Occupational exposures and risk of esophageal and gastric cardia cancers among male Swedish construction workers

Occupational asbestos exposure and risk of esophageal cancer: A systematic review and meta-analysis

Esophageal cancer (EC), which includes squamous cell carcinoma (ESCC) and adenocarcinoma (EAC), is an important cancer with poor prognosis and high mortality rate. Several occupational exposures have been associated with EC. We aim to investigate the association between occupational asbestos exposure and EC risk, considering types of asbestos and histology of the disease. We included studies mentioned in the list of references in previous reviews and pooled analyses, and we conducted an independent search in PubMed and Scopus. Forest plots of relative risks (RR) were constructed based on the association between occupational asbestos and EC risk. Random-effects models were used to address heterogeneity between 48 independent cohort and case-control studies. We found an association between occupational asbestos exposure and EC (meta-relative risk [RR] = 1.20, 95% confidence interval [CI] = 1.09-1.32; I2 = 58.8%, p-heterogeneity [het] <.001). The results of stratification by job (p-het = .20) indicate an increased RR among asbestos product workers (RR = 1.39, 95% CI = 1.07-1.81), asbestos applicators (RR = 1.41, 95% CI = 1.20-1.67), and construction workers (RR = 1.12, 95% CI = 1.02-1.24). There was no heterogeneity in meta-RR according to outcome (p = .29), geographic region (p = .69), year of publication (p = .59), quality score (p = .73), asbestos type (p = .93), study design (p = .87), and gender (p = .88), control for potential confounders (p = .20), year of first employment (p = .94) and exposure level (p = .43). The stratification analysis by histology type found an increased RR for both ESCC 1.33(1.03-1.71) and EAC 1.45(1.03-2.04) (p-het = .68). We didn't find evidence of publication bias (p = .07). The results of our study suggest that occupational asbestos exposure is associated with an increased risk of EC in both histology types.

Exposure to construction dust and health impacts - A review

Construction dust contributes a significant proportion of airborne particulate matter, affecting the health of its surrounding environment and population. Construction workers are normally exposed to dust at high levels and bear severe health risks. The existing articles concerning the exposure and health impacts of construction dust are limited, but this research field has received more and more attention. This work reviews literature in the field and tries to systematically assess the current research state. Here, we review (1) methods used to monitor or sample construction dust; (2) main characteristics of construction dust, including dust classification, exposed populations, and exposure concentrations; (3) potential health hazards and (4) health risk assessment of construction dust. From existing literature, the exposure concentrations of different types and sources of construction dust are usually the focus of attention, while its particle size distribution and chemical composition are rarely mentioned. The classification and characteristics of populations exposed to construction dust ought to be a key consideration but not clear enough so far. There still lacks in-depth study of health hazards and systematic assessment of risks associated with construction dust. In future, it is valuable to develop utility instruments to precisely monitor construction dust. Besides, control means to reduce the pollution of construction dust deserve more studies. Health hazards of construction dust should be verified by biological experiments. Moreover, emerging algorithm models should be utilized in the risk assessment. The findings will help gain a better understanding of construction dust exposure and associated health risks.

Derivatives of Plastics as Potential Carcinogenic Factors: The Current State of Knowledge

Simple Summary

Nowadays, micro- and nanoplastic particles can be found almost everywhere, being especially harmful for humans. Their absorption, primarily via inhalation and digestive routes, might lead to a particularly dangerous accumulation of those substances within the human body. Due to the alarming increase in contamination worldwide and excessive production of plastics and synthetic materials, there is an urgent need to investigate the effects of those substances on human health. So far, it has been observed that nano- and microplastics might be extremely harmful, leading to serious health conditions, such as cancers of various human body systems.

Abstract

Micro- and nanoplatics have been already reported to be potential carcinogenic/mutagenic substances that might cause DNA damage, leading to carcinogenesis. Thus, the effects of micro- and nanoplastics exposure on human health are currently being investigated extensively to establish clear relationships between those substances and health consequences. So far, it has been observed that there exists a definite correlation between exposure to micro- and nanoplastic particles and the onset of several cancers. Therefore, we have conducted research using PubMed, Web of Science, and Scopus databases, searching for all the research papers devoted to cancers that could be potentially related to the subject of exposure to nano- and microplastics. Ultimately, in this paper, we have discussed several cancers, including hepatocellular carcinoma, pancreatic cancer, pancreatic ductal adenocarcinoma, biliary tract cancer, and some endocrine-related cancers.

Endocrine disruptors of sex hormone activities

Sex hormones, such as androgens, estrogens and progestins are naturally occurring compounds that tightly regulate endocrine systems in a variety of living organisms. Uncontrolled environmental exposure to these hormones or their biological and synthetic mimetics has been widely documented. Furthermore, water contaminants penetrate soil to affect flora, fauna and ultimately humans. Because endocrine systems evolved to respond to very small changes in hormone levels, the low levels found in the environment cannot be ignored. The combined actions of sex hormones with glucocorticoids and other nuclear receptors disruptors creates additional level of complexity including the newly described "dynamic assisted loading" mechanism. We reviewed the extensive literature pertaining to world-wide detection of these disruptors and created a detailed Table on the development and current status of methods used for their analysis.

Geophagia and risk of squamous cell esophageal cancer in the African esophageal cancer corridor: Findings from the ESCCAPE multicountry case-control studies

Geophagia, the intentional practice of consuming soil, occurs across the African esophageal cancer corridor, particularly during pregnancy. We investigated whether this practice is linked to endemic esophageal squamous cell carcinoma (ESCC) in this region. We conducted ESCC case-control studies in Tanzania, Malawi and Kenya. Cases were patients with incident histologically/clinically confirmed ESCC and controls were hospital patients/visitors without digestive diseases. Participants were asked if they had ever eaten soil (never/regularly/pregnancy-only). Odds ratios (OR) are adjusted for sex, age, tobacco, alcohol, country, religion and marital status. Overall, 934 cases (Malawi 535, Tanzania 304 and Kenya females 95) and 995 controls provided geophagia information. Among controls, ever-geophagia was common in women (Malawi 49%, Kenya 43% and Tanzania 29%) but not in men (10% Malawi, <1% Tanzania). In women, ESCC ORs were 1.25 (95% CI: 0.70, 2.22) for regular versus never geophagia and 0.88 (95% CI: 0.64, 1.22) for pregnancy-only versus never. Findings were stronger based on comparisons of cases with hospital visitor controls and were null using hospital patients as controls. In conclusion, geophagia is too rare to contribute to the male ESCC burden in Africa. In women, the practice is common but we did not find consistent evidence of a link to ESCC. The study cannot rule out selection bias masking modest effects. Physical effects of geophagia do not appear to have a large impact on overall ESCC risk. Research with improved constituent-based geophagia exposure assessment is needed.

Critical review of the evidence for a causal association between exposure to asbestos and esophageal cancer

Esophageal cancers comprise about 1% of all cancers diagnosed in the US but are more prevalent in other regions of the world. Several regulatory agencies have classified asbestos as a known human carcinogen, and it is linked to multiple diseases and malignancies, including lung cancer and mesothelioma. In a 2006 review of the epidemiological literature, the Institute of Medicine (IOM) did not find sufficient evidence to demonstrate a causal relationship between asbestos exposure and esophageal cancer. To reevaluate this conclusion, we performed a critical review of the animal toxicological, epidemiological, and mechanism of action literature on esophageal cancer and asbestos, incorporating studies published since 2006. Although there is some evidence in the epidemiological literature for an increased risk of esophageal cancer in asbestos-exposed occupational cohorts, these studies generally did not control for critical esophageal cancer risk factors (e.g. smoking, alcohol consumption). Furthermore, data from animal toxicological studies do not indicate that asbestos exposure increases esophageal cancer risk. Based on our evaluation of the literature, and reaffirming the IOM's findings, we conclude that there is insufficient evidence to demonstrate a causal link between asbestos exposure and esophageal cancer.

Cancer Risk Associated With Exposure to Bitumen and Bitumen Fumes: An Updated Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate whether cancer risks are increased among bitumen (asphalt) workers.

METHODS

Systematic review and meta-analysis of cancer risks (lung, upper aerodigestive tract (UADT), esophagus, bladder, kidney, stomach, and skin) and bitumen exposure. Certainty in the epidemiological evidence that bitumen-exposed workers experience increased cancer risks was rated using Grading of Recommendations Assessment, Development and Evaluation criteria.

RESULTS

After excluding lower-quality studies, lung cancer risks were not increased among bitumen-exposed workers (meta-relative risk [RR] 0.94, 95% CI 0.74 to 1.20, eight studies). Increased risks of UADT and stomach cancers were observed (meta-RR 1.31, 95% CI 1.03 to 1.67, 10 studies and meta-RR 1.29, 95% CI 1.03 to 1.62, seven studies, respectively).

CONCLUSIONS

Except for lung cancer, evidence for increased cancer risks among bitumen-exposed workers was judged to be of low certainty, due to inadequate exposure characterization and unmeasured confounders (coal tar exposure, smoking, and alcohol consumption).

Ingested asbestos in filtered beer, in addition to occupational exposure, as a causative factor in oesophageal adenocarcinoma

Oesophageal adenocarcinoma has become much more common over the past 50 years, particularly in Britain, with an unexplained male to female ratio of > 4:1. Given the use of asbestos filtration in commercial brewing and reports of its unregulated use in British public houses in the 1970's to clear draught beer "slops", we have assessed the hypothesis that ingested asbestos could be a causative factor for this increased incidence. Importantly, occupational asbestos exposure increases the risk of adenocarcinoma but not squamous cell carcinoma of the oesophagus. The presence of asbestos fibres was consistently reported in filtered beverages including beers in the 1970s and asbestos bodies have been found in gastrointestinal tissue, particularly oesophageal tissue, at autopsy. There is no reported association between the intake of alcohol and oesophageal adenocarcinoma but studies would mostly have missed exposure from draught beer before 1980. Oesophageal adenocarcinoma has some molecular similarities to pleural mesothelioma, a condition that is largely due to inhalation of asbestos fibres, including predominant loss of tumour suppressor genes rather than an increase of classical oncogenic drivers. Trends in incidence of oesophageal adenocarcinoma and mesothelioma are similar, rising rapidly over the past 50 years but now plateauing. Asbestos ingestion, either from beer consumed before around 1980, or from occupational exposure, seems a plausible causative factor for oesophageal adenocarcinoma. If this is indeed the case, its incidence should fall back to a low baseline by around 2050.

Systematic review: the etiology of esophageal squamous cell carcinoma in low-income settings

Esophageal carcinoma causes over 380 000 deaths per year, ranking sixth worldwide in mortality amongst all malignancies. Globally, the squamous cell subtype is most common and accounts for 80% of esophageal cancers. Nonetheless, esophageal squamous cell carcinoma is much more poorly understood than esophageal adenocarcinoma, including what is driving such high prevalences, why it often presents in young patients, and shows such marked geographical delineations Areas covered: The current literature was searched for articles focusing on aetiopathogenesis of squamous cell esophageal carcinoma via a systematic review, particularly in low-resource settings. This was supplemented by papers of interest known to the authors. Expert commentary: Current putative mechanisms include polycyclic aromatic hydrocarbons, nitrosamines, acetaldehyde, cyclo-oxygenase-2 pathways, androgen and their receptor levels, as well as smoking & alcohol, micronutrient deficiencies and diet, mycotoxins, thermal damage, oral hygiene and microbiotal factors, inhaled smoke, viral infections such as HPV, and chronic irritative states. Etiology is likely multifactorial and varies geographically. Though smoking and alcohol play a predominant role in high-income settings, there is strong evidence that mycotoxins, diet and temperature effects may play an under-recognized role in low and middle-income settings.

Potential Health Risk of Endocrine Disruptors in Construction Sector and Plastics Industry: A New Paradigm in Occupational Health

Endocrine disruptors (EDs) belong to large and diverse groups of agents that may cause multiple biological effects associated with, for example, hormone imbalance and infertility, chronic diseases such as diabetes, genome damage and cancer. The health risks related with the exposure to EDs are typically underestimated, less well characterized, and not regulated to the same extent as, for example, carcinogens. The increased production and utilization of identified or suspected EDs in many different technological processes raises new challenges with respect to occupational exposure settings and associated health risks. Due to the specific profile of health risk, occupational exposure to EDs demands a new paradigm in health risk assessment, redefinition of exposure assessment, new effects biomarkers for occupational health surveillance and definition of limit values. The construction and plastics industries are among the strongest economic sectors, employing millions of workers globally. They also use large quantities of chemicals that are known or suspected EDs. Focusing on these two industries, this short communication discusses: (a) why occupational exposure to EDs needs a more specific approach to occupational health risk assessments, (b) identifies the current knowledge gaps, and (c) identifies and gives a rationale for a future occupational health paradigm, which will include ED biomarkers as a relevant parameter in occupational health risk assessment, surveillance and exposure prevention.

Occupational exposure to crystalline silica and gastric cancer: a systematic review and meta-analysis

Crystalline silica is a widely used industrial material that is readily available worldwide, and is one of the most common types of particulate mineral pollutants. It has been classified as a group 1 human carcinogen of the respiratory system; however, whether it is linked to gastric cancer remains uncertain. We conducted a systemic review and meta-analyses to search for evidence of the relationship between gastric cancer and occupational exposure to crystalline silica. We searched for articles on occupations involving silica exposure and gastric cancer studies up to December 2014. Pooled-risk estimates of the association between occupational crystalline silica exposure and risk of gastric cancer were calculated by a random effects model. Metaregression analyses of industry type and histological confirmation status, study design and industrial subgroup analyses were performed. 29 articles, including 9 case-control and 20 cohort studies, were analysed. The overall summary effects size was 1.25 (95% CI 1.18 to 1.34) for the association of occupational silica exposure with gastric cancer. Both heterogeneity and publication bias were partially attenuated after subgroup analyses. Heterogeneity of studies was attenuated after metaregression by industry. Higher overall effects were observed in the mining and foundry industries. We found a significant relationship between occupational crystalline silica exposure and gastric cancer. Our results were strengthened by various subgroup analyses and, considering the biological plausibility of our premise, further studies are required to better understand this association.

Association between Occupational Exposure to Wood Dust and Cancer: A Systematic Review and Meta-Analysis

Objective

To perform a systematic review to analyze the association between occupational exposure to wood dust and cancer.

Methods

A systematic literature search of entries made in the MEDLINE-PubMed database between 1957 and 2013 was conducted to identify studies that had assessed the relationship between occupational exposure to wood dust and different types of cancer. A meta-analysis of selected case-control and cohort studies was subsequently performed.

Results

A total of 114 studies were identified and 70 were selected for review. Of these, 42 studies focused on the relationship between wood dust and nasal cancer (n = 22), lung cancer (n = 11), and other types of cancer (n = 9). Low-to-moderate quality evidence that wood dust acts as a carcinogen was obtained, and a stronger association between wood dust and nasal adenocarcinoma was observed. A lesser association between wood dust exposure and lung cancer was also observed. Several studies suggested that there is a relationship between wood dust and the onset of other cancers, although there was no evidence to establish an association. A meta-analysis that included four case-controls studies showed that workers exposed to wood dust exhibited higher rates of nasal adenocarcinoma than other workers (odds ratio = 10.28; 95% confidence interval: 5.92 and 17.85; P<0,0001), although a large degree of heterogeneity was found.

Conclusions

Low-to-moderate quality evidence supports a causal association between cancer and occupational exposure to wood dust, and this association was stronger for nasal adenocarcinoma than for lung cancer. There was no evidence of an association between wood dust exposure and the other cancers examined.

Occupational exposures and risk of stomach and esophageal cancers: update of a cohort of female textile workers in Shanghai, China

BACKGROUND

Associations between stomach and esophageal cancer and exposures to dusts, metals, chemicals, and endotoxin in the workplace are not very well understood, particularly in women.

METHODS

We followed 267,400 female textile workers in Shanghai, China for cancer incidence from 1989 to 2006. Stomach (n = 1374) and esophageal (n = 190) cancer cases were identified and a comparison subcohort (n = 3187) was randomly selected. Cox proportional hazard modeling was used, adjusting for age and smoking.

RESULTS

Increasing stomach cancer risk was observed with increasing duration of synthetic fiber dust exposure (p = 0.03), although the magnitude of effect was small (20 + years: HR = 1.2, 95% CI 1.1-1.4). Trends with endotoxin exposure were modestly inversed for esophageal cancer and increased for stomach cancer, but with little deviation from a null association.

CONCLUSIONS

Our findings demonstrate that long durations of synthetic fiber dust exposure can increase stomach cancer risk in women, but provide limited support for associations with other textile industry exposures.

A review and meta-analysis of cancer risks in relation to Portland cement exposure

Workers engaged in the production of Portland cement may come into contact with potential occupational hazards, but existing epidemiological studies show wide variation in risk estimates for cancer incidence and mortality in relation to cement exposure. This report identified studies of cement workers and associations with cancer incidence and mortality in a systematic review and meta-analysis. A systematic review according to the PRISMA guidelines was conducted to identify studies of Portland cement workers and cancer outcomes. Meta-analyses were performed using random effects models for all cancers combined and for each cancer site with three or more reported measures of risk. A total of 26 studies were included in the review (14 occupational cohort studies and 12 case-control studies). Overall, the meta-relative risks did not provide convincing evidence for increased risks of any cancers in relation to cement exposure. Meta-SMR and 95% CIs were 0.94 (0.76 to 1.16) for six studies reporting all cancers combined, 0.93 (0.62 to 1.39) for seven studies reporting on lung cancer, 1.07 (0.72 to 1.59) for five studies reporting on stomach cancer, and 1.05 (0.79 to 1.40) for four studies reporting on colorectal cancer. Meta-relative risks for cancer incidence were similarly null for all sites with the exception of colorectal cancer which had a borderline statistically significant elevated risk (SIR=1.38, 95% CI 1.02 to 1.88). Overall, the meta-relative risks calculated across 26 published studies do not provide evidence of increased risks for cancer in relation to cement exposure.

Risk factors for the development of oesophageal adenocarcinoma in Barrett's oesophagus: a UK primary care retrospective nested case-control study

BACKGROUND

Oesophageal adenocarcinoma (OAC) incidence is rising rapidly and prognosis remains poor. Endoscopic surveillance of Barrett's oesophagus (BO) remains controversial.

OBJECTIVE

A nested case-control study was undertaken to evaluate risk factors for progression of BO to OAC, potentially guiding surveillance efforts.

METHODS

The Health Improvement Network database includes general practitioner consultations from 5 million UK subjects. BO subjects with 1-year minimum of follow up were followed until development of OAC or end of time on database. Demographic variables (age, gender, smoking, body mass index) and data on medication considered negatively (aspirin/nonsteroidal anti-inflammatory drugs/proton pump inhibitors) or positively associated (lower oesophageal sphincter-relaxing and asthma drugs) with OAC development were studied. Cox regression analysis-derived hazard ratios with 95% confidence intervals estimated the relative risk for OAC progression.

RESULTS

A total of 3749 BO subjects were studied: 55 developed OAC during 17,743 patient years of follow up, a progression rate of 0.3% per annum. There was 96.7% of the cohort who took proton-pump inhibitors, with no association observed. Increasing age (1.03, 95% CI 1.01-1.05, p = 0.005), male gender (3.06, 95% CI 1.50-6.24, p = 0.002), and having ever smoked (2.36, 95% CI 1.13-4.93, p = 0.023) were associated with progression to OAC, (although smoking lost association on multivariate analysis). Increasing number of drugs used for asthma (2.91, 95% CI 1.10-7.68, p= 0.0314) was also associated.

CONCLUSION

In this nested case-control study of BO, male gender, increasing age, and increasing use of asthma drugs were associated with progression to OAC.

Cancer risk among patients with coal workers' pneumoconiosis in Taiwan: a nationwide population-based study

This study is aimed to evaluate the cancer risk among patients with coal workers' pneumoconiosis (CWP) using a nationwide population-based dataset. Patients without previous cancer who had been diagnosed with CWP and followed-up for more than 1 year between 1997 and 2006 were recruited from the Taiwan National Health Insurance database. Standardized incidence ratios (SIRs) of cancers in CWP patients were calculated and compared to the cancer incidence in the general population. Risk factors for cancer development were also analyzed. After a median follow-up of 9.68 years, 954 cancers developed among 8,051 recruited CWP patients, with a follow-up of 69,398 person-years. The SIR for all cancers was 1.12 [95% confidence interval (CI) 1.04-1.18]. Males older than 80 years had a SIR of 1.27 (95% CI: 1.06-1.51). The SIRs of esophageal (1.76, 95% CI: 1.24-2.44), gastric (1.42, 95% CI: 1.13-1.76), liver and biliary tract (1.18, 95% CI: 1.01-1.37) and lung and mediastinal (1.45, 95% CI: 1.26-1.66) cancers were significantly higher in the CWP group than in the general population. Multivariate analysis showed that age ≥ 60 years [hazard ratio (HR) 1.70, 95% CI: 1.41-2.05), male gender (HR = 1.79, 95% CI: 1.44-2.23) and liver cirrhosis (HR = 3.99, 95% CI: 2.89-5.51) were significant predictors of cancer development in patients with CWP. We concluded that patients with CWP, especially elderly males, were at increased risk of cancer. Age, male gender and liver cirrhosis were independent risk factors for cancer development.

Subjects with prostate cancer are less likely to develop esophageal cancer: analysis of SEER 9 registries database

Esophageal adenocarcinoma (EAC) is five times more common among men. EAC tissue exhibits an increased concentration of androgen receptors. We previously reported lower EAC incidence following prostate cancer (PC), suggesting androgen deprivation therapy may reduce EAC incidence, but were unable to demonstrate reducing incidence of EAC with time (latency effect) that would support a cumulative effect of anti-androgen treatment.The Survival Epidemiology and End Results (SEER9) dataset from 1977–2004 was therefore examined to identify subjects with a first malignant primary of PC.Subjects were followed until second primary cancer diagnosis,death, or time period end. Age- and period-adjusted standardized incidence ratios (SIR) were calculated as an estimate of relative risk of an esophageal second malignant primary. Between 1977 and 2004, 343,538 subjects (following exclusion criteria) developed PC as a first primary malignant tumor, providing 2,014,337 years of follow-up.Subsequently 604 esophageal cancers developed, with 763 expected. The incidence of EAC fell following PC [SIR0.83 (95 % CI 0.74–0.93)] with a latency effect identified with SIR 1.1 3 months to 1 year post-PC, SIR 0.85 1–5 years post-PC, and SIR 0.75 greater than five years post-PC. The incidence of esophageal squamous cell carcinoma (ESCC) after PC was also reduced [SIR, 0.79 (0.69-0.89)],with evidence of a latency effect also seen. There is a reduced risk of developing esophageal cancer, both EAC and ESCC, following PC. Androgen deprivation therapy may contribute, but changes in lifestyle following PC diagnosis and decrease in ESCC incidence are also plausible explanations.

Occupational exposure and the risk of Barrett's esophagus: a case-control study

BACKGROUND

Case-control studies in the United States and Europe have linked occupational exposure to volatile sulfur compounds, solvents, and pesticide to increased risk of esophageal adenocarcinoma. However, the association between occupational exposures and the risk of Barrett's esophagus (BE) is unclear given the absence of studies in this area.

METHODS

This is a case-control study in patients undergoing endoscopy who were either referred directly or were eligible for screening colonoscopy and recruited from primary care clinics. All participants completed a survey on (1) self-reported occupational exposures to asbestos, metal dust, organic solvents, and pesticides, and (2) self reported longest held job and job-related activities. The latter were assigned by an industrial hygienist who was blinded to the case and control status into one of 99 standard occupational categories used by the US Department of Labor. Each occupational category was then assigned an expected level of exposure to the same four classes of agents in addition to radiation. We compared the self-reported exposure and the expected occupational exposure based on the self-reported occupation between cases with definitive BE and controls without BE. We examined the associations adjusting for age, sex, race, and patient recruitment source in a multivariable logistic regression analysis.

RESULTS

We examined 226 cases of definitive BE and 1,424 controls without BE. There was a greater proportion of patients with self-reported asbestos exposure in cases than controls (16.2 % vs. 12.0 %; p = 0.08) but no significant differences in metal dust, organic solvents, or pesticides. The multivariate model did not show an independent association between self-reported asbestos exposure and BE. For the calculated occupational exposure, there were no significant differences between cases and controls for asbestos (29.6 % vs. 27.5 %; p = 0.5), metal dust, organic solvents, pesticides, or radiation exposure. Among commonly reported occupation, there were significantly greater proportion of retail sales workers in BE cases than controls (10.8 % vs. 4.9 %; p = 0.01).

CONCLUSIONS

Exposure to asbestos and sedentary jobs may be risk factors for Barrett's esophagus. Further studies are needed to confirm this finding.

Body mass index and risk of gastric cancer: a meta-analysis of a population with more than ten million from 24 prospective studies

BACKGROUND

To provide a quantitative assessment of the association between body mass index (BMI) and the risk of gastric cancer, we summarized the evidence from prospective studies.

METHODS

Eligible studies published up to November 30, 2012, were retrieved via computer searches of MEDLINE and EMBASE as well as manual review of references. Summary relative risks (SRR) with their corresponding 95% confidence intervals (CI) were calculated using a random-effects model.

RESULTS

A total of 24 prospective studies of BMI and gastric cancer risk with 41,791 cases were included in our analysis. Overall, both overweight (BMI, 25-30 kg/m(2)) and obesity (BMI, ≥30 kg/m(2)) were not associated with risk of total gastric cancer (overweight: SRR, 1.01; 95% CI, 0.96-1.07; obesity: SRR, 1.06; 95% CI, 0.99-1.12). Furthermore, we found increased BMI was positively associated with the risk of gastric cardia cancer (GCC; SRR = 1.21 for overweight and 1.82 for obesity), but not with gastric non-cardia cancer (GNCC; SRR = 0.93 for overweight and SRR = 1.00 for obesity). Similar results were observed in a linear dose-response analysis.

CONCLUSION

On the basis of meta-analysis of prospective studies, we find high BMI is positively associated with the risk of GCCs but not with GNCCs.

IMPACT

(i) On the basis of more definite and quantitative evidence than previously available, we found that increasing BMI was not a clear risk factor for total gastric cancer. (ii) Increased BMI was positively associated with risk of GCC but not with GNCCs.

Socio-demographic and geographical factors in esophageal and gastric cancer mortality in Sweden

Background

Socio-demographic factors and area of residence might influence the development of esophageal and gastric cancer. Large-scale population-based research can determine the role of such factors.

Methods

This population-based cohort study included all Swedish residents aged 30–84 years in 1990–2007. Educational level, marital status, place of birth, and place of residence were evaluated with regard to mortality from esophageal or gastric cancer. Cox regression yielded hazard ratios (HR) with 95% confidence intervals (CI), adjusted for potential confounding.

Results

Among 84 920 565 person-years, 5125 and 12 230 deaths occurred from esophageal cancer and gastric cancer, respectively. Higher educational level decreased the HR of esophageal cancer (HR = 0.61, 95%CI 0.42–0.90 in women, HR = 0.71, 95%CI 0.60–0.84 in men) and gastric cancer (HR = 0.80, 95%CI 0.63–1.03 in women, HR = 0.73, 95%CI 0.64–0.83 in men). Being unmarried increased HR of esophageal cancer (HR = 1.64, 95%CI 1.35–1.99 in women, HR = 1.64, 95%CI 1.50–1.80 in men), but not of gastric cancer. Being born in low density populated areas increased HR of gastric cancer (HR = 1.23, 95%CI 1.10–1.38 in women, HR = 1.37, 95%CI 1.25–1.50 in men), while no strong association was found with esophageal cancer. Living in densely populated areas increased HR of esophageal cancer (HR = 1.31, 95%CI 1.14–1.50 in women, HR = 1.40, 95%CI 1.29–1.51 in men), but not of gastric cancer.

Conclusion

These socio-demographic inequalities in cancer mortality warrant efforts to investigate possible preventable mechanisms and to promote and support healthier lifestyles among deprived groups.

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.

Occupational risks of esophageal cancer in Taiwanese men

This study aims to explore whether certain occupations were associated with the risk of esophageal squamous cell carcinoma (ESCC) in Taiwan. In a hospital-based case-control study, we collected 326 newly diagnosed ESCC patients and 386 age-matched controls (the ratio of case patients: controls = 1:1-2). All respondents completed a questionnaire, including 33 occupations in which environments potential exposure to cancer-related hazards are present. Workers with dust and metal exposure were categorized into Groups A and B, respectively. Relative risks for ESCC were estimated by odds ratios adjusting for covariates (AOR). Compared with the controls, farmer/gardener (AOR = 2.08, 95% CI = 1.02-4.24) and workers in Group A (AOR = 2.80, 95% CI = 1.21-6.47) had significantly higher risk for developing ESCC. A tendency of increased risk was also found in workers in group B (OR = 5.72 95% CI = 2.33-14.03), but such association was not significant after adjusting for other covariates (AOR = 1.57, 95% CI = 0.54-6.61). Our results suggested that farmer/gardener and workers with exposure to dust had a significant excess risk of ESCC. This study added further evidence to the current knowledge that occupational hazards are important in the development of ESCC.

Motor vehicle exposure and risk of oesophageal adenocarcinoma

OBJECTIVE

The introduction of motor vehicles in industrialised countries during the mid 20th century seems to fit with the increasing incidence and the strong male predominance of oesophageal adenocarcinoma. The aim of the study was to test this new hypothesis in a large case-control study.

METHODS

A nationwide, Swedish, population-based case-control study included 189 and 262 cases of oesophageal and cardia adenocarcinoma, respectively, 167 cases of oesophageal squamous-cell carcinoma and 820 frequency-matched controls during 1995-1997. Tumours were uniformly classified. Exposure data were collected at face-to-face interviews. Odds ratios (ORs), with 95% confidence intervals (CIs), were estimated and adjusted for confounding in multivariable logistic regression models.

RESULTS

There were no associations between regular contact with cars or airplanes regarding duration, frequency and age of contact and risk of oesophageal adenocarcinoma. The adjusted ORs for oesophageal adenocarcinoma, cardia adenocarcinoma and oesophageal squamous-cell carcinoma among persons spending at least two hours per day in cars were 1.3 (95%CI 0.7-2.3), 1.2 (95%CI 0.7-1.8), and 0.7 (95%CI 0.4-1.3), respectively. The corresponding ORs among frequent airplane passengers were 0.8 (95%CI 0.2-2.3), 1.1 (95%CI 0.5-2.2), and 0.9 (95%CI 0.3-2.5), respectively.

CONCLUSION

This large, population based case-control study does not support the hypothesis that frequent contact with motor vehicles has contributed to the increasing incidence or the male predominance of oesophageal adenocarcinoma.

Associations of risk factors obesity and occupational airborne exposures with CDKN2A/p16 aberrant DNA methylation in esophageal cancer patients

It is known that obesity and occupational airborne exposure such as dust are among risk factors of esophageal cancer development, in particular squamous cell carcinoma (SCC) of esophagus. Here, we tested whether these factors could also affect aberrant DNA methylation. DNAs from 44 fresh tumor tissues and 19 non-tumor adjacent normal tissues, obtained from 44 patients affected by SCC of esophagus (SCCE), were studied for methylation at the CDKN2A/p16 gene promoter by methylation-specific polymerase chain reaction assay. Statistical methods were used to assess association of promoter methylation with biopathological, clinical, and personal information data, including obesity and airborne exposures. Methylation at the CDKN2A/p16 gene promoter was detected in 12 out of 44 tumor samples. None of the non-tumor tissues exhibited the aberrant methylation. Our results confirmed previously described significant association with low tumor stage (P= 0.002); in addition, we found that obesity (P= 0.001) and occupational exposure (P= 0.008) were both significantly associated with CDKN2A/p16 promoter methylation. This study provides evidence that obesity and occupational exposure increase the risk of developing esophageal cancer through an enhancement of CDKN2A/p16 promoter methylation.

The risk of oesophageal cancer is not affected by a diagnosis of breast cancer

Oesophageal adenocarcinoma (OAC) is less common and develops at a later age in women compared with men. Endogenous oestrogen may therefore protect against OAC development. A cohort of women with breast cancer, a tumour commonly treated with oestrogen antagonists, was examined to identify the subsequent risk of developing OAC. Earlier studies have implicated radiotherapy in increasing oesophageal cancer (OC) risk among women with breast cancer. West Midlands Cancer Intelligence Unit data recording cancer diagnosis and treatment information was examined to identify patients with a first malignant primary breast cancer during 1977-2004. Patients were followed until diagnosis of a second primary cancer, death or end of the time period examined. Age-adjusted and period-adjusted standardized incidence ratios (SIR) were calculated as an estimate of relative risk for a second primary OC. Seventy-three thousand six hundred and thirteen women were eligible for the study, providing 486 679 person years at risk for analysis. One hundred and thirty-two second primary OCs were observed, compared with 121 expected (SIR 1.09; 95% confidence interval: 0.91-1.29). Radiotherapy treatment in 37 888 women did not affect the risk of a second primary OC (SIR 1.07; 95% confidence interval: 0.79-1.41). No difference was identified when examined by OC morphology.There was no association between breast cancer and a second primary OC. Radiotherapy that avoids deep irradiation in the treatment of breast cancer, local nodes or recurrence was not associated with an increased risk of developing a second primary OC.

Increased risk of oesophageal adenocarcinoma among upstream petroleum workers

OBJECTIVES

To investigate cancer risk, particularly oesophageal cancer, among male upstream petroleum workers offshore potentially exposed to various carcinogenic agents.

METHODS

Using the Norwegian Registry of Employers and Employees, 24 765 male offshore workers registered from 1981 to 2003 was compared with 283 002 male referents from the general working population matched by age and community of residence. The historical cohort was linked to the Cancer Registry of Norway and the Norwegian Cause of Death Registry.

RESULTS

Male offshore workers had excess risk of oesophageal cancer (RR 2.6, 95% CI 1.4 to 4.8) compared with the reference population. Only the adenocarcinoma type had a significantly increased risk (RR 2.7, 95% CI 1.0 to 7.0), mainly because of an increased risk among upstream operators (RR 4.3, 95% CI 1.3 to 14.5). Upstream operators did not have significant excess of respiratory system or colon cancer or mortality from any other lifestyle-related diseases investigated.

CONCLUSION

We found a fourfold excess risk of oesophageal adenocarcinoma among male workers assumed to have had the most extensive contact with crude oil. Due to the small number of cases, and a lack of detailed data on occupational exposure and lifestyle factors associated with oesophageal adenocarcinoma, the results must be interpreted with caution. Nevertheless, given the low risk of lifestyle-related cancers and causes of death in this working group, the results add to the observations in other low-powered studies on oesophageal cancer, further suggesting that factors related to the petroleum stream or carcinogenic agents used in the production process might be associated with risk of oesophageal adenocarcinoma.

The influence of deprivation and ethnicity on the incidence of esophageal cancer in England

The incidence of esophageal cancer (EC), particularly esophageal adenocarcinoma (EAC), has been rising dramatically. In the USA, esophageal squamous cell carcinoma (ESCC) is associated with deprivation and black ethnicity, while EAC is more common among whites. The influence of social deprivation and ethnicity has not been studied in England. West Midlands Cancer Intelligence Unit data were used to study the incidence of ESCC and EAC, and the influence of age, sex, socioeconomic status (Townsend quintiles by postcode) and ethnicity (to individual patients from Hospital Episode Statistics). From 1977 to 2004, a total of 15,138 EC were identified. Five-year directly age standardized incidence rates per 100,000 (95% CI) for men increased from 8.6 (8.0-9.1) in 1977-1981 to 13.7 (13.1-14.3) in 2000-2004 and for women from 5.0 (4.7-5.4) to 6.3 (5.9-6.6). ESCC incidence did not alter, but EAC incidence rose rapidly in males [2.1 (1.9-2.4) to 8.5 (8.1-9.0)] and in females [0.5 (0.4-0.6) to 1.7 (1.5-1.9)]. ESCC was strongly associated with the most socially deprived quintile. EAC was not associated with differences in socioeconomic status. EAC was significantly more common in white men 7.3 (6.9-7.7) and women 1.5 (1.3-1.6) when compared with black and Asian populations. In England the incidence of EAC has rapidly risen, particularly in men over the last three decades. ESCC was strongly associated with social deprivation. EAC was more common in white populations, but no association with the socioeconomic status was found.

Patients with prostate cancer are less likely to develop oesophageal adenocarcinoma: could androgens have a role in the aetiology of oesophageal adenocarcinoma?

Oesophageal adenocarcinoma (OAC) is more common in men. Androgens may therefore contribute to the pathogenesis of OAC. Prostate cancer (PC), an androgen sensitive tumor with a long natural history, may allow insights into this putative association. West Midlands Cancer Intelligence Unit data from 1977 to 2004 were examined to identify patients with a first malignant primary of PC. Patients were followed until diagnosis of a second primary cancer, death or end of the time period. Age- and period-adjusted standardized incidence ratios (SIR) were calculated as an estimate of the relative risk of a second malignant primary of the oesophagus. Between 1977 and 2004, 44,819 men within the West Midlands developed PC as a first primary malignancy. After exclusion for lack of follow-up, 38,627 men were eligible, providing 143,526 person years at risk for analysis. 86 second primary oesophageal cancers were observed, compared with 110 expected, resulting in an SIR of 0.78 (95% CI 0.62-0.96). There was a reduced risk of OAC 0.7 (0.5-0.95) but not of oesophageal squamous cell carcinoma (OSCC) 1.03 (0.69-1.47). The risk of developing OAC, but not OSCC, is lower than expected in patients with PC. A diagnosis of PC may be associated with aetiological factors that are negatively associated with OAC, or anti-androgen therapy may influence the development of OAC.

Overweight, obesity and gastric cancer risk: results from a meta-analysis of cohort studies

The relationship between excess body weight and gastric cancer risk has not been well studied to date. We therefore carried out a systematic review and meta-analysis of published cohort studies to evaluate the association between excess body weight and gastric cancer risk. An electronic search of the MEDLINE, PubMed, EMBASE and Academic Search Premier (EBSCO) databases, which contain articles published from 1950 onwards, was conducted in order to select studies for this meta-analysis. Ten studies with a total number of 9492 gastric cancer cases and a studied population of 3,097,794 were identified. Overall, excess body weight [body mass index (BMI)25] was associated with an increased risk of gastric cancer [odds ratio (OR)=1.22; 95% confidence intervals (CIs)=1.06-1.41]. Specifically, a stratified analysis showed that excess body weight was associated with an increased risk of cardia gastric cancer [overweight and obese (BMI 25), OR=1.55, 95% CIs=1.31-1.84] and gastric cancer among non-Asians (overweight and obese, OR=1.24, 95% CIs=1.14-1.36); however, the stratified analysis also showed that there was no statistically significant link between excess body weight and gastric cancer in the following subgroups: males (overweight and obese, OR=1.22, 95% CIs=0.96-1.55), females (overweight and obese, OR=1.13, 95% CIs=0.65-1.94), non-cardia gastric cancer (overweight and obese, OR=1.18, 95% CIs=0.96-1.45) and Asians (overweight and obese, OR=1.17, 95% CIs=0.88-1.56). The combined results of this meta-analysis, however, do indicate that overweight and obesity are associated with an increased risk of gastric cancer. The strength of the association also increases with increasing BMI.

Environmental causes of esophageal cancer

This article reviews the environmental risk factors and predisposing conditions for the two main histologic types of esophageal cancer. Tobacco smoking, excessive alcohol consumption, drinking maté, low intake of fresh fruits and vegetables, achalasia, and low socioeconomic status increase the risk of esophageal squamous cell carcinoma. Results of investigations on other potential risk factors, including opium consumption, intake of hot drinks, eating pickled vegetables, poor oral health, and exposure to human papillomavirus, polycyclic aromatic hydrocarbons, N-nitroso compounds, acetaldehyde, and fumonisins are discussed. Gastroesophageal reflux, obesity, tobacco smoking, hiatal hernia, achalasia, and, probably, absence of H pylori in the stomach increase the risk of esophageal adenocarcinoma. Results of studies investigating other factors are also discussed.

Personal exposure to inhalable cement dust among construction workers

Objective- A case study was carried out to assess cement dust exposure and its determinants among construction workers and for comparison among workers in cement and concrete production.Methods- Full-shift personal exposure measurements were performed and samples were analysed for inhalable dust and its cement content. Exposure variability was modelled with linear mixed models.Results- Inhalable dust concentrations at the construction site ranged from 0.05 to 34 mg/m(3), with a mean of 1.0 mg/m(3). Average concentration for inhalable cement dust was 0.3 mg/m(3) (GM; range 0.02-17 mg/m(3)). Levels in the ready-mix and pre-cast concrete plants were on average 0.5 mg/m(3) (GM) for inhalable dust and 0.2 mg/m(3) (GM) for inhalable cement dust. Highest concentrations were measured in cement production, particularly during cleaning tasks (inhalable dust GM = 55 mg/m(3); inhalable cement dust GM = 33 mg/m(3)) at which point the workers wore personal protective equipment. Elemental measurements showed highest but very variable cement percentages in the cement plant and very low percentages during reinforcement work and pouring. Most likely other sources were contributing to dust concentrations, particularly at the construction site. Within job groups, temporal variability in exposure concentrations generally outweighed differences in average concentrations between workers. 'Using a broom', 'outdoor wind speed' and 'presence of rain' were overall the most influential factors affecting inhalable (cement) dust exposure.Conclusion- Job type appeared to be the main predictor of exposure to inhalable (cement) dust at the construction site. Inhalable dust concentrations in cement production plants, especially during cleaning tasks, are usually considerably higher than at the construction site.

Smoking and gastric cancer: systematic review and meta-analysis of cohort studies

OBJECTIVE

We conducted a systematic review of studies addressing the relation between cigarette smoking and gastric cancer to estimate the magnitude of the association for different levels of exposure and cancer locations.

METHODS

Published cohort, case-cohort, and nested case-control studies were identified through PubMed, Scopus, and Web of Science searches, from inception to July 2007. Relative risk (RR) estimates referring to the comparison of two categories of exposure (e.g., current smokers vs. never smokers) were combined using a random effects model. Generalized least squares regression was used for trend estimation. Heterogeneity was quantified using the I (2) statistic.

RESULTS

Forty-two articles were considered for the systematic review. Comparing current smokers with never smokers: the summary RR estimates were 1.62 in males (95% CI: 1.50-1.75; I (2) = 46.0%; 18 studies) and 1.20 in females (95% CI: 1.01-1.43; I (2) = 49.8%; nine studies); the RR increased from 1.3 for the lowest consumptions to 1.7 for the smoking of approximately 30 cigarettes per day in the trend estimation analysis; smoking was significantly associated with both cardia (RR = 1.87; 95% CI: 1.31-2.67; I (2) = 73.2%; nine studies) and non-cardia (RR = 1.60; 95% CI: 1.41-1.80; I (2) = 18.9%; nine studies) cancers.

CONCLUSION

Our study provides solid evidence to classify smoking as the most important behavioral risk factor for gastric cancer.

Airborne exposures and risk of gastric cancer: A prospective cohort study

There is an unexplained male predominance among patients with gastric cancer, and many carcinogens are found in male-dominated dusty occupations. However, the relation between occupational exposures and risk of gastric cancer remains unclear. To investigate whether airborne occupational exposures might influence the risk of noncardia gastric cancer, we used a large, prospective cohort study of male Swedish construction workers. These workers were, during the period 1971-1993, regularly invited to health examinations by a nationwide occupational health service organization. Data on job titles and other variables were collected through self-administered questionnaires and forms completed by the health organization's staff. Industrial hygienists assessed 12 specific airborne occupational exposures for 200 job titles. Gastric cancer, death or emigration occurring during follow-up in 1971-2002 were identified by linkage to the Swedish registers of Cancer, Causes of Death and Total Population, respectively. Incidence rate ratios (IRR) and 95% confidence intervals (CI), adjusted for attained age, tobacco smoking, calendar period and body mass, were derived from Cox regression. Among 256,357 cohort members, contributing 5,378,012 person-years at risk, 948 noncardia gastric cancers were identified. Increased risk of this tumor was found among workers exposed to cement dust (IRR 1.5 [95% CI 1.1-2.1]), quartz dust (IRR 1.3 [95% CI 1.0-1.7]) and diesel exhaust (IRR 1.4 [95% CI 1.1-1.9]). Dose-response relations were observed for these exposures. No consistent positive associations were found regarding exposure to asbestos, asphalt fumes, concrete dust, epoxy resins, isocyanates, metal fumes, mineral fibers, organic solvents or wood dust. In conclusion, this study provides some support to the hypothesis that specific airborne exposures increase the risk of noncardia gastric cancer.

Time trends in socioeconomic differences in incidence rates of cancers of gastro-intestinal tract in Finland

BACKGROUND

The magnitude of socioeconomic differences in health varies between societies, and over time within a given society. We studied the association between social class and incidence of cancers of the gastro-intestinal tract over time in a large cohort in Finland.

METHODS

We studied social class variation among 45-69 year-old Finns during 1971-95 in incidence of cancers of the gastro-intestinal tract by means of a computerized record linkage of the Finnish Cancer Registry and the 1970 Population Census, which included social class data.

RESULTS

There were 2.3 million individuals in the cohort under follow-up, with 1622 cases of cancer of the esophagus, 8069 stomach (non-cardia), 1116 cardia, 408 small intestine, 6361 colon, 5274 rectum, 1616 liver, 1756 gallbladder, and 5084 pancreas during 1971-1995. Cancers of the esophagus, stomach, cardia, gallbladder and pancreas were most common among persons belonging to a low social class. Cancers of the small intestine in males only, colon in both genders, and rectum in females were most common in the higher social classes. Incidence of stomach cancer decreased and incidence of colon cancer increased over time in both genders in all social classes, and the large differences between social classes remained unchanged over time. Incidence rates of cardia cancer did not change substantially over time.

CONCLUSION

There is a large variation in incidence of cancer of the gastrointestinal tract by social class in Finland. Although much of the observed social class differences probably could be explained by known etiological factors such as diet, physical exercise, alcohol consumption, smoking and exogenous hormone use, part of the variation is apparently attributable to largely unknown factors.

Integrating Studies on Carcinogenic Risk of Carbon Black: Epidemiology, Animal Exposures, and Mechanism of Action

OBJECTIVE

We sought to address the toxicology literature on carbon black (CB) since 1996, when IARC reclassified CB from group 3 to group 2B.

METHODS

We reviewed epidemiology and laboratory studies from 1996 to 2006, focusing on new analyses of worker populations, on species differences in tumorigenicity of poorly soluble particles, and on the role of particle-bound organics in tumorigenicity.

RESULTS

Some epidemiology studies have reported positive associations between cancer risk and worker's possible exposure to CB, but larger studies, in more highly exposed populations, have not shown consistent patterns of either elevated risk or dose-response. High levels of inhaled CB were linked with rat lung tumors in 1996, but today scientists increasingly recognize that rats exhibit a unique lung tumor response to all inert inhaled particles that is unlikely to be relevant to humans. On mechanism of action, new reports have continued to show that CB has a high surface area of elemental carbon, and a low quantity of organic material, which is poorly bioavailable.

CONCLUSION

Overall, the new epidemiological evidence decreases concerns for cancer risk compared with pre-1996 evidence. Laboratory studies support a conclusion that the mechanism of tumorigenicity of CB in rats is no different from that of any poorly soluble particle, ie, toxicity results from the particle overload per se, and not from the particles' chemistry. Thus, research published after 1996 has not identified an increase in support for CB cancer risk, but rather, points to limited and inadequate evidence for carcinogenicity.

Carcinogens in the Construction Industry

The construction industry is a complex work environment. The work sites are temporary and rapidly changing. Asbestos has been widely used in construction industry, but the risks were primarily detected in specialized trades, such as insulation workers and plumbers. Today, the majority of cases related to asbestos exposure will occur in other occupational groups in the construction industry. In a large cohort of Swedish construction workers, insulators and plumbers constituted 37% of all cases of pleural mesothelioma between 1975 and 1984 while they constituted 21% of the cases between 1998 and 2002. It is estimated that 25-40% of all male cases of pleural mesothelioma in Sweden are caused by asbestos exposure in the construction trades. There are many other known carcinogens occurring in the construction industry, including PAHs, diesel exhausts, silica, asphalt fumes, solvents, etc., but it is difficult to estimate exposures and thus the size of the risk. The risk of cancer is less easy to detect with traditional epidemiological methods in the construction industry than in other industrial sectors. It is not sufficient to rely upon broad epidemiological data to estimate the risk of cancer due chemicals in the construction industry. Thus, a strategy to decrease exposure, e.g., to dust, seems a feasible way to reduce the risk.

Occupational risk factors for esophageal and stomach cancers among female textile workers in Shanghai, China

The authors evaluated associations between occupational exposures in the textile industry and the risks of esophageal cancer and stomach cancer. The authors conducted a case-cohort study nested in a cohort of female textile workers in Shanghai, China. One hundred and two workers with incident esophageal cancer and 646 workers with incident stomach cancer diagnosed between 1989 and 1998 were compared with an age-stratified reference subcohort (n = 3,188). Work histories were ascertained for all study subjects from factory personnel records or interviews. Exposures were reconstructed for chemicals and dusts by linking work history data with a job-exposure matrix developed for the Shanghai textile industry. Hazard ratios and 95 percent confidence intervals were calculated with Cox proportional hazards modeling adapted for the case-cohort design. Risk of esophageal cancer was associated with long-term (> or = 10 years) exposure to silica dust (hazard ratio = 15.8, 95% confidence interval: 3.5, 70.6) and metals (hazard ratio = 3.7, 95% confidence interval: 1.9, 7.1). Cumulative exposure to endotoxin, a contaminant of cotton dust, was inversely related to risks of both esophageal cancer (p-trend = 0.01) and stomach cancer (p-trend < 0.001) when exposures were lagged 20 years. Endotoxin has not been previously reported to be a protective factor for either stomach cancer or esophageal cancer and therefore warrants further study.

Gastric cancer: global pattern of the disease and an overview of environmental risk factors

This first part of this chapter looks at the worldwide burden of gastric cancer at the beginning of the 21st century and summarises available population-based routine data that describes the variation in incidence of the disease in relation to age, sex, geography and time period. Consideration is also given to the differences in the descriptive epidemiology of gastric cancer arising in the proximal cardia region of the stomach. In the second part of the chapter, a brief review of the main identified environmental risk factors is conducted drawing, where available, on published systematic literature overviews and meta-analyses. Evidence relating the aetiology of gastric cancer to Helicobacter pylori infection, dietary factors, smoking, occupation, physical activity and anthropometry is presented.