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W. Ahrens1, C. Mambetova2. 1Bremen Institute for Prevention Research and Social Medicine; 2Scientific Research Institute of Haematology and Blood Transfusion of the Ministry of Health of the Republic of Uzbekistan
ObjectivesThis study investigates the association between extrahepatic biliary tract (EBT) cancer and exposure to endocrine disrupting compounds (EDCs).
Methods183 men with histologically confirmed carcinoma of the EBT and 1938 matched controls were interviewed between 1995 and 1997 in the frame of an international multi‐centre case‐control study in six European countries (Denmark, France, Germany, Italy, Spain and Sweden). Self‐reported job descriptions were converted into primary quantification variables (intensity, probability and duration of the exposure) for 14 EDCs. Cases were compared with 1421 population controls and 517 colon adenocarcinoma patients. Odds ratios (OR) and 95% confidence intervals (CI) were obtained from unconditional logistic regression and adjusted for age, country and gallstones.
ResultsOccupational exposure to EDCs resulted in an OR of 1.4 (95% CI 0.9 to 2.1) with an inconsistent dose–effect relationship for cumulative exposure (low: OR 1.2, 95% CI 0.6 to 2.3; medium: OR 1.8, 95% CI 1.0 to 3.4; high: OR 1.5, 95% CI 0.9 to 2.7) (only index subjects). The adjusted OR for EBT cancer after exposure to PCBs was 2.3 (95% CI 1.1 to 4.8; only index subjects). None of the other agents considered revealed a similar association with EBT cancer.
ConclusionOur findings do not show a convincing association between exposure to EDCs in the workplace and the risk for EBT cancer in men. However, among the agents of interest PCBs could possibly be a strong risk factor.
Key wordscase‐control study; extrahepatic bile duct carcinoma; xenoestrogens
I. GusevaCanu1, E. DupreeEllis2, M. Tirmarche1. 1Institute of Radioprotection and Nuclear Safety; 2Oak Ridge Associated Universities
ObjectivesWorkers involved in the nuclear fuel cycle have a potential of internal exposure to uranium. The objective of this article is to conduct a critical review of epidemiological results currently available concerning the relationship between occupational internal exposure to uranium compounds and the risk of cancer.
MethodsEpidemiological studies on workers with a potential for internal exposure to uranium published since 1980 were searched using search engines with related keywords. This review was limited to workers of the nuclear fuel cycle excluding uranium miners.
ResultsEighteen cohorts and five nested case‐control studies are included in this review. Workers occupationally exposed to uranium appear to be at increased risk of mortality from neoplasm of the lung, larynx, and lymphatic and haematopoietic tissue. Statistically significant dose–response relationships between internal radiation dose from uranium exposure and mortality from lymphatic and haematopoietic malignancies and upper aerodigestive cancer are reported in only one study. The common weaknesses in most reviewed studies include low statistical power and inaccurate assessment of internal exposure to uranium.
ConclusionThe overall epidemiological results currently available provide limited evidence for an association between internal exposure to uranium and the risk of cancer. Further investigations should be focused on more precise assessment of occupational exposure and address the issue of potential confounders, the best approach being probably a large multi‐centric study with a common protocol and joint analyses.
Key wordsoccupational exposure; nuclear workers; cancer mortality
C. J. Jansson1, N. Plato2. 1Unit of Esophageal and Gastric Research, Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden; 2Division of Occupational Medicine, Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden
ObjectivesWe hypothesised that airborne particles might be deposited in the airway region and swallowed to act as carcinogens directly on the oesophageal or cardia mucosa. Lack of measurements of past exposure is a weakness when assessing exposure in retrospective epidemiological studies. In a Swedish case‐control study including 189 oesophageal adenocarcinoma patients, 262 cardia adenocarcinoma patients, 167 oesophageal squamous‐cell carcinoma patients and 820 control persons we tried to estimate historical exposure to particular agents with limited information. A method was developed to assess the best available estimations for each study participant.
MethodsThe study questionnaire contained information about lifetime occupational history, including questions about duration of employment, workplace and work tasks, and questions regarding regular contact with specific agents. Occupational particulate exposure for 10 airborne agents was blindly assessed for the 1438 participants using a semi‐quantitative method. A senior industrial hygienist estimated the exposure based on probability (three grade scale), frequency (five grade scale), intensity (three grade scale) and duration (exposed years). A combined additive and multiplicative model was used to calculate the cumulative particulate exposure for each participant.
ResultsMore than 5000 different occupational periods were assessed. The mean length of the occupation of longest duration among the study participants was 24 years. Among the controls 55% had ever been exposed to combined particular agents (eg, wood dust, metal dust, asbestos), while the corresponding percentages among the patients with oesophageal adenocarcinoma, cardia adenocarcinoma and oesophageal squamous‐cell carcinoma were 67%, 58% and 55%, respectively. No associations were found between airborne particle exposure and the different cancer types, except for tendencies of positive associations between high exposure to pesticide aerosols and risk of oesophageal (OR 2.3, 95% CI 0.9 to 5.7) and cardia adenocarcinoma (OR 2.1, 95% CI 1.0 to 4.6).
ConclusionThe expert assessment method is considered to be more valid and produce less misclassification than other methods, even though it is relatively costly. Specific airborne occupational exposures do not seem to be of major importance in the aetiology of oesophageal or cardia adenocarcinoma and are unlikely to contribute to the increasing incidence of these tumours.
Key wordsairborne; particles; exposure
A. C. Pesatori1, D. Consonni2, M. Bonzini2, R. Sindaco1, G. Dinoia1, T. Aquilina1, P. Grillo2, P. A. Bertazzi2. 1Department of Occupational Health, University of Milan, Italy; 2IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, Milan
ObjectivesThe 1976 Seveso accident caused the contamination of a large inhabited area by 2,3,7,8‐tetrachlorodibenzodioxin (TCDD). Three zones with decreasing soil TCDD levels were delimited: A (highest), B (high) and R (low and patchy). Persons ever living in the three contaminated zones and in a surrounding non‐contaminated area were followed up, blind of their exposure status, to evaluate long‐term health consequences through mortality and cancer incidence studies. The main finding of the mortality study (1976–2001) was an increase in lymphatic and haematopoietic cancers among both genders in the most polluted zones (A and B). We report here preliminary results of the cancer incidence study updated to 1996.
MethodsIncident cancer cases were ascertained through the hospital discharge registration system of the Lombardy region, where over 95% of the cohort was still resident in 1986. For each case all relevant medical records were reviewed (over 3000/year). Relative risks (RR) and 95% confidence intervals (CI) were estimated with Poisson regression techniques controlling for age, gender and calendar period using the surrounding non‐ contaminated area as reference. Data collection and revision is in progress and has been completed for 96% of the cohort.
ResultsA preliminary analysis has been conducted on subjects aged 0–74 years residing in the area at the time of the accident. Cases ascertained through death certificate only (11%) were included in the analysis. The percentage of histologically confirmed diagnosis was 76%. In zone A, all cancer incidence did not differ from expectation; a twofold increased risk for breast cancer was observed (seven cases, 95% CI 0.6 to 6.2) and four lymphohaemopoietic cancers yielded a RR of 1.4 (95% CI 0.3 to 5.4). In zone B, the risk for all cancers was 20% higher than expected (RR 1.2; 95% CI 1.0 to 1.4) and a twofold increased risk in lymphohaemopoietic cancers was observed (RR 1.9; 95% CI 1.2 to 3.0). Other increased risks refer to rectal and biliary tract cancers. Nine soft tissue sarcomas (RR 1.6; 95% CI 0.5 to 5.0) were observed in the least contaminated area (zone R).
ConclusionThe preliminary results of the cancer incidence study are consistent with the increased risk for lymphatic and haemopoietic cancers observed in the mortality follow‐up. Further analyses are in progress.
Key wordsTCDD; cancer; Seveso
B. Swiatkowska. Nofer Institute of Occupational and Environmental Medicine
ObjectivesLaryngeal cancer is the second most common respiratory cancer after lung cancer in the world. Approximately 160000 new cases occurred in 2002, 40% of which were in developed countries. The objective of this paper was to provide a brief overview of the occupational risk factors for laryngeal cancer risk.
MethodsData sources were Medline from January 1950 to December 2006, title in the field. Search terms included: laryngeal cancer, cancer of the larynx and occupational exposure. Book chapters, monographs, relevant news reports, and web material were also reviewed to find articles.
ResultsTobacco smoking and alcohol consumption are the major aetiological risk factors for cancer of the larynx. In this study, we evaluated the role of selected occupational exposures in the aetiology of laryngeal carcinoma. The results of the literature review suggest that workers exposed to sulfuric acid mist, nickel, mineral oil or wood dust have an increased risk of laryngeal cancer. Laryngeal cancer has been also reported in diesel exhaust. Other published reports showed increased risk of laryngeal carcinoma with polycyclic aromatic hydrocarbons and rubber products exposure. Some studies also reported a limited carcinogenic effect of formaldehyde and solvent exposure on laryngeal carcinogenicity.
ConclusionLaryngeal cancer generation is conditioned by many synergic factors. Effective prevention programs, especially against causal risk factors, must be developed to minimise potential health risks and prevent future health costs.
Key wordslaryngeal cancer; occupation; risk factors
M. T. Wu. Graduate Institute of Occupational Health, Kaohsiung Medical University
ObjectivesMany carcinogens, including polycyclic aromatic carbons, aromatic amines and nitro‐polycyclic aromatic hydrocarbons, identified from cooking oil fumes and similar to the content of cigarette smoke, appear in kitchens of Chinese homes where women prepare food daily. Thus in this study, we investigate the effect of environmental exposure to cooking oil fumes on the risk of cervical neoplasm (CIN).
MethodsThis is a community‐based case‐control study. Potential study subjects were selected through Pap smear screening in Kaohsiung County, Taiwan. A total of 73 high‐grade squamous intraepithelial neoplasms (HGIL), 153 low‐grade squamous intraepithelial neoplasms (LSIL), and 526 normal subjects were successfully recruited between January 2003 and December 2006.
ResultsAmong the subjects, 57 (78.1%), 108 (70.6%) and 466 (88.6%) of 73 HSIL, 153 LSIL and 526 normal subjects, respectively, cooked at home in a kitchen at least once a week during the ages of 20–40, respectively. Of them, six (10.5%), five (4.6%) and 18 (3.9%) out of 57 HSIL, 108 LSIL and 466 normal subjects, respectively, did not install a fume extractor in their home in that age period. We found that those who cooked without the presence of a fume extractor between the ages of 20 and 40 to have a 2.93 times higher risk (95% CI 1.11 to 7.71; p=0.02) of developing CIN (or HSIL) than those who cooked with the presence of a fume extractor during the same age period.
ConclusionTheses preliminary data suggest that the installation of a fume extractor can protect against the development of CIN when Taiwanese women regularly cook in the home kitchen.
FundingSupported by Taiwan NHRI‐EX95‐9205PI.
Key wordscervical neoplasm; cooking oil fumes; fume extractor
P. C. Chu1, J. D. Wang1, J. S. Hwang2. 1Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University; 2Institute of Statistical Science, Academia Sinica
ObjectivesThe estimation of life expectancy and expected years of life loss (EYLL) for cancer patients is valuable for policy planning and prevention. Parametric models may not be suitable for data with high censoring rates. The aim of this study was to use a novel semi‐parametric projection method to estimate life expectancy and expected years of life loss (EYLL) through major cancers.
MethodsThe national cancer registry databases were obtained, with this information then being linked to a national death registry database to construct the survival function. The 425294 patients were enrolled with diagnoses of 17 major cancers, all registered with cancer registry databases between 1990 and 2001, with their survival being followed up until the end of 2004. The Monte Carlo simulation method was used to extrapolate survival for up to 50 years to derive the life expectancy for different types of cancer. The EYLL is the difference between the mean survival of cancer cohorts and the mean life expectancy for age‐ and gender‐matched reference populations.
ResultsLeukaemia had the largest EYLL (19.3 years) and skin cancer had the smallest (1.6 years). Liver cancer had the largest total‐person EYLL. In addition, cancers of the oral cavity and breast were noticed because of age at diagnosis and number of incidence cases. Validity tests indicated that under high censoring rates, the relative biases of the semi‐parametric extrapolated estimates are usually below 5%, which seemed better than a parametric method, namely the Weibull model.
ConclusionDifferent types of occupational cancer produce varied burdens on public health and may deserve distinct resources for prevention or screening. The method herein could be a feasible one to project life expectancy and EYLL for occupational cancer with premature mortality beyond the follow‐up limit.
Key wordslife expectancy; expected years of life lost; Monte Carlo method
D. Boers1, L. Portengen1, H. B. Bueno‐de‐Mesquita2, D. Heederik1, R. Vermeulen1. 1IRAS; 2RIVM
ObjectivesIn the early 1980s, a retrospective cohort study was conducted in two factories (referred to as A and B) producing several chlorophenoxy herbicides. The initial study revealed an increased risk of total mortality for exposed workers which was subsequently confirmed in a follow‐up study conducted in 1991 for factory A only (RR 1.8). In addition, increased risks were found for cancer and ischaemic heart disease mortality. The purpose of the current, third follow‐up is to provide an updated assessment of total mortality and cause‐specific mortality for both factories.
MethodsThe study population was defined as all persons working in one of the factories during 1955–1985 at factory A, or during 1965–1986 at factory B. The third follow‐up included an additional 15–16 years of follow‐up until December 2006. Information on vital status was obtained from municipal records. Cause‐specific mortality will be updated by linkage to death certificates at Statistics Netherlands. Analyses were done using Cox proportional hazard models, using attained age as the time‐scale, and including exposure as a time‐varying covariate.
ResultsFollow‐up of the third cohort was virtually complete with only 6% lost to follow‐up. At the end of the third follow‐up the study included over 72000 person‐years. A total of 603 persons had died, 382 in factory A and 221 in factory B. The mortality rate among males aged 65–70 in the study was 23.6/1000 person‐years, which is comparable to that of 27/1000 person‐years in the general population. Preliminary analysis showed that exposed workers in factory A had a significant increased risk of all‐cause mortality (hazard ratio (HR) 1.3; p=0.01) compared to non‐exposed workers. In factory B no such association was observed (HR 1.0; p=0.90).
ConclusionThe increased risk of all‐cause mortality in factory A is consistent with earlier reports, although the estimated relative risk is somewhat lower during this follow‐up. Differences between factory A and B may be due to differences in exposure especially given that factory A was involved in a serious industrial accident in 1963. Further analyses using serum levels of PCDDs, PCDFs, PCBs and polychlorinated biphenyls should confirm this. Analyses on cause‐specific mortality are ongoing.
Key wordsphenoxy herbicides; mortality; dioxins