smoking habits across occupational groups. The objective of this study was to determine smoking-adjusted occupational variation in the incidence of kidney cancer in Nordic males.Material and Methods: The source population for this study consisted of 7.4 million men from Denmark, Iceland, Finland, Norway, and Sweden. Data on occupation were obtained from national censuses conducted in the years 1960-1990. Data on cancer cases came from national cancer registries. A proxy for the occupation-specific smoking prevalence among all Nordic men was calculated based on the occupation-specific smoking prevalence and lung cancer incidence data for Finnish men. Smoking-adjusted standardized incidence ratio (SIRadj) with 95% confidence intervals (95%CI) were calculated for each occupational group.Results: The highest SIRadj estimates were observed in dentists (1.32, 95%CI 1.06-1.62), journalists (1.20, 95%CI 1.00-1.42), physicians (1.19, 95%CI 1.03-1.36), public safety workers (1.18, 95%CI 1.10-1.26), administrators (1.17, 95%CI 1.13-1.22), military personnel (1.16, 95%CI 1.05-1.28), and religious workers (1.17, 95%CI 1.09-1.26). The lowest SIRadj was observed among forestry workers (0.82, 95%CI 0.76-0.88).Conclusions: Tobacco smoking plays an important role in the occupational variation in the risk of kidney cancer. The smoking-adjusted incidence of kidney cancer was increased in dentists, physicians, journalists, administrators, and public safety workers.

Impact of Heavy Metals on Host Cells: Special Focus on Nickel-Mediated Pathologies and Novel Interventional Approaches

BACKGROUND

Heavy metals [arsenic, aluminium, cadmium, chromium, cobalt, lead, nickel (Ni), palladium and titanium] are environmental contaminants able to impact with host human cells, thus, leading to severe damage.

OBJECTIVE

In this review, the detrimental effects of several heavy metals on human organs will be discussed and special emphasis will be placed on Ni. In particular, Ni is able to interact with Toll-like receptor-4 on immune and non-immune cells, thus, triggering the cascade of pro-inflammatory cytokines. Then, inflammatory and allergic reactions mediated by Ni will be illustrated within different organs, even including the central nervous system, airways and the gastrointestinal system.

DISCUSSION

Different therapeutic strategies have been adopted to mitigate Ni-induced inflammatoryallergic reactions. In this context, the ability of polyphenols to counteract the inflammatory pathway induced by Ni on peripheral blood leukocytes from Ni-sensitized patients will be outlined. In particular, polyphenols are able to decrease serum levels of interleukin (IL)-17, while increasing levels of IL- 10. These data suggest that the equilibrium between T regulatory cells and T helper 17 cells is recovered with IL-10 acting as an anti-inflammatory cytokine. In the same context, polyphenols reduced elevated serum levels of nitric oxide, thus, expressing their anti-oxidant potential. Finally, the carcinogenic potential of heavy metals, even including Ni, will be highlighted.

CONCLUSION

Heavy metals, particularly Ni, are spread in the environment. Nutritional approaches seem to represent a novel option in the treatment of Ni-induced damage and, among them, polyphenols should be taken into consideration for their anti-oxidant and anti-inflammatory activities.

Work environment factors and respiratory complaints in Norwegian cooks

PURPOSE

Norwegian cooks exhibit relatively high mortality, particularly from respiratory diseases. Both occupational hazards and lifestyle factors have been suggested as possible explanations. Negative health effects from exposure to cooking fumes are well documented in non-Western populations, and it has been claimed that cooking fumes in Western style cooking might be substantially different. We hypothesise that exposure to cooking fumes contributes to respiratory diseases also in professional cooks in Western countries. The aim of this study was to elucidate if specific work environment factors related to cooking fume exposure are determinants for respiratory morbidity in Norwegian cooks.

METHODS

We surveyed specific work environment factors and respiratory complaints in 553 subjects that were currently working as skilled cooks. Inclusion was based on the register of people that had graduated as skilled cooks in central Norway between 1988 and 2008. Determinants for the occurrence of respiratory complaints were explored by logistic regression.

RESULTS

Overall, 17.2% of subjects reported respiratory complaints at work, while 8.1% had chronic bronchitis. Those who performed frying for over half of their workday exhibited an increased odds ratio for having chronic bronchitis of 2.5 (95% CI 1.2-5.3). Using gas for frying and using a fryer in the kitchen were also related to the occurrence of respiratory complaints.

CONCLUSIONS

This study in Norwegian cooks demonstrates a relationship between the extent of frying and the occurrence of work-related respiratory complaints. Therefore, reducing exposure to cooking fumes could reduce respiratory complaints in cooks, and potentially help alleviate excess morbidity and mortality in this occupation.

Variation in Nordic Work-Related Cancer Risks after Adjustment for Alcohol and Tobacco

Background: Alcohol and tobacco strongly increases the risk of cancers of the tongue, mouth, pharynx, larynx, and oesophagus, and are also established risk factors for cancer of the liver, colon, and rectum. It is well documented that these habits are unequally distributed among occupational groups. Most occupational cohort studies lack information on these potentially important confounders, and may therefore be prone to bias. Aim: The aim of the study is to present Nordic standardized incidence ratios (SIRs) for alcohol and tobacco related cancer by occupation, after adjustment for alcohol and tobacco, and to compare to the unadjusted SIRs. Material and Methods: The study is based on the Nordic Occupational Cancer (NOCCA) database. We used confirmatory factor analysis models for simultaneous analysis of the cancer sites related to alcohol and tobacco, to obtain factors that allow for computation of adjusted expected numbers from the reference rates. We then calculated adjusted SIRs for the relevant cancer sites for each occupation. Results: For some occupations and cancers, the changes of risk estimates were striking, from significantly high to significantly low and vice versa. Among Nordic farmers, unadjusted SIRs for cancer of the mouth and oesophagus were 0.56 (95% confidence interval (CI) 0.51⁻0.61) and 0.67 (CI 0.63⁻0.70), respectively. After adjustment, estimates changed to 1.10 (CI 1.01⁻1.21) and 1.16 (CI 1.10⁻1.22). Unadjusted SIR for pharynx cancer among wood workers was 0.83 (CI 0.75⁻0.91), adjusted SIR was 1.14 (CI 1.03⁻1.25). For larynx cancer, results in the opposite direction were seen: unadjusted SIR for economically inactive was 1.38 (CI 1.31⁻1.46) while the adjusted SIR was 0.91 (CI 0.86⁻0.96). Conclusions: Adjustment for the latent indicators of alcohol and tobacco consumption changed risk estimates for several occupations, gave a less confounded description of risk, and may guide in the identification of true risk factors.

Comparison of cancer incidence in Australian farm residents 45 years and over, compared to rural non-farm and urban residents - a data linkage study

BACKGROUND

It is not known if the incidence of common cancers in Australian farm residents is different to rural non-farm or urban residents.

METHODS

Data from farm, rural non-farm and urban participants of the 45 and Up Study cohort in New South Wales, Australia, were linked with state cancer registry data for the years 2006-2009. Directly standardised rate ratios for cancer incidence were compared for all-cancer, prostate, breast, colorectal cancer, melanoma and non-Hodgkin Lymphoma (NHL). Proportional hazards regression was used to generate incidence hazard ratios for each cancer type adjusted for relevant confounders.

RESULTS

Farm women had a significantly lower all-cancer hazard ratio than rural non-farm women (1.14, 1.01-1.29). However, the lower all-cancer risk observed in farm men, was not significant when compared to rural non-farm and urban counterparts. The all-cancer adjusted hazard ratio for combined rural non-farm and urban groups compared to farm referents, was significant for men (1.08,1.01-1.17) and women (1.13, 1.04-1.23). Confidence intervals did not exclude unity for differences in risk for prostate, breast, colorectal or lung cancers, NHL or melanoma. Whilst non-significant, farm residents had considerably lower risk of lung cancer than other residents after controlling for smoking and other factors.

CONCLUSIONS

All-cancer risk was significantly lower in farm residents compared to combined rural non-farm and urban groups. Farm women had a significantly lower all-cancer adjusted hazard ratio than rural non-farm women. These differences appeared to be mainly due to lower lung cancer incidence in farm residents.

Cancer incidence in a cohort of Swedish chimney sweeps, 1958-2006

OBJECTIVES

We examined cancer incidence in an expanded cohort of Swedish chimney sweeps.

METHODS

We added male chimney sweep trade union members (1981-2006) to an earlier cohort (employed 1918-1980) and linked them to nationwide registers of cancer, causes of deaths, and total population. The total cohort (n = 6320) was followed from 1958 through 2006. We estimated standardized incidence ratios (SIRs) using the male Swedish population as reference. We estimated exposure as years of employment and analyzed for exposure-response associations by Poisson regression.

RESULTS

A total of 813 primary cancers were observed versus 626 expected (SIR = 1.30; 95% confidence interval = 1.21, 1.39). As in a previous follow-up, SIRs were significantly increased for cancer of the esophagus, liver, lung, bladder, and all hematopoietic cancer. New findings included significantly elevated SIRs for cancer of the colon, pleura, adenocarcinoma of the lung, and at unspecified sites. Total cancer and bladder cancer demonstrated positive exposure-response associations.

CONCLUSIONS

Exposure to soot and asbestos are likely causes of the observed cancer excesses, with contributions from adverse lifestyle factors. Preventive actions to control work exposures and promote healthier lifestyles are an important priority.

Comparative mortality ratios of cancer among men in Greece across broad occupational groups

AIM

The purpose of this study was to compare site-specific cancer death rates in male workforce across major occupational groups in Greece.

METHODS

Data on cancer mortality in men aged 25-69 years during the period 2000-2005 were obtained from National Statistical Service of Greece. Age- and site (ICD-10)-specific cancer death rates and the ratio of standardized cancer death rates (i.e. the comparative mortality ratio and 95% confidence interval) across seven major occupational groups (ISCO-88) were calculated.

RESULTS

The proportion of total deaths due to cancer was ranged between 6.6, 24.3, 37.4, and 39.4% for the age groups of 15-39, 40-49, 50-59, and 60-69 years, respectively. Respiratory and gastrointestinal malignancies constituted 70% of the total cancer mortality in our population. Groups of elementary occupations, skilled agricultural workers, and plant workers showed very high mortality ratios of respiratory cancer while low ratios were found for the groups of professionals, legislators, senior officials, and managers and paradoxically for craft and related workers. Compared to the other groups, skilled agricultural and elementary groups showed higher rates of gastrointestinal and other or no determined malignancies in the age groups of 40-49 and 50-59 years old. Plant workers and machine operators/assemblers exhibited high mortality rates for most cancer sites especially in the elders group (60-69 years) and a mortality ratio of genitourinary cancer that differed significantly compared to any other group.

CONCLUSIONS

Up to 3.5-fold variations were found in site-specific cancer mortality ratios among men in Greece across broad occupational groups. The extent of the variation attributed to specific socioeconomic and/or occupational factors could not be estimated in the current study but the observed differences might stimulate thinking and preventive actions as well as point to potential hypotheses to pursue using research methods in which job and life related factors should be directly measured and controlled.

Foreword: Implementing cancer prevention in Europe

The understanding of risk factors underpinning the aetiology of many common cancers is well established, yet the conversion of this knowledge into prevention lags considerably behind. The title of this Special Issue - Implementing cancer prevention in Europe - captures the central theme within; namely, the translation of cancer epidemiology into public health policy. The Special Issue is supported by focused evidence-based case studies of how these processes might be best taken forward.