Real-world efficacy of bezlotoxumab for prevention of recurrent Clostridium difficile infection: a retrospective study of 46 patients in five university hospitals in Finland

Reports on real-world experience on efficacy of bezlotoxumab (BEZ) has been lacking thus far. We retrospectively studied the efficacy and safety of BEZ in preventing the recurrence of Clostridium difficile infection (CDI) in five university hospitals in Finland. Seventy-three percent of our 46 patients remained free of recurrence in the following 3 months and the performance remained as 71% effective also among immunocompromised patients. In severe CDI, BEZ prevented recurrence in 63% of cases. From our study patients, 78% had three or more known risk factors for recurrence of CDI. Eight of our patients were waiting for fecal microbiota transplantation but after stopping the antibiotics that were continued to prevent recurrence of CDI and after receiving BEZ, all remained free of recurrence and did not need the procedure. Success with BEZ as an adjunctive treatment in preventing recurrence of CDI in high-risk patients may be rated as high. Among a subgroup of our patients, those already evaluated to be in need of fecal microbiota transplantation, BEZ seems to be an alternative option.

Global Corporate Policy for Financing Health Services in the Third World: The Structural Adjustment Crisis

Western nations and international financiers are usually the donors for most of the Third World countries. International funds allocated for development projects in these nations are under control of such groups, in which global corporate policy, bureaucracy, and neo-liberalization play a major role. International financiers also bias the socio-political, environmental, local administration, and even public health policy of the poor nations. Financial packages are usually sanctioned, distributed, and reimbursed under strict terms and conditions that Third World nations must heed and agree to with the fundamental commitment to change accordingly. Obviously, these terms and conditions are complicated for local governmental authorities. In most of the implementation phase of a project supported by foreign loan/aid, the efficient features of their own or the donors may be reflected, while the proposal and prospects for the actual benefits are left to the local populace. Cutting government spending and neglecting the benefits to poor people, global capitalism maintains corporate policy that may also focus on the goals of profit making instead of public benefit. As such, enhancing privatization, structural adjustments have been devised by the international financiers in many sectors. The reason is that private sectors must necessarily comply with the market dynamics of free choice and with the belief that it could be more efficient and equitable than the local government's action. It is thus important that healthcare professionals, government officials, and others solicit their opinions about international policy on privatization programs through a range of cost-benefit analyses. In order to identify and evaluate the negative effects of structural adjustment, this article comments on international policy for financing health services in the Third World.

An Icon-based Interview for the Assessment of Occupational Pesticide Exposure in a Case–Control Study of Childhood Leukemia

An icon-calendar interview form (ICF) for a case-control study of childhood leukemias and parental exposures to pesticides is described. It includes calendar sheets, icons for life events, crops, jobs, regions, non-agricultural jobs, application techniques and personal protection, markers for durations of exposure patterns, and checklists of pesticides. The ICF collects monthly data from two years before birth until diagnosis of cancer (index children) or until either the interview date or age 15 (controls). Data ascertainment was easy in 62% of interviews, moderately easy in 32%, and difficult in 6%. Seventy-eight subjects delivered data on specific pesticides with pesticide checklists, which improved identification of pesticides. ICF performs satisfactorily for crops, tasks, and other determinants of exposure. Data on pesticides will be further improved by introducing external data use on different crops, time periods, and regions, and by exposure modeling for 27 pesticides.

Registration of fatal occupational injuries in Costa Rica, 2005-2006

Data on fatal occupational injuries (FOIs) for Latin America are controversial. Costa Rican national rates are inconsistent with estimates extrapolated from other countries. We reviewed the files for all possible FOIs in Costa Rica for 2005-2006 at the National Insurance Institute and at the Center of Forensic Sciences by formality/informality of work, sex, age, economic activity, occupation, and cause of death. The national mortality rate was estimated at 9.5/100,000 person-years (342 deaths). The informal/formal rate ratio was 1.06. Men's rates were over 10 times higher than women's and increased with age. The highest rates were found for transport, storage, and communication (32.1/100,000 person-years), and, by occupation, for messengers and delivery men (91.4). Leading causes of death were traffic injuries and gunshots. Recalculated rates are probably underestimates. Data limitations include the absence of systematic identification and registration among informal sector workers and other groups such as children and farm workers.

Social determinants of workers' health in Central America

This communication summarizes the available data on work-related determinants of health in Central America. The Central American working population is young and moving from agriculture toward industry and services. Ethnicity, gender, migration, subemployment and precarious work, informality, rural conditions, low-level educational, poverty, ubiquitous worksite health hazards, insufficient occupational health services, low labor inspection density, and weak unions define the constellation of social determinants of workers' health in Central America. Data are, however, scanty both for hazards and work-related illnesses and injuries. Governments and industries have the responsibility of opening decent work opportunities, especially for those facing multiple inequalities in social determinants of health. A first step would be the ratification and implementation of the ILO Convention (187) on occupational safety and health by the seven national governments of the region.

Fatal occupational injuries in Nicaragua, 2005

We attempt to estimate the rate of fatal occupational injuries (FOI) in Nicaragua for 2005, using 10 incomplete data sources. Based on the 173 identified FOIs, the crude empirical FOI rate estimate was 8.3 per 100,000 employed (12.3 men; 1.8 women) and highest in the 25-29 age group (15). The overall rate, corrected by capture-recapture modeling, was 11.6. Manufacturing represented a high rate (11.7); the formal economy rate (12.3) was higher than the informal economy (6); mining (110.3) and electricity (76.2) had the highest industry rates; and the most common agents of FOIs were motor vehicles. With 10 major sources, the extent of FOIs remains grossly underestimated and biased across worker strata. The FOIs among informal and agricultural workers tend to remain invisible, as there is no systematic surveillance by any agency. Changes in legislation and implementation are necessary to correct the situation.

SALTRA: a regional program for workers' health and sustainable development in Central America

In 2003, the university-based Program on Work and Health in Central America, SALTRA, was launched to build national and regional capacities in occupational safety and health with the goal of preventing and reducing poverty in Central America. SALTRA has implemented 20 projects including action projects in priority sectors (e.g., construction, sugarcane, hospitals, migrant coffee workers); strengthening of surveillance (occupational health profiles, carcinogenic exposures, fatal injuries and pesticides); a participatory model for training and risk monitoring by workers; building occupational health capacity for professionals, employers, and workers, with collaborating networks between the countries; strengthening of universities in work, environment, and health; studies of serious occupational and environmental situations; communication channels; and continued efforts to raise political awareness. SALTRA has placed issues of workers' health on political, business, and academic agendas throughout the region and has laid the foundations for achieving substantial future improvements in health conditions of all workers in the region. External evaluators envisioned SALTRA as an innovative development model.

Causas y prevención del cáncer ocupacional

Las neoplasias ocupacionales son altamente prevenibles. Esta comunicación resume los datos de los riesgos cancerígenos ocupacionales, destacando grupos importantes de trabajadores y la prevención. La Agencia Internacional para la Investigación del Cáncer (IARC) ha identificado en el Grupo 1 (causa cáncer en humanos), 29 agentes que pueden presentarse en el lugar de trabajo, 26 en el Grupo 2 A (probablemente cancerígeno) y 113 en el Grupo 2B (posiblemente cancerígeno). Los agentes frecuentes en Centroamérica incluyen la radiación solar (Grupo 1) y la radiación ultravioleta (2A), las emisiones diesel (2A), los hidrocarburos poliaromáticos (1 - 3), el humo de tabaco ambiental (1), los compuestos de cromo hexavalente (1) y el benceno (1). En cuanto a los cánceres de mujeres, estudios de cáncer de mama y ovarios sugieren asociaciones con agentes ocupacionales. Los datos en la economía informal son pocos. Peligros cancerígenos para agricultores y peones agrícolas contemplan la exposición a radiación ultravioleta solar, virus, zoonosis, polvos, aflatoxinas, emisiones de diesel, solventes y plaguicidas. Agentes cancerígenos potenciales presentes en el Sector Salud incluyen: óxido de etileno, formaldehído, humo de tabaco ambiental, tricloroetileno, tetracloroetileno, benceno, asbesto, drogas, hormonas, antibióticos, plaguicidas, virus y desechos y gases cancerígenos. Algunas exposiciones durante el desarrollo y la infancia someten a los niños a riesgos cancerígenos. Prevenir los riesgos para la salud en el lugar de trabajo es responsabilidad del empleador. Se debe actuar con precaución en respuesta a la limitada evidencia plausible y creíble, sobre un peligro probable, y establecer comisiones mixtas de salud y seguridad en lugares de trabajo.

Insecticide residues on hands: assessment and modeling with video observations of determinants of exposure--a study among subsistence farmers in nicaragua

This investigation quantitatively assessed hand residues of chlorpyrifos and methamidophos in a field setting and sought to explain the residues through application volume and determinants of exposure using application data for 28 subsistence farmers in the Pacific Region of Nicaragua. Hand residues were estimated by recovery of the pesticides by standardized wipe sampling for both hands, analyzed with solvent extraction and gas chromatography with electron capture detector. Application volumes were based on data on individual spraying rates and mixing volumes. Eleven determinants of exposure, related to work practices during mixing and spraying of the pesticides, were assessed for each subject from videotapes. Correlation and regression analyses estimated the associations between hand residues, application volume, pesticide type, and determinants of exposure. Correlations between residues for different hand parts were high (r 0.75-0.98). Total hand residue (sum of residues of parts of both hands) correlated with application volume (r 0.43, p 0.02), not washing hands (r 0.41, p 0.04), spraying nozzle forward (r 0.26, p 0.17), manipulation of hose (r 0.32, p .09), and insecticide type (chlorpyrifos vs. methamidophos; r 0.31, p 0.10). A model that explained total hand residue with these five variables yielded a multiple correlation coefficient of 0.67 (p 0.01). Unmeasured determinants and/or narrow range of the exposure situation probably account for the unexplained variance of the residues.

Determinants of health in seasonal migrants: coffee harvesters in Los Santos, Costa Rica

In the agroexport zone of Los Santos Zone in Costa Rica, coffee is harvested by migrant labor. Most migrants are from Panama and Nicaragua. We describe migrants' housing- and service-related health determinants, with analyses of ethnicity, nationality and geography. We used interviews, observation-based assessments, and the Geographic Information System to assess a population of 8,783 seasonal migrants and 1,099 temporary dwellings at a total of 520 farms during 2004-2005. We identified determinants of poor health including widespread deficiencies in the quality of grower-provided dwellings, geographical isolation, crowding, lack of radio and television, and deficient toilets and cooking facilities. The indigenous and non-Costa Ricans shared the poorest conditions. Reluctance to use mainstream public health services was widespread, especially among foreign and indigenous migrants and the geographically isolated. Post-study, researchers organized workshops for audiences including workers, coffee producers, public officials and service providers. Topics have included migration, preventive health and hygiene, and child labor. This work was successful in convincing Costa Rican social security authorities to implement reforms that improve access to and quality of health care for the migrants. Special projects on ergonomics, psychosocial health hazards, and water quality, as well as a literacy program, are ongoing.

Parental occupational exposure to pesticides and the risk of childhood leukemia in Costa Rica

OBJECTIVES

Parental exposure to pesticides and the risk of leukemia in offspring were examined in a population-based case-control study in Costa Rica.

METHODS

All cases of childhood leukemia (N=334), in 1995-2000, were identified at the Cancer Registry and the Children's Hospital. Population controls (N=579) were drawn from the National Birth Registry. Interviews of parents were conducted using conventional and icon-based calendar forms. An exposure model was constructed for 25 pesticides in five time periods.

RESULTS

Mothers' exposures to any pesticides during the year before conception and during the first and second trimesters were associated with the risk [odds ratio (OR) 2.4, 95% confidence interval (95% CI) 1.0-5.9; OR 22, 95% CI 2.8-171.5; OR 4.5, 95% CI 1.4-14.7, respectively] and during anytime (OR 2.2, 95% CI 1.0-4.8). An association was found for fathers' exposures to any pesticides during the second trimester (OR 1.5, 95% CI 1.0-2.3). An increased risk with respect to organophosphates was found for mothers during the first trimester (OR 3.5, 95% CI 1.0-12.2) and for fathers during the year before conception and the first trimester (OR 1.5, 95% CI 1.0-2.2 and OR 1.6, 95% CI 1.0-2.6, respectively), and benzimidazoles during the first, second, and third trimesters of pregnancy (OR 2.2, 95% CI 1.0-4.4; OR 2.2, 95% CI 1.0-5.0; OR 2.2, 95% CI 1.0-5.2, respectively). There was a suggestion of an exposure-response gradient for fathers as regards picloram, benomyl, and paraquat. Age at diagnosis was positively associated with fathers' exposures and inversely associated with mothers' exposures.

CONCLUSIONS

The results suggest that parental exposure to certain pesticides may increase the risk of leukemia in offspring.

Polycyclic Aromatic Hydrocarbons and Fatal Ischemic Heart Disease

BACKGROUND

Several toxicologic and epidemiologic studies have produced evidence that occupational exposure to polycyclic aromatic hydrocarbons (PAH) is a risk factor for ischemic heart disease (IHD). However, a clear exposure-response relation has not been demonstrated.

METHODS

We studied a relation between exposure to PAH and mortality from IHD (418 cases) in a cohort of 12,367 male asphalt workers from Denmark, Finland, France, Germany, Israel, The Netherlands and Norway. The earliest follow up (country-specific) started in 1953 and the latest ended in 2000, averaging 17 years. Exposures to benzo(a)pyrene were assessed quantitatively using measurement-driven exposure models. Exposure to coal tar was assessed in a semiquantitative manner on the basis of information supplied by company representatives. We carried out sensitivity analyses to assess potential confounding by tobacco smoking.

RESULTS

Both cumulative and average exposure indices for benzo(a)pyrene were positively associated with mortality from IHD. The highest relative risk for fatal IHD was observed for average benzo(a)pyrene exposures of 273 ng/m or higher, for which the relative risk was 1.64 (95% confidence interval=1.13-2.38). Similar results were obtained for coal tar exposure. Sensitivity analysis indicated that even in a realistic scenario of confounding by smoking, we would observe approximately 20% to 40% excess risk in IHD in the highest PAH-exposure categories.

CONCLUSIONS

Our results lend support to the hypothesis that occupational PAH exposure causes fatal IHD and demonstrate a consistent exposure-response relation for this association.

Determinación del historial de exposiciones en la epidemiolgía ocupacional

In epidemiology, it is necessary that exposure indicators have good validity in order to obtain valid results when measuring the risks associated with occupational exposure to environmental noxious agents. However, ensuring the validity of past exposure data is no easy task. Because there are no environmental hygiene measures or representative levels of bioindicators signaling past exposure, self-reports have been used as a source of indirect exposure data. Unfortunately, data on specific agents are commonly poor and need to be complemented with data on the determinants of exposure. The validity of self-reports improves when certain techniques, such as control lists and icons, are employed, and the quality of individual exposure data improves when secondary data on exposure and its conditioning or determining factors are incorporated. Exposure can be determined by means of exposure matrices, assessment by experts, and exposure models, and by using a combination of primary and secondary data on exposure and its conditioning factors. Matrices contain pooled data and can thus lead to errors in classifying individual exposure and to biased risk estimates. Assessment by experts is probably the method with the highest validity, but it can become expensive when studies are large. It is also feasible to use a formal model for assessing perceivable exposures, complemented with expert assessments whenever the results of the model appear to deviate from reality.

Pesticide prioritization for a case-control study on childhood leukemia in Costa Rica: a simple stepwise approach

Multiple exposures and rapidly changing use patterns are obstacles for adequate recall of pesticide exposures in epidemiologic studies. We present a simple stepwise approach for prioritization of pesticides as part of the exposure assessment strategy in an ongoing case-control study on pesticides and childhood leukemia in Costa Rica. Pesticide imports between 1977 and 2000, approximately the pertinent exposure period, were surrogates for use data. In the first phase, 323 active ingredients were identified, of which 219 were eliminated based on low usage and absence or negative results in a preliminary search in three major toxicity databases. In the second phase, the remaining 104 pesticides underwent scoring for their toxicodynamic potential (TDP) with regard to carcinogenicity, mutagenicity, and teratogenicity, weighted in this order. Bioavailability was assessed when TDP was multiplied by a weight for persistence and bioaccumulation, producing the intrinsic toxic potential (ITP). ITP was multiplied by an index of quantity (QI) of pesticide used in the exposure period, resulting in a weighted toxic potential (WTP). The top 25 positions in each of the four rankings (TDP, ITP, QI, and WTP) yielded together 64 highest-priority pesticides. This prioritization process has to be complemented with a further breakdown into crop-, time-, and biocide-specific shortlists to achieve a recall tool suitable for developing countries. Different parameters for prioritization assure inclusion of all relevant pesticides with regard to toxicity and bioavailability. The method contributes to cancer epidemiology in developing countries with access to basic use data and the Internet. The method is adaptable to other health outcomes.

Central nervous system effects of acute organophosphate poisoning in a two-year follow-up

OBJECTIVES

Patients hospitalized for acute organophosphate poisoning in León, Nicaragua, were followed for effects on the central nervous system (CNS) over a 2-year period.

METHODS

Immediate verbal memory (Rey verbal learning), visuomotor performance (digit symbol), and neuropsychiatric symptoms (Q-16) were assessed for 53 poisoned persons at the time of hospital discharge, 7 weeks postpoisoning, and 2 years postpoisoning, and, at the same time intervals, for 28 persons who had never been poisoned. The poisonings were classified as moderate occupational (31), severe occupational (15), and severe through the oral route (7), representing low, medium, and high exposure, respectively. Longitudinal confounder-adjusted between-category comparisons and longitudinal analyses of variance and covariance were used to assess the effects of the exposure.

RESULTS

Immediate verbal learning showed deficits in the high-exposure group, in particular at the time of discharge, but the estimate of the difference when compared with the values of the unexposed was imprecise. Visuomotor performance showed a deficit at 7 weeks in the medium-exposure group, but it had improved after 2 years relative to that of the unexposed, for whom improvement had occurred at 7 weeks and persisted during the 2 years of follow-up, possibly a test-retest effect. Neuropsychiatric symptoms were in excess 2 years after the hospital discharge in the low- and medium-exposure groups and all the groups combined. All the results were imprecise for the small high-exposure group.

CONCLUSIONS

Visuomotor performance and possibly short-term verbal memory seem to be affected early after severe acute organophosphate poisoning and recover, either truly or by some compensatory mechanism. Neuropsychiatric symptoms seem to increase after a longer latency period.

Assessment of pesticide exposure in the agricultural population of Costa Rica

We describe a model for the retrospective assessment of parental exposure to 26 pesticides, selected by toxicity-based prioritization, in a population-based case-control study of childhood leukaemia in Costa Rica (301 cases, 582 controls). The model was applied to a subset of 227 parents who had been employed or self-employed in agriculture or livestock breeding. It combines external data on pesticide use for 14 crops, 21 calendar years and 14 regions, and individual interview data on determinants (task and technology, personal protective equipment, field reentry, storing of pesticides, personal hygiene) of exposure. Recall was enhanced by use of checklists of pesticides in the interview. An external database provided information on the application rate (proxy for intensity of potential exposure) for each pesticide. The calendar time was individually converted to five time windows (year before conception, first, second and third trimester, and first year of the child). Time-windowed individual data on determinants of exposure and their expert-based general weights and their category-specific hazard values jointly provided an individual determinant score. This score was multiplied by the application rate to obtain an individual index of exposure intensity during application. Finally, average exposure intensity during entire time windows was estimated by incorporating in the model the individual time fraction of exposure during application. Estimates of exposure intensities were proxies assumed to be proportional to dermal exposure intensity, which represents the major pathway of occupational exposure to pesticides. A simulated sensitivity analysis resulted in a correlation coefficient of 0.91 between two sets of 10 000 values of individual exposure indices, based on two different but realistic sets expert-assigned weights. Lack of measurement data on concurrent exposures in comparable circumstances precluded direct validation of the model.

Cancer incidence of Nordic asphalt workers

OBJECTIVES

The aim of the study was to investigate cancer risk following employment in the asphalt industry.

METHODS

Cancer incidence was studied among 22 362 male asphalt workers employed for more than one season in jobs entailing exposure to bitumen (mainly road pavers) in Denmark, Finland, Norway, and Sweden. These workers are part of a European cohort of asphalt workers, for which results on mortality have been reported. The follow-up was almost complete, and reference rates were obtained from national cancer registries.

RESULTS

The incidence of cancer was reduced in all four countries [overall standardized incidence ratio (SIR) 0.89, 95% confidence interval (95% CI) 0.86-0.94]. Lung cancer incidence was increased in all four countries, yielding an overall SIR of 1.21 (95% CI 1.07-1.36), but no trend was detected according to time since first employment. No overall increased incidence of bladder cancer was observed, but there was a suggestion of a tendency towards higher risk with longer time since first employment, with a relative risk of 1.85 (95% CI 0.90-3.78) for more than 30 years versus 1-14 years (P-value for trend 0.1). The incidence of lip and stomach cancer was nonsignificantly increased, and the excess was present mainly in Denmark. No increased incidence was detected for other neoplasms, notably malignant melanoma, nonmelanoma skin cancer, and kidney cancer.

CONCLUSIONS

The results of this study confirm the pattern of cancer risk detected in the mortality analysis of the European cohort; in addition, they provide suggestive evidence of an excess risk of bladder cancer among asphalt workers.

Pesticide patch test series for the assessment of allergic contact dermatitis among banana plantation workers in panama

BACKGROUND

Irritant contact dermatitis and allergic contact dermatitis (ACD) are frequent among agricultural workers and require targeted interventions. Patch testing is necessary for differential diagnosis, but patch testing with pesticides is uncommon.

OBJECTIVE

This study explores the frequency of ACD and sensitization to pesticides among highly exposed banana plantation workers.

METHODS

Frequently and recently used pesticides on banana plantations in Divala, Panama, were documented. A pesticide patch test tray specific for this population was prepared. A structured interview was administered to 366 participants, followed by a complete skin examination. The pesticide patch test series, as well as a standard patch test series, was applied to 37 workers with dermatoses likely to be pesticide related and to 23 control workers without dermatoses.

RESULTS

The pesticide patch tests identified 15 cases (41%) of ACD (20 positive reactions) among the 37 workers diagnosed with pesticide dermatosis. Three controls had allergic reactions to pesticides (4 positive reactions). The pesticides were carbaryl (5 cases), benomyl (4 cases), ethoprophos (3), chlorothalonil (2), imazalil (2), glyphosate (2), thiabendazole (2), chlorpyrifos (1), oxyfluorfen (1), propiconazole (1), and tridemorph (1). Ethoprophos and tridemorph had not been previously identified as sensitizers. Thus, the prevalence of ACD was 0.03 (15 of 366). On the basis of observed prevalences of positive patch-test reactions among the subgroups with and without dermatoses, we estimated that > or = 16% of the entire population may be sensitized to pesticides.

CONCLUSION

Sensitization to pesticides among banana plantation workers is a frequent occupational health problem. Pesticide patch test trays should be used in assessing skin diseases in highly exposed workers.

Risk of fatal industrial accidents and death from other external causes among asphalt workers

The hypothesis that asphalt workers are at increased risk of mortality from industrial accidents and other external causes was tested. Mortality rates for external and violent causes of death in a cohort of asphalt industry employees from seven European countries and Israel were compared to that of the general population. There was no evidence that mortality from external causes was increased among long term employees in asphalt application and mixing. There was an increased risk for mortality due to external causes among short term workers. However, none of the fatal accidents among short term workers appear to have occurred during employment in the studied asphalt companies. Overall, no evidence was found supporting the hypothesis that asphalt workers are at increased risk of fatal industrial or road accidents. Mortality from other external causes did not increase in this population as a whole, but increased risks among short term workers deserve further attention.

Mortality from obstructive lung diseases and exposure to polycyclic aromatic hydrocarbons among asphalt workers

Work in the asphalt industry has been associated with nonmalignant respiratory morbidity and mortality, but the evidence is not consistent. A historical cohort of asphalt workers included 58,862 men (911,209 person-years) first employed between 1913 and 1999 in companies applying and mixing asphalt in Denmark, Finland, France, Germany, Israel, the Netherlands, and Norway. The relations between mortality from nonmalignant respiratory diseases (including the obstructive lung diseases: chronic bronchitis, emphysema, and asthma) and specific chemical agents and mixtures were evaluated using a study-specific exposure matrix. Mortality from obstructive lung diseases was associated with the estimated cumulative and average exposures to polycyclic aromatic hydrocarbons and coal tar (p values of the test for linear trend = 0.06 and 0.01, respectively). The positive association between bitumen fume exposure and mortality from obstructive lung diseases was weak and not statistically significant; confounding by simultaneous exposure to coal tar could not be excluded. The authors lacked data on smoking and full occupational histories. In conclusion, exposures to polycyclic aromatic hydrocarbons, originating from coal tar and possibly from bitumen fume, may have contributed to mortality from obstructive lung diseases among asphalt workers, but confounding and bias cannot be ruled out as an explanation for the observed associations.

Social context for workplace health promotion: feasibility considerations in Costa Rica, Finland, Germany, Spain and Sweden

We constructed a simple, flexible procedure that facilitates the pre-assessment of feasibility of workplace health promotion (WHP) programmes. It evaluates cancer hazards, workers' need for hazard reduction, acceptability of WHP, and social context. It was tested and applied in 16 workplace communities and among 1085 employees in industry, construction, transport, services, teaching and municipal works in Costa Rica, Finland, Germany, Spain and Sweden. Social context is inseparable from WHP. It covers workers' organizations and representatives, management, safety committees, occupational health services, health and safety enforcement agencies, general health services, non-government organizations, insurance systems, academic and other institutions, regulatory stipulations pertaining WHP, and material resources. Priorities, risk definitions, attitudes, hazard profiles, motivations and assessment methods were highly contextual. Management preferred passive interventions, helping cover expert costs, participating in planning and granting time. Trade unions, workers' representatives, safety committees and occupational health services appeared to be important operational partners. Occupational health services may however be loaded with curative and screening functions or be non-existent. We advocate participatory, multifaceted WHP based on the needs and empowerment of the workers themselves, integrating occupational and lifestyle hazards. Workforce in irregular and shift work, in agriculture, in small enterprises, in the informal sector, and immigrant, seasonal and temporary workers represent groups in need of particular strategies such as community health promotion. In a more general framework, social context itself may become a target for intervention.

Workplace carcinogen and pesticide exposures in Costa Rica

The CAREX data system converts national workforce volumes and proportions of workers exposed to workplace carcinogens into numbers of exposed in 55 industrial categories. CAREX was adapted for Costa Rica for 27 carcinogens and seven groups of pesticides. Widespread workplace carcinogens in the 1.3 million workforce of Costa Rica are solar radiation (333,000 workers), diesel engine exhaust (278,000), environmental tobacco smoke (71,000), hexavalent chromium compounds (55,000), benzene (52,000), wood dust (32,000), silica dust (27,000), lead and inorganic lead compounds (19,000), and polycyclic aromatic compounds (17,000). The most ubiquitous pesticides were paraquat and diquat (175,000), mancozeb, maneb, and zineb (49,000), chlorothalonil (38,000), benomyl (19,000), and chlorophenoxy herbicides (11,000). Among women, formaldehyde, radon, and methylene chloride overrode pesticides, chromium, wood dust, and silica dust in numbers of exposed. High-risk sectors included agriculture, construction, personal and household services, land and water transport and allied services, pottery and similar industries, woodworks, mining, forestry and logging, fishing, manufacturing of electrical machinery, and bar and restaurant personnel.

Occupational exposures and gastrointestinal cancers among Finnish women

A cohort including all female workers born 1906 through 1945 (n = 413,877) in Finland was identified through the Population Census of Finland of 1970. Incident cases of cancers of the gastrointestinal tract were explored during 1971 to 1995. Job titles in census records were converted to exposures of 31 occupational agents through a job-exposure matrix. For each agent, the product of level and probability of exposures was calculated and subdivided in three categories: zero, low and medium/high. Poisson regression models estimated relative risks (RR) for each agent, standardized for birth cohort, follow-up period, and socioeconomic status. Adjustment at job title level was done for alcohol use for cancers of the esophagus and liver and smoking for pancreatic cancer. The results showing either statistically significant RR at the medium/high level of exposure (RRH) or statistically significant trend (P < 0.05) over the exposure categories were considered as positive findings. Colon cancer risk (2009 cases) was positively associated with sedentary work (RRH 1.3, 95% CI = 1.1-1.6; P trend 0.001) and negatively associated with perceived workload (P trend = 0.007). For stomach cancer (1881 cases), we observed an association with exposure to electromagnetic fields (RRH 1.44, 95% CI = 1.01-2.05) and man-made vitreous fibers (MMVF) (p trend 0.03). Rectal cancer (1323 cases) showed an association with chromium (RRH 1.9, 95% CI = 1.2-3.1) and oil mist (RR 2.0; 95% CI = 1.0-3.9). For pancreas cancer (1302 cases) we found associations with exposure to chromium (RRH 1.8; 95% CI = 1.0-3.1; P trend 0.01), electromagnetic fields (RRH 1.8; 95% CI = 1.2-2.8; P trend 0.02), and sedentary work (RRH 1.3; 95% CI = 1.0-1.7; P trend 0.05). We found no significant associations between any FINJEM agents and cancers of the esophagus (389 cases), liver (389 cases), and gallbladder (651 cases). Having examined the associations between seven cancer sites and over 30 exposures there exists the real possibility that some of the associations detected are chance findings. Therefore, the associations observed should need to be confirmed in other studies.

Estimating exposures in the asphalt industry for an international epidemiological cohort study of cancer risk

BACKGROUND

An exposure matrix (EM) for known and suspected carcinogens was required for a multicenter international cohort study of cancer risk and bitumen among asphalt workers.

METHODS

Production characteristics in companies enrolled in the study were ascertained through use of a company questionnaire (CQ). Exposures to coal tar, bitumen fume, organic vapor, polycyclic aromatic hydrocarbons, diesel fume, silica, and asbestos were assessed semi-quantitatively using information from CQs, expert judgment, and statistical models. Exposures of road paving workers to bitumen fume, organic vapor, and benzo(a)pyrene were estimated quantitatively by applying regression models, based on monitoring data, to exposure scenarios identified by the CQs.

RESULTS

Exposures estimates were derived for 217 companies enrolled in the cohort, plus the Swedish asphalt paving industry in general. Most companies were engaged in road paving and asphalt mixing, but some also participated in general construction and roofing. Coal tar use was most common in Denmark and The Netherlands, but the practice is now obsolete. Quantitative estimates of exposure to bitumen fume, organic vapor, and benzo(a)pyrene for pavers, and semi-quantitative estimates of exposure to these agents among all subjects were strongly correlated. Semi-quantitative estimates of exposure to bitumen fume and coal tar exposures were only moderately correlated. EM assessed non-monotonic historical decrease in exposures to all agents assessed except silica and diesel exhaust.

CONCLUSIONS

We produced a data-driven EM using methodology that can be adapted for other multicenter studies.

Cancer mortality among European asphalt workers: an international epidemiological study. I. Results of the analysis based on job titles

BACKGROUND

Inhalation of bitumen fumes is potentially carcinogenic to humans.

METHODS

We conducted a study of 29,820 male workers exposed to bitumen in road paving, asphalt mixing and roofing, 32,245 ground and building construction workers unexposed to bitumen, and 17,757 workers not classifiable as bitumen workers, from Denmark, Finland, France, Germany, Israel, the Netherlands, Norway, and Sweden, with mortality follow-up during 1953-2000. We calculated standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) based on national mortality rates. Poisson regression analyses compared mortality of bitumen workers to that of building or ground construction workers.

RESULTS

The overall mortality was below expectation in the total cohort (SMR 0.92, 95% CI 0.90-0.94) and in each group of workers. The SMR of lung cancer was higher among bitumen workers (1.17, 95% CI 1.04-1.30) than among workers in ground and building construction (SMR 1.01, 95% CI 0.89-1.15). In the internal comparison, the relative risk (RR) of lung cancer mortality among bitumen workers was 1.09 (95% CI 0.89-1.34). The results of cancer of the head and neck were similar to those of lung cancer, based on a smaller number of deaths. There was no suggestion of an association between employment in bitumen jobs and other cancers.

CONCLUSIONS

European workers employed in road paving, asphalt mixing and other jobs entailing exposure to bitumen fume might have experienced a small increase in lung cancer mortality risk, compared to workers in ground and building construction. However, exposure assessment was limited and confounding from exposure to carcinogens in other industries, tobacco smoking, and other lifestyle factors cannot be ruled out.

Cancer mortality among European asphalt workers: an international epidemiological study. II. Exposure to bitumen fume and other agents

BACKGROUND

An increased risk of lung cancers among asphalt workers has been suggested in epidemiological studies based on large scale statistical analyses.

METHODS

In a multi-country study of 29,820 male workers employed in road paving, asphalt mixing and roofing, 32,245 ground and building construction workers and 17,757 other workers from Denmark, Finland, France, Germany, Israel, the Netherlands, Norway, and Sweden, with mortality that was documented from 1953-2000. Exposures to bitumen fume, coal tar, 4-6 ring polycyclic aromatic hydrocarbons, organic vapor, diesel exhaust, asbestos, and silica dust were assessed via a job-exposure matrix. Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) based on national mortality rates, as well as relative risks (RRs) based on Poisson regression models were calculated.

RESULTS

The SMR of lung cancer among workers exposed to bitumen fume (1.08, 95% CI 0.99-1.18) was comparable to that of non-exposed workers (SMR 1.05, 95% CI 0.92-1.19). In a sub-cohort of bitumen-exposed workers without exposure to coal tar, the SMR of lung cancer was 1.23 (95% CI 1.02-1.48). The analysis based on the semi-quantitative, matrix-based exposures in the whole cohort did not suggest an increased lung cancer risk following exposure to bitumen fume. However, in an analysis restricted to road pavers, based on quantitative estimate of bitumen fume exposure, a dose-response was suggested for average level of exposure, applying a 15-year lag, which was marginally reduced after adjustment for co-exposure to coal tar. The results for cancer of the head and neck were similar to those of lung cancer, although they were based on a smaller number of deaths. There was no clear suggestion of an association with bitumen fume for any other neoplasm.

CONCLUSIONS

The results of the analysis by bitumen fume exposure do not allow us to conclude on the presence or absence of a causal link between exposure to bitumen fume and risk of cancer of the lung and the head and neck.

Performance of different exposure assessment approaches in a study of bitumen fume exposure and lung cancer mortality

BACKGROUND

We compared performance of different exposure assessment approaches in a cohort study of cancer risk among European asphalt workers.

METHODS

Three bitumen fume exposure indices (duration of exposure (years), average exposure (mg/m3) and cumulative exposure (mg/m3*years)) and two latency models (with and without a 15 year lag) were considered for an association between lung cancer mortality and bitumen fume.

RESULTS

There was no association between lung cancer risk and either duration or cumulative exposure. However, there was the suggestion of an increase in lung cancer risk accompanying rise in average exposure. Only models with average bitumen fume exposure (with or without lag) improved model fit, albeit to the same extent.

CONCLUSIONS

Constructing quantitative indices of exposure intensity was justified because they produced the greatest improvement in fit of models that explored possible relationship between bitumen fume exposure and lung cancer risk. The identified associations require further investigation.

Epidemiologic study of cancer mortality among Israeli asphalt workers

BACKGROUND

We describe the results of a cancer mortality study among asphalt workers in Israel.

METHODS

Personal identifiers and employment histories of 2,176 workers were extracted from company records.

RESULTS

Mortality from all malignant neoplasms was significantly reduced in the whole cohort (SMR 0.68, 95% confidence interval (CI) 0.56-0.83). SMR for lung cancer was elevated in workers exposed to bitumen (SMR 1.05, 95% CI 0.62-1.66). No significant elevation or reduction in mortality was observed in relation to a specific site. SMRs for lung cancer was higher among ever exposed to bitumen than among unexposed. There was no association between lung cancer risk and estimated exposure to bitumen fume, and no dose-response was apparent.

CONCLUSIONS

While the results of this cohort study indicate a slightly increased SMR for lung cancer, it did not produce evidence of a causal link between lung cancer and exposure to bitumen fume.

Mortality and cancer incidence of workers in Finnish road paving companies

BACKGROUND

This study, a component of the International Agency for Research on Cancer (IARC) Multicentric Study on Cancer Risk Among European Asphalt Workers, aimed at identifying major mortality risks among workers in Finnish road paving companies.

METHODS

The Finnish cohort was comprised of 9,643 men and women from six road paving companies. The mortality of men employed during at least one season (5,676) was followed up from 1964 until end of 1994; an average of 17 years. Standardized mortality ratios (SMR) and relative risks (RR), the latter based on multivariate Poisson regression models were estimated by occupational group and by various metrics of occupational exposures.

RESULTS

All-cause mortality was elevated (SMR 1.11, 95% confidence interval, CI 1.03-1.20), mainly due to excesses in accidents, poisonings, and violence (1.29; CI 1.12-1.49), and lung cancer (1.38; 1.03-1.81). Workers exposed to bitumen fumes had a slightly elevated mortality from lung cancer (1.16; 0.69-1.83). Multivariate Poisson regression models with 15-year lag period suggested trends by cumulative exposure to coal tar, organic vapors, silica dust, diesel exhaust, and bitumen fume.

CONCLUSIONS

The elevated mortality from external causes among Finnish building/ground construction workers was probably due to living conditions and related lifestyles. Some evidence was found for a risk of lung cancer due to occupational exposure, but the confirmation of these findings would require a longer follow-up and improved control for confounding.

[Employees attitudes to workplace health promotion programs for cancer prevention]

OBJECTIVE

[corrected] We describe a method for feasibility assessment of workplace health promotion (WHP) programs as a necessary prerequisite of any WHP program.

METHODS

A total of 167 employees from five workplace communities participated in the study. A questionnaire on the basic components of feasibility (risk factors, attitudes to workplace health promotion interventions, and social-occupational context) was administered.

RESULTS

Risk behaviours were common among the employees interviewed. Health promotion in the workplace was favorably viewed by 79% of subjects but reported participation would be lower. Interventions on diet and physical activity received the highest acceptance. Participation would be greatest among local administration employees.

CONCLUSIONS

The method demonstrated its utility in obtaining useful data for designing workplace health promotion interventions.

Assessment of feasibility of workplace health promotion

BACKGROUND

A simple empirically based method for assessment of the feasibility of workplace health promotion programs is described, focusing on cancer hazards (lifestyles, workplace hazards, deficient early detection). The basic components of feasibility are addressed: extent of hazards; needs of employees for hazard reduction and acceptability of WHP; and social context.

METHODS

The procedure consists of six modules: guidelines on feasibility assessment; employee questionnaire; interview checklists for probing attitudes of management and partners (social context); data form; debriefing; and assessment of feasibility. Pretesting was completed in 16 workplace communities representing industry, construction, transport, telecommunications, health care, lodging and catering, teaching, and municipality jobs in five countries; a total of 1,085 subjects completed the employee questionnaire on health hazards, needs, and acceptability.

RESULTS

The method demonstrated its utility in obtaining and summarizing the necessary data. Feasibility was assessed for the 16 test communities.

CONCLUSION

The procedure can be customized; it has a high degree of face validity or understandability, and it is applicable in a wide variety of settings.

Childhood leukaemia in Costa Rica, 1981-96

Childhood leukaemia incidence in Costa Rica during 1981-96, among the highest in the world, was analysed by histology, gender, birth year, time period of diagnosis, age at diagnosis and region. Numbers of cases were extracted from the database of the National Cancer Registry (RNT) of Costa Rica. Person-years at risk were calculated from census data and post-census population estimates. During the follow-up, 918 cases of leukaemia in children under 15 years (510 boys, 408 girls) were reported to the RNT (41% of all childhood malignancies), with an overall age-standardised incidence rate of 56 per million person-years. Acute lymphocytic leukaemia (ALL) represented 79% and acute non-lymphocytic leukaemia (ANLL) 16% of the cases, with rates of 43 and 9 per million person-years respectively. There were downward trends in incidence of total leukaemias, ALL and ANLL and 'not otherwise specified' (NOS) combined. Incidence of ALL was highest at 1-4 years of age in boys and girls, whereas ANLL peaked in girls during the first year of life. During 1991-96, the decrease in ALL was significant (P = 0.042). A multivariable Poisson regression model identified significant excesses of ALL for boys, for age groups 1-4 and 5-9 years and for three out of seven regions. Possible reasons for the high rates in Costa Rica are discussed.

Cancer of the brain and nervous system and occupational exposures in Finnish women

Occupational agents were evaluated for the risk of brain-nervous system cancer in a cohort of 413,877 Finnish women with blue-collar occupations in 1970. Observed and expected numbers of incident cases and the intensities of exposure to 25 agents were generated for 183 job titles from 1971 to 1995. Poisson regression models linked incidence and exposure data. Increased risks were found for medium/high intensities of iron (standardized incidence ratio [SIR], 2.15; 95% confidence interval [CI], 0.96 to 4.80), oil mist (1.95; 0.97 to 3.90), any chromium compounds (1.51; 0.85 to 2.67), electromagnetic fields (1.37; 0.98 to 2.10), aliphatic and alicyclic hydrocarbon compounds (1.34; 0.80 to 2.27), lead (1.27; 0.81 to 2.01), cadmium (1.26; 0.72 to 2.22), and aromatic hydrocarbon compounds (1.20; 0.71 to 2.03). Strengths of the study include fair number of cases, virtually complete case coverage, and a high-quality job exposure matrix. Ecological design and cross-sectional job assessment introduced exposure misclassification and tended to drive risk estimates toward unity.

Role of trade unions in workplace health promotion

Since the 19th century, workers have organized in trade unions and parties to strengthen their efforts at improving workplace health and safety, job conditions, working hours, wages, job contracts, and social security. Cooperation between workers and their organizations and professionals has been instrumental in improving regulation and legislation affecting workers' health. The authors give examples of participatory research in occupational health in Denmark and Finland. The social context of workplace health promotion, particularly the role of unions and workers' safety representatives, is described in an international feasibility study. Health promotion is rife with fundamental political, socioeconomic, philosophical, ethical, gender- and ethnicity-related, psychological, and biological problems. Analysis of power and context is crucial, focusing on political systems nationally, regionally, and globally. The authors advocate defending and supporting workers and their trade unions and strengthening their influence on workplace health promotion. In the face of rapid capitalist globalization, unions represent a barricade in defense of workers' health and safety. Health promoters and related professionals are encouraged to support trade unions in their efforts to promote health for workers and other less privileged groups.

Occupational health in Central America

The 12.4 million economically active population (EAP) of the seven Central American countries includes a large informal sector. Social security covers only 14-60%. No surveillance of occupational safety and health (OSH) hazards or accidents exists. Extrapolating the incidence of occupational accidents among insured Costa Rican workers to the Central American EAP yields two million accidents yearly, still a gross underestimate. Occupational diseases are underreported, misdiagnosed, and not recognized as such. A number of regional OSH programs aim at modernization of the labor administrations and address the formal sector, in particular textile maquila, in connection with free trade agreements. The weak role of the ministries of health is expected to strengthen under the Pan American Health Organization OSH program. Employers largely influence new policies. Workers' influence on OSH policies has been weak, with only about 10% unionization rate and scarce resources and OSH knowledge. Informal workers, however, are getting organized. OSH research is underdeveloped and not linked to policy making. Construction, agriculture, and general un/underemployment are considered priorities for intervention. The informal sector needs to be included in national and regional OSH policies. Regional collaboration and international development support are of strategic importance to achieve sustainable improvement in OSH.

Occupational exposure to organic solvents and K-ras mutations in exocrine pancreatic cancer

Occupational exposure to hydrocarbon solvents has been found to be associated with an increased risk of exocrine pancreatic cancer (EPC), the human tumor with the highest prevalence of K-ras mutations. Ras genes are critical DNA targets for chemical carcinogens. We analysed the relationship between past occupational exposure to hydrocarbon solvents and mutations in codon 12 of the K-ras gene in 107 incident cases of EPC. Information on occupational factors and life-style was obtained from personal interviews conducted during hospital stay. Occupational exposure to hydrocarbon solvents (aliphatic, aromatic, chlorinated, benzene, other organic solvents) was examined using two methods: expert assessment and the Finnish job-exposure matrix (Finjem). Exposure among K-ras mutated EPC cases (n = 83) was compared with that of K-ras wild-type EPC cases (n = 24). An association between K-ras mutations and solvent exposure was observed with Finjem but barely so with the expert assessment. Over 7-fold increased odds ratios (OR) were found for every group of solvents evaluated with Finjem (all P < 0.05). On the basis of the expert assessment, K-ras mutations were significantly associated only with exposure to benzene in men (OR = 7.07, P < 0.05). When requiring exposure to have occurred according to both the experts and Finjem, over 4-fold risks were obtained for aromatic, aliphatic, and for "any hydrocarbon solvent". A significantly higher proportion of cases with a mutation from glycine to valine (GGT-->GTT) or to aspartic acid (GGT-->GAT) were exposed to a hydrocarbon solvent. The results raise the possibility that hydrocarbon solvents might be involved in the pathogenesis of EPC, possibly through indirect modulation of K-ras activation. Since this is only the first study on occupational exposures and K-ras mutations in EPC, studies able to refute or to confirm the findings are required before public health implications, if any, are assessed.

Occupational exposures and cancers of the endometrium and cervix uteri in Finland

BACKGROUND

Endometrial cancer incidence rates are low in Asia and Africa and high in North America and Northern Europe. Cervical cancer is often the most common female cancer in developing countries, and infection with human papillomavirus (HPV) is its main risk factor. However, other factors, such as occupational exposures may modify the HPV-related risk. We conducted an exploratory register-linkage study in Finland to assess the role of occupational exposures on incidence rates of cancers of the endometrium and cervix uteri.

METHODS

Occupational risk factors for endometrial and cervical cancers were explored in a 25-year follow-up of female workers born 1906-1945 (N = 413,877) identified through the Population Census of Finland of 1970. Job titles in census records were converted to exposures of 31 occupational agents through a job-exposure matrix. Poisson regression models estimated relative risks (RR) for each agent, standardized for birth cohort, follow-up period, and socio-economic status. For each agent, the product of level and probability of exposure was calculated and subdivided in three categories: zero, low, and medium/high. Adjustment at the job title level was done for the turnover rate (endometrial and cervical cancers), mean parity, and age at first birth (endometrial cancer).

RESULTS

Endometrial cancer (2,833 cases) was associated with exposure to animal dust (RR 1.2, low level, 174 cases) and sedentary work (RR 1.3, high level, 145 cases). Cervical cancer (1,101 cases) was associated with exposure to aliphatic and alicyclic (RR 1.3, low level, 91 cases), aromatic (RR 1.2, low level, 318 cases; RR 1.4, high level, 41 cases), and chlorinated hydrocarbon solvents (RR 1.3, low level, 50 cases), silica dust (RR 1.2, low level, 251 cases), and wood dust (RR 1.2, low level, 249 cases).

CONCLUSIONS

This study suggests that occupational exposures may be associated with increased risk of endometrial and cervical cancers.

Lymphangiogenesis and the vascular endothelial growth factor receptor (VEGFR)-3 in gastric cancer

Vascular endothelial growth factor C (VEGF-C) is the only factor known to cause lymphangiogenesis. We studied the correlation between VEGF-C and vascular endothelial growth factor receptor-3 (VEGFR-3) expression of 85 primary gastric cancers by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry, and the results were correlated with the number of lymphatic vessels, stained with anti-VEGFR-3 antibody. RT-PCR and immunohistology demonstrated that VEGF-C was mainly produced from cancer cells, but not from stromal elements. Morphologically, VEGFR-3 expression was detected in the endothelial cells of the stromal lymphatic vessels. There was a statistically positive correlation between the incidence of VEGF-C and VEGFR-3 mRNA expression in the primary tumours (P=0.0002). The number of VEGFR-3-positive lymphatic vessels in VEGF-C mRNA positive tumours was significantly larger than that in VEGF-C-negative tumours. The number of VEGFR-3-positive vessels in the tumour stroma was closely related to the grade of lymphatic invasion of gastric cancer. These results strongly indicate that VEGF-C may induce the proliferation of lymphatic vessels in the stroma of primary gastric cancer via activation of VEGFR-3, expressed on the endothelial cells of lymphatic vessels. In these circumstances, cancer cells can easily invade the lymphatic vessel, because of the increase of the contact points of cancer cells with the lymphatic vessels.

Risk of pancreatic cancer in workers exposed to chlorinated hydrocarbon solvents and related compounds: a meta-analysis

This is a meta-analysis of occupational exposures to chlorinated hydrocarbon (CHC) solvents and pancreatic cancer, based primarily on studies that addressed exposure directly (agent studies) and secondarily on studies that reported data without verification of individual CHC exposures (job title studies), all of which were listed in databases for the period January 1969 to May 1998. Standardized extraction of data and double-checking of consistency of data extraction by five extractors were done. Simple random models estimated meta-relative risks. Suggestive weak excesses were found for trichloroethylene (meta-relative risk (MRR) = 1.24, 95% confidence interval (CI): 0.79, 1.97), polychlorinated biphenyls (MRR = 1.37, 95% CI: 0.56, 3.31), methylene chloride (MRR = 1.42, 95% CI: 0.80, 2.53), and vinyl chloride (MRR = 1.17, 95% CI: 0.71, 1.91) but not for carbon tetrachloride. One study addressed tetrachloroethylene (MRR = 3.08, 95% CI: 0.63, 8.99); another investigated chlorohydrin production (MRR = 4.92, 95% CI: 1.58, 11.4). Exposure-response meta-analyses for trichloroethylene and methylene chloride failed to reveal trends. Job title studies on metal degreasing and dry cleaning revealed significant MRRs (2.0 and 1.4, respectively). Publication bias was unlikely. Confounding may have remained insufficiently controlled. Unless the results are seriously biased by exposure or endpoint misclassification or by confounding, strong causal associations between CHC compounds and pancreatic cancer can be judged unlikely. Interactions between environmental and occupational agents, lifestyle factors, and genetic susceptibility remain a possibility, but the data for this meta-analysis did not address interactions.

Occupational health and safety in the least developed countries--a simple case of neglect

In many of the least developed countries, working people are significantly exposed to a number of occupational problems that may result in a deterioration of their health, safety and well being. These work-related problems are untenable, not only because of the occupational problems itself but also because of the simultaneous exposure to heat, dusts, noise, organo-chemicals, and biological and environmental pollution. This situation has existed for a long time due to various socio economic,geographical, cultural and local factors. The deteriorating situation of health and safety in the workplace may perhaps exist due to the inadequate resource facilities, economic constraints and lack of opportunity to conduct research and studies on the assessment of exposure-diseases associations. Officials, who are employed by the state, are not able to implement work regulations and labour legislation easily. Generally, they are not professionally trained and expert in the occupational health, industrial hygiene and/or safety fields, and thus, successful application and implementation of control measures are lacking. Steps to control work exposure limits have been ineffective, since national policies have been rare, owing to the multiple obstacles in preventing occupational problems. However, the major focus is on practical solutions to differing workers' needs, consideration of which is very important, depending on the what the industrial entrepreneurs could reasonably to be expected to afford. Why there is a lack of motivation and effort regarding the development of health and safety-this paper explores some important issues, aiming to focus public attention on the legacy of national and international efforts. Examples are likewise given to show the real situation of health and safety in the least developed countries.

Cancer risk in laboratory workers: an emphasis on biological research

BACKGROUND

At the end of the 1980s, several cancer clusters were observed in biological research laboratories. Over time, biological research and the technologies used have been diverse and have involved a wide range of mutagenic or carcinogenic chemical, physical and biological agents.

METHODS

We reviewed 45 published studies on cancer risk among biological research personnel and workers in closely related fields, and numerous reports based on routinely collected data.

RESULTS

Biological research could be associated with an elevated risk for pancreatic cancer, brain tumors, and certain hemopathies. A common limitation of available studies was low statistical power and the absence or inaccuracy of data on individual past exposure.

CONCLUSIONS

Overall, this study suggests a low overall risk of cancer, albeit a higher risk may be suggested for cancers of the pancreas (risk ratios ranging from 0.5 to 6.3) and brain (0.7-9.4), and for non-Hodgkin's lymphoma (0.6-51.5). We suggest ways in which multiple past exposures could be assessed more precisely and emphasize a pressing need to take into account known confounders.