Incidence of cancer among male waiters and cooks: two Norwegian cohorts

Occupational variation in incidence of oropharyngeal cancer in the Nordic countries

PURPOSE

Evaluate the occupational variation in incidence of oropharyngeal cancer (OPC).

METHODS

We calculated standardized incidence ratios (SIRs) of OPC in occupational categories in the Nordic countries relative to the entire national populations. The data covered 6155 OPC cases.

RESULTS

Among men high risk of OPC was observed, among else, in waiters (SIR 6.28, 95% CI 4.68-8.26), beverage workers (SIR 3.00, 95% CI 1.72-4.88), and artistic workers (SIR 2.97, 95% CI 2.31-3.76). Among women high risk of OPC was observed in waiters (SIR 2.02, 95% CI 1.41-2.81) and packers (SIR 1.73, 95% CI 1.07-2.64). The lowest SIRs were observed in female gardeners (SIR 0.27, 95% CI 0.12-0.51) and male farmers (SIR 0.30, 95% CI 0.25-0.35).

CONCLUSION

The 20-fold variation in incidence of OPC between occupations needs further investigation in studies with detailed information on occupational and non-occupational risk factors.

Lifelong differences in cancer incidence and mortality between subgroups of similar socioeconomic status in the Royal Norwegian Navy

OBJECTIVES

In a previous cohort study of 28 300 Navy servicemen, vessel crews showed higher cancer incidence and mortality than did land-based personnel. We have extended the follow-up to look for changes in cancer risk, and to explore temporal trends in cancer incidence and cancer mortality during more than six decades of follow-up.

METHODS

Cancer incidence and total cancer mortality were compared with the general population by calculating standardised ratios (standardised incidence ratios (SIRs), standardised mortality ratios) for the entire follow-up, with temporal trends through seven consecutive 10-year time spans from individual entry to follow-up. Rates were compared between the subgroups using Poisson regression, expressed as rate ratios (RRs).

RESULTS

Cancer incidence in Navy servicemen suggested a healthy soldier effect limited to the first three decades of follow-up and confined to land-based personnel. Overall, vessel crews showed 13% higher cancer incidence and 36% higher cancer mortality than other Navy servicemen. Some of the differences may be explained by a higher risk in vessel crews of cancers known to have less than 25% 5-year relative survival (RR=1.71), such as cancers of the lung, liver, pancreas and mesothelioma.

CONCLUSION

Through most of the observation time, vessel crews had an overall cancer SIR that was higher than that of land-based personnel. Much of this excess involved cancers with a generally poor prognosis, linked to lifestyle and work environment. The contrasts in cancer incidence and mortality between the two subgroups of Navy servicemen persisted through more than six decades.

Head and neck cancer risk factors in the French West Indies

OBJECTIVES

The incidence of head and neck squamous cell carcinoma (HNSCC) in the French West Indies (FWI) is relatively high, despite a low prevalence of tobacco smoking and alcohol drinking. Little is known about other risk factors in the FWI. We assessed associations between several factors and HNSCC risk, their population attributable fractions (PAF) in the FWI, and compared these PAFs by subsite, sex and age.

MATERIALS AND METHODS

We conducted a population-based case-control study (145 cases and 405 controls). We used logistic regression models to estimate adjusted odds-ratios (OR), PAFs and their 95% confidence intervals (CI).

RESULTS

Tobacco smoking, alcohol drinking, high-risk HPV, family history of HNC, low BMI and several occupations and industries were significantly associated to the occurrence of HNSCC. The majority of HNSCC cases were attributable to tobacco smoking (65.7%) and alcohol (44.3%). The PAF for the combined consumption of tobacco and/or alcohol was 78.2% and was considerably larger in men (85%) than in women (33%). The PAFs for the remaining risk factors were 9% for family history of HNSCC, 9% for low BMI, 15% for high-risk HPV, and 25% for occupations. The overall PAF for all risk factors combined was 89.0% (95% CI = 82.0-93.2). The combined PAFs by sex were significantly greater in men (93.4%, 95% CI = 87.5-96.5) than in women (56.4%, 95% CI = 18.7-76.6).

CONCLUSION

Tobacco and alcohol appeared to have the greatest impact on HNSCC incidence among the studied risk factors, especially among men. Prevention programs for HNSCC in the FWI should target tobacco and alcohol cessation, particularly in men. Future research should emphasise on the role of occupational factors to better understand this disease.

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.

Adjustment for tobacco smoking and alcohol consumption by simultaneous analysis of several types of cancer

PURPOSE

Tobacco smoking and alcohol consumption are risk factors for several types of cancer and may act as confounders in aetiological studies. Large register-based cohorts often lack data on tobacco and alcohol. We present a method for computing estimates of cancer risk adjusted for tobacco and alcohol without exposure information.

METHODS

We propose the use of confirmatory factor analysis models for simultaneous analysis of several cancer sites related to tobacco and alcohol. In the analyses, the unobserved pattern of smoking habits and alcohol drinking is considered latent common factors. The models allow for different effects on each cancer site, and also for appropriate latent site-specific factors for subgroup variation. Results may be used to compute expected numbers of cancer from reference rates, adjusted for tobacco smoking and alcohol consumption. This method was applied to results from a large, published study of work-related cancer based on census data (1970) and 21 years of cancer incidence data from the national cancer registry.

RESULTS

The results from our analysis were in accordance with recognised risks in selected occupational groups. The estimated relative effects from tobacco and alcohol on cancer risk were largely in line with results from Nordic reports. For lung cancer, adjustment for tobacco implied relative changes in SIR between a decrease from 1.16 to 0.72 (Fishermen), and an increase from 0.47 to 0.95 (Forestry workers).

CONCLUSIONS

We consider the method useful for achieving less confounded estimates of cancer risk in large cohort studies with no available information on smoking and alcohol consumption.

Lung cancer risk among cooks when accounting for tobacco smoking: a pooled analysis of case-control studies from Europe, Canada, New Zealand, and China

OBJECTIVES

To investigate the risk of lung cancer among cooks, while controlling for smoking habits.

METHODS

We used data from the SYNERGY project including pooled information on lifetime work histories and smoking habits from 16 case-control studies conducted in Europe, Canada, New Zealand, and China.

RESULTS

Before adjustment for smoking, we observed an increased risk of lung cancer in male cooks, but not in female cooks. After adjusting, there was no increased risk and no significant exposure-response relationship. Nevertheless, subgroup analyses highlighted some possible excess risks of squamous cell carcinoma and small cell carcinoma in female cooks.

CONCLUSIONS

There is evidence that lung cancer risks among cooks may be confounded by smoking. After adjustment, cooks did not experience an increased risk of lung cancer overall. The subgroup analyses showing some excess risks among female cooks require cautious interpretation.

Cancer incidence among waiters: 45 years of follow-up in five Nordic countries

AIMS

To study cancer risk patterns among waiters in the Nordic countries.

METHODS

We identified a cohort of 16,134 male and 81,838 female waiters from Denmark, Finland, Iceland, Norway and Sweden. During the follow-up period from 1961 to 2005, we found that 19,388 incident cancer cases were diagnosed. Standardised incidence ratio (SIR) was defined as the observed number of cancer cases divided by the expected number, based on national age, time period and gender-specific cancer incidence rates in the general population.

RESULTS

The SIR of all cancers in waiters, in the five countries combined, was 1.46 (95% CI 1.41-1.51) in men and 1.09 (1.07-1.11) in women. In male waiters, the SIR decreased from 1.79 (1.63-1.96) in 1961-1975, to 1.33 (1.26-1.40) in 1991-2005, but remained stable among women. The SIR among male waiters was highest for cancers in the pharynx (6.11; 95% CI 5.02-7.37), oral cavity (4.91; 95% CI 3.81-6.24) and tongue (4.36; 95% CI 3.13-5.92); and in female waiters, in the larynx (2.17; 95% CI 1.63-2.82), oral cavity (1.96; 95% CI 1.60-2.34) and lung (1.89; 95% CI 1.80-1.99).

CONCLUSIONS

The risk of cancer among waiters was higher than in the general population. The elevated incidence in some cancer sites can likely be explained by higher alcohol consumption, the prevalence of smoking and occupational exposure to tobacco smoke. Hopefully, the incidence of cancer among waiters will decrease in the future, due to the banning of tobacco smoking in restaurants and bars in the Nordic countries.

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

Knowledge of cancer risk according to occupational affiliation is an essential part of formatting preventive actions aimed at the adult population. Herein, data on 10 major cancer sites amenable by life style exposures from the Nordic Occupational Cancer Study (NOCCA) are presented. All subjects aged 30-64 years participating in one or more national censuses in Denmark, Finland, Iceland, Norway, or Sweden between 1960 and 1990 were included in the cohort and followed up for cancer from inclusion until 2003/2005 via a linkage with the national cancer registries, and standardised incidence ratios (SIRs) were computed. Variation in risk across occupations was generally larger in men than in women. In men, the most consistent cluster with high risk of numerous cancer types included waiters, cooks and stewards, beverage workers, seamen, and chimney sweeps. Two clusters of occupations with generally low cancer risks were seen in both men and women. The first one comprised farmers, gardeners, and forestry workers, the second one included groups with high education, specifically those in health and pedagogical work. Although cancer risk varies by occupation, only a smaller part of the variation can be attributed to occupational exposures in the strict sense. Preventive measures at the work place are important to avoid established and new occupational health hazards. This study also indicates that the work place in addition should be seen as a useful arena for reaching groups of adults with more or less similar habits and attitudes for general health promotion.

The precancerous effect of emitted cooking oil fumes on precursor lesions of cervical cancer

Although cooking emission from high-temperature frying has been deemed a Group 2A carcinogen by the International Agency for Research on Cancer, little is known about its impact on cervical tumorigenesis. To investigate the precancerous consequence of cooking oil fumes on cervical intraepithelial neoplasm (CIN), a community-based case-control study, which takes all known risk factors into consideration, was conducted in Taiwan. From 2003 to 2008, in a Pap smear screening and biopsy examination network, 206 pathology-verified women with inflammations/atypical squamous cells of undetermined significance or CIN grade-1 (CIN1) and 73 with CIN2-3 (defined as low-grade squamous intraepithelial lesions (LGSIL) and high-grade squamous intraepithelial lesions (HGSIL), respectively); and 1,200 area-and-age-matched controls with negative cytology were recruited. Multinomial logistic regression was applied in the multivariate analysis to determine the likelihood of contracting LGSIL or HGSIL. The risks of the two lesions increased with the increase of carcinogenic high-risk human papillomavirus DNA load, with a clear dose-response relationship. Chefs were observed to experience a 7.9-fold elevated HGSIL risk. Kitchens with poor fume ventilation during the main cooking life-stage correlated to a 3.7-fold risk of HGSIL, but not for LGSIL. More than 1 hr of daily cooking in kitchens with poor fume conditions appeared to confer an 8.4-fold HGSIL risk, with an 8.3-fold heterogeneously higher odds ratio than that (aOR = 1.0) for LGSIL. Similar risk pattern has been reproduced among never-smoking women. Our findings demonstrate the association between indoor exposure to cooking fumes from heated oil and the late development of cervical precancerous lesions. This final conclusion needs to be verified by future research.

Indoor ultrafine particles and childhood asthma: exploring a potential public health concern

Exposure to airborne particulate matter has a negative effect on respiratory health in both children and adults. The ultrafine fraction of particulate air pollution is of particular interest because of its increased ability to cause oxidative stress and inflammation in the lungs. We reviewed the literature, and to date findings suggest that ultrafine particles (UFPs) may play an important role in triggering asthma symptoms. Furthermore, we believe that indoor UFP exposures may be particularly important because people spend the majority of their time indoors where sources of these contaminants are often present. While several epidemiological studies have examined the respiratory effects of ambient UFP exposures, the relationship between indoor UFP exposures and childhood asthma has yet to be examined in clinical or epidemiological studies. However, the portable instrumentation necessary to conduct such investigations is increasingly available, and we expect that this issue will be addressed in the near future. Therefore, the aim of this article is to provide a general review of UFP toxicity as related to childhood asthma in order to draw attention to a potentially important public health concern.

PRACTICAL IMPLICATIONS

A number of indoor sources of ultrafine particles (UFPs) have been identified, but the health effects of indoor UFP exposures remain largely unexplored. The potential respiratory effects of such exposures seem most concerning because these particles are known to cause oxidative stress and inflammation in the lungs. Subsequently, indoor UFP exposures may contribute to the exacerbation of asthma symptoms in susceptible individuals. This paper provides a review of UFP toxicity as related to childhood asthma, and to date evidence suggests that further investigation into the respiratory effects of indoor UFP exposures is warranted.

Deaths from nasopharyngeal cancer among waiters and waitresses in Chinese restaurants

OBJECTIVE

Previous studies have shown that waiters have a high risk of developing cancers of the buccal cavity and pharynx, but nasopharyngeal cancer (NPC) has not been specifically studied. This study was carried out to investigate whether waiters/waitresses in Chinese restaurants have an increased risk of dying from NPC.

METHODS

A mortality odds ratio study was used to estimate the relative risk of dying from NPC for waiters/waitresses working in Chinese restaurants in Hong Kong during the period 1986-1995, using the general population as the external comparison group and deceased kitchen workers as an internal comparison group. Cases were deaths from NPC and the controls were deaths from the selected sets of reference causes.

RESULTS

Seventeen deaths from NPC were identified among 415 deceased waiters and four NPC deaths occurred among 140 deceased waitresses. The adjusted mortality odds ratio (aMOR) for NPC was increased among waiters, being 3.02 (95% CI 1.82-5.00) and 2.61 (95% CI 1.02-6.69) in the external and internal comparisons, respectively. For waitresses, the aMOR was 4.58 (95% CI 1.63-12.86) in the external comparison. Analysis by duration of union membership suggested a dose-response relationship.

CONCLUSIONS

An increased risk of dying from NPC was observed among waiters/waitresses and could not be fully explained by bias or confounding factors. Possible risk factors related to poor indoor air quality in the service areas of Chinese restaurants in Hong Kong should be further investigated.

Respiratory health effects of exposure to environmental tobacco smoke

Tobacco smoke is a major component of indoor air pollution. Exposure to environmental tobacco smoke (ETS) is prevalent worldwide despite growing awareness of its adverse health effects on non-smokers. ETS contains the same toxic substances as identified in mainstream tobacco smoke. Cotinine (a metabolite of nicotine) can be measured in urine and serum of non-smokers exposed to ETS and reflects the degree of exposure. In children, exposure to ETS leads to reduced lung function, increased risk of lower respiratory tract illnesses, acute exacerbation of asthma resulting in hospitalization, increased prevalence of non-allergic bronchial hyperresponsiveness, increased risk for sudden infant death syndrome (SIDS) and possibly increased risk for asthma. Exposure to ETS is responsible for excess cost to the family's financial resources and demands on health services. In adults, exposure to ETS is associated with increased risk of lung cancer, particularly in those with high exposure and acute and chronic respiratory symptoms that improve after the cessation of exposure. Healthcare providers should advocate for non-smokers' rights in the community and support legislation to limit tobacco exposure.

The importance of marital and socioeconomic status in incidence and survival of prostate cancer. An analysis of complete Norwegian birth cohorts

BACKGROUND

Previous studies of the association between social and family status and prostate cancer (PCa) have given somewhat divergent results. Little attention has been paid to the possible importance of these factors for survival.

METHODS

In this study, hazard regression models for PCa incidence and mortality were estimated on the basis of register- and census-based histories for complete Norwegian birth cohorts, giving a follow-up time of 16 million person years and 30,000 cases of PCa.

RESULTS

A significant excess incidence of about 20% was found for ever-married men and for those with higher education. Marriage and socioeconomic resources appeared, however, to have a favorable effect on survival. Five-year relative survival from metastasized cancer among men with a high educational level was found to be 15 percentage points higher than among men with lower education.

CONCLUSIONS

The observed differences in incidence are not easily explained. They apparently run counter to the hypothesis that multiple partners give a higher PCa risk, but may be consistent with the view that fat and meat consumption is risky. Better survival from PCa in higher socioeconomic groups and among married men may reflect differences in the search for, access to, or quality of treatment or a better constitution to fight the disease.

Heavy drinking in the restaurant business: the role of social modelling and structural factors of the work-place

The role of social modelling and structural factors of the work-place in predicting the probability of heavy drinking was investigated in a sample of 3267 Norwegian male and female waiters and cooks. In the logistic regression analysis, the probability of heavy drinking was increased by two social modelling factors and one structural factor. Having co-workers who, at least weekly, took an end-of-work drink at the work-place gave an odds ratio for heavy drinking of 2.8 (95% CI 1.9-4.1), and having co-workers who went out after work at least every week gave an odds ratio of 1.8 (95% CI 1.2-2.8). Working at a place with a liberal alcohol policy gave an odds ratio 1.5 (95% CI 1.1-2.2). Among the background factors, only household type significantly predicted heavy drinking. As compared with living with children, the odds for heavy drinking when living alone was 4.3 (95% CI 2.9-6.4). The results indicate that preventive measures in the restaurant business should not only concentrate on the individual, but also deal with factors related to the occupational activity that promote and sustain heavy drinking.

Cohorts and privacy

The extent to which major cohort studies now rely on centralized machine-readable files of personal records is taken largely for granted by investigators, but not by the public, privacy advocates, politicians, or the popular press. When widespread linkage into personal histories for statistical studies was first envisaged a few decades ago, it was regarded as impractical. But privacy advocates now fear the statistical uses even more than the administrative applications, perhaps because the latter are inevitable to prevent abuses, and often are associated with monetary benefits or personal convenience. Indeed a concept of 'privacy' has arisen that is deemed to be violated even in statistical studies where confidentiality is assured, unless the particular purpose is approved by all individuals. This concept motivates much of the political thinking. What could be lost to preventive medicine and clinical testing by this is illustrated with data from cohort studies reported in this journal (CCC) in 1993.

Cancer incidence among waitresses in Norway

Previous studies have found high risk of cancers of the upper aerogastric tract, liver, and lung among waiters. Since approximately 75 percent of those working in the restaurant business in Norway are women, we have analyzed cancer incidence in a cohort of waitresses, to determine whether they have the same high cancer-risk as their male colleagues. The cohort consisted of 5,314 waitresses organized in the Restaurant Workers' Union between 1932 and 1978. The follow-up period was from 1959 to 1991. The standardized incidence ratio (SIR) for all causes of cancer was 1.0 (95 percent confidence interval [CI] = 0.9-1.1), based on 430 observed cases. Cancers of the tongue, mouth, pharynx, larynx, esophagus, and liver were grouped together as alcohol-associated cancers. SIR for these cancers combined was 1.1 (CI = 0.5-2.2). For lung cancer, SIR was 2.3 (CI = 1.6-3.1). Cervical cancer was also more frequent than expected, and breast cancer less frequent than expected. The larger excess of lung cancer and cervical cancer appeared in the sub-cohort working in restaurants with a license to serve alcohol. No excess risk of alcohol-associated cancers could be detected in this cohort of Norwegian waitresses. A longer follow-up period will be necessary to evaluate possible consequences of an increased alcohol consumption among younger waitresses. Waitresses in Norway are, like their male colleagues, at high risk for lung cancer.