Cancer morbidity and quartz exposure in Swedish iron foundries.

PURPOSE: The aim of this study was to determine cancer morbidity amongst Swedish iron foundry workers with special reference to quartz exposure. In addition to respirable dust and quartz, phenol, formaldehyde, furfuryl alcohols, polycyclic aromatic hydrocarbons (PAHs), carbon black, isocyanates and asbestos are used or generated by foundry production techniques and exposure to any of these substances could have potentially carcinogenic effects. METHODS: Cancer morbidity between 1958 and 2004 was evaluated in a cohort of 3,045 male foundry workers employed for >1 year between 1913 and 2005. Standardised incidence ratios (SIRs) with 95 % confidence intervals (95 % CI) were determined by comparing observed numbers of incident cancers with frequencies in the Swedish cancer register. Exposure measures were assessed using information from the personal files of employees and modelling quartz measurement based on a database of 1,667 quartz measurements. Dose responses for lung cancer were determined for duration of employment and cumulative quartz exposure for latency periods >20 years. RESULTS: Overall cancer morbidity was not increased amongst the foundry workers (SIR 1.00; 95 % CI, 0.90-1.11), but the incidence of lung cancer was significantly elevated (SIR 1.61; 95 % CI, 1.20-2.12). A non-significant negative dose response was determined using external comparison with a latency period of >20 years (SIR 2.05, 1.72 1.26 for the low, medium and high exposure groups), supported by internal comparison data (hazard ratios 1, 1.01, 0.78) for the corresponding groups. For cancers at sites with at least five observed cases and a SIR > 1.25, non-significant risks with SIRs > 1.5 were determined for cancers of the liver, larynx, testis, connective muscle tissue, multiple myeloma plasmacytoma and lymphatic leukaemia. CONCLUSIONS: A significant overall risk of lung cancer was determined, but using external and internal comparison groups could not confirm any dose response at our cumulative quartz dose levels.

Exposure assessment and modeling of quartz in Swedish iron foundries for a nested case-control study on lung cancer.

Exposure assessment of quartz in Swedish iron foundries was performed based on historical and current measurement data. To evaluate the exposure-response relationship between quartz exposure and lung cancer, we modeled quartz exposure from our database of measurements using determinants job title, time period, and company. Based on these modeled exposure data, we conducted a nested case-control evaluation. In our database, the overall individual, daily time-weighted average (TWA) quartz concentrations of current and historical data varied between 0.0018 and 4.9 mg/m(3), averaging 0.083 mg/m(3). Job titles with mean TWAs for the whole study period exceeding the European Union recommended occupational exposure limit of 0.05 mg/m(3) were fettlers (0.087 mg/m(3)), furnace and ladle repair (0.42 mg/m(3)), and maintenance (0.054 mg/m(3)) workers. The mixed model analysis demonstrated significant determinants on the job level for furnace and ladle repair (ß = 4.06; 95% confidence interval [CI] 2.78-5.93). For all jobs, significantly higher exposure levels occurred only during the first time period, 1968-1979 (ß = 2.08; 95% CI 1.75-2.47), and a decreasing but not significant trend was noted for the three following 10-year time periods up to 2006 (ß = 1.0, 0.96 and 1, respectively). Two iron foundries had significantly higher quartz concentration levels than the others (ß = 1.31; 95% CI 1.00-1.71 and ß = 1.63; 95% CI 1.00-2.65, respectively). The individual cumulative quartz exposure measures were categorized in low, medium, and high exposure (0.5-<1, 1-1.9 and ≥ 2 mg/m(3)*years, respectively). In the nested case-control analysis, we found the highest odds ratios of lung cancer (OR 1.17; 95% CI 0.53-2.55) for the medium exposure group. No dose-response trend or significantly increased risk was determined for our high exposed group (≥2 mg/m(3)), representing 40 years of exposure at >0.05 mg/m(3) of quartz. To conclude, certain foundry workers are still exposed to high levels of quartz, but an increased risk of lung cancer caused by quartz exposure in these Swedish iron foundries could not be confirmed at our exposure levels.

Inflammatory markers and exposure to occupational air pollutants.

OBJECTIVES: To study the possible relationship between inhalation of airborne particles in the work environment and inflammatory markers in blood. METHODS: Total dust was sampled in the breathing zone of 73 subjects working with welding, cutting, grinding and in foundries such as iron, aluminium, and concrete. Stationary measurements were used to study different size fractions of particles including respirable dust, particulate matter (PM)(10) and PM(2.5), the particle number concentration, the number of particles deposited in the alveoli, and total particle surface area concentration. Inflammatory markers such as interleukin-6 (IL-6), C-reactive protein (CRP), fibrinogen, d-dimer, and urate were measured in plasma or serum before the first shift after the summer vacation and after the first, second, and fourth shift. RESULTS: The mean level of total dust in the breathing zone was 0.93 mg/m(3). The proxies for mean respirable dust fraction was 0.27 mg/m(3), PM(10) 0.60 mg/m(3), and PM(2.5) was 0.31 mg/m(3). The IL-6 values increased by 50% after the first day, but decreased after shift on the second and fourth day. CRP did not increase after the first shift but increased by 17% after the second shift. Other biomarkers were unaffected. A multiple linear regression analysis of a subgroup of 47 subjects showed a statistically significant positive relationship between particle exposure and post-shift IL-6. CONCLUSION: This study supports previous investigations observing increases of IL-6 at air concentrations of PM(10) or PM(2.5) between 0.13 and 0.3 mg/m(3) among healthy subjects. This increase of IL-6 may indicate an increased risk of coronary heart disease.

Nephrotoxicity of uranium in drinking water from private drilled wells.

OBJECTIVES: To investigate the association between uranium in drinking water from drilled wells and aspects of kidney function measured by sensitive urine tests. METHODS: Three hundred and one of 398 eligible subjects (75.6%) aged 18-74 years with daily drinking water supplies from private drilled wells located in uranium-rich bedrock (exposed group) volunteered to participate along with 153 of 271 local controls (56.4%) who used municipal water. Participants responded to a questionnaire on their water consumption and general health, and provided a morning urine sample and drinking water for analysis. RESULTS: The uranium content of well water samples (n=153) varied considerably (range <0.20-470 microg/l, median 6.7 microg/l, 5% >100 microg/l), while uranium levels in all samples of municipal water (n=14) were below the limit of quantification (0.2 microg/l). Urinary levels of uranium were more than eight times higher in exposed subjects than in controls (geometric means 38 and 4.3 ng/l, respectively; p<0.001), but their mean urine lead levels were not significantly different. There was a strong curvilinear correlation between uranium in drinking water and in urine (r2=0.66). Levels of albumin, beta(2)-microglobulin, protein HC as well as kappa and lambda immunoglobulin chains in urine from exposed and controls were similar. The N-acetyl-beta-d-glucosaminidase (NAG) activity was significantly lower in the exposed group vs. controls, possibly secondary to differential storage duration of samples from the two groups. Even in regression models adjusting for gender, age and smoking no association of uranium in water and the kidney function parameters was observed. Using uranium in urine in the entire study group as a marker of exposure, however, a tendency of exposure-related increases of beta(2)-microglobulin, protein HC and kappa chains were noted. This tendency was enhanced after exclusion of subjects with diabetes mellitus from the analysis. CONCLUSIONS: Uranium levels in urine were strongly correlated to levels in drinking water from drilled wells. There were no clear signs of nephrotoxicity from uranium in drinking water at levels recorded in this study, but some indications of an effect were observed using uranium in urine as a measure of overall uranium exposure. The clinical relevance of these findings remains unclear.

Quartz and dust exposure in Swedish iron foundries.

Exposure to respirable quartz continues to be a major concern in the Swedish iron foundry industry. Recommendations for reducing the European occupational exposure limit (EU-OEL) to 0.05 mg/m3 and the corresponding ACGIH(R) threshold limit value (ACGIH-TLV) to 0.025 mg/m3 prompted this exposure survey. Occupational exposure to respirable dust and respirable quartz were determined in 11 Swedish iron foundries, representing different sizes of industrial operation and different manufacturing techniques. In total, 436 respirable dust and 435 respirable quartz exposure measurements associated with all job titles were carried out and are presented as time-weighted averages. Our sampling strategy enabled us to evaluate the use of respirators in certain jobs, thus determining actual exposure. In addition, measurements using real-time dust monitors were made for high exposure jobs. For respirable quartz, 23% of all the measurements exceeded the EU-OEL, and 56% exceeded the ACGIH-TLV. The overall geometric mean (GM) for the quartz levels was 0.028 mg/m3, ranging from 0.003 to 2.1 mg/m3. Fettler and furnace and ladle repair operatives were exposed to the highest levels of both respirable dust (GM = 0.69 and 1.2 mg/m3; range 0.076-31 and 0.25-9.3 mg/m3 and respirable quartz (GM = 0.041 and 0.052 mg/m3; range 0.004-2.1 and 0.0098-0.83 mg/m3. Fettlers often used respirators and their actual quartz exposure was lower (range 0.003-0.21 mg/m3, but in some cases it still exceeded the Swedish OEL (0.1 mg/m3. For furnace and ladle repair operatives, the actual quartz exposure did not exceed the OEL (range 0.003-0.08 mg/m3, but most respirators provided insufficient protection, i.e., factors less than 200. In summary, measurements in Swedish iron foundries revealed high exposures to respirable quartz, in particular for fettlers and furnace and ladle repair workers. The suggested EU-OEL and the ACGIH-TLV were exceeded in, respectively, 23% and 56% of all measurements regardless of the type of foundry. Further work on elimination techniques to reduce quartz concentrations, along with control of personal protection equipment, is essential.

Silicone sealers, acetic acid vapours and dental erosion: a work-related risk?

The aim of the present study was to investigate whether the acetic acid released by some silicone sealers during the curing process poses an increased risk for dental erosion, thus constituting an occupational hazard to exposed individuals. The material comprised 13 individuals (x=30 years, 10 men and 3 women) who had been exposed to an average of 4.2 years' (range 0.6-10 years) of working with silicone. Each had comprehensive medical and dental examinations carried out. A sex- and aged-matched group of 20 healthy, unexposed workers from the same company served as controls for the medical examination, while study models from randomly selected sex- and age-matched individuals were used as controls for assessing the severity of erosion. Using a questionnaire, an assessment of the role of various possible factors related to oral and general health, and to dental erosion in particular, was made for each participant in the exposed group. Clinical examination included recordings of severity of dental erosion, presence of "cuppings", DMFT, salivary secretion rate and buffer capacity, visible plaque index and gingival bleeding index. In addition, bitewing radiographs, study casts and intraoral colour transparencies were obtained for each individual. The severity of dental erosion was significantly higher in those exposed to silicone compared to controls. There was also a significant correlation between the period of exposure to silicone in the workplace and severity of erosion. Medical problems, especially with regard to upper respiratory tract symptoms, were significantly more common among exposed individuals than controls. In conclusion, a relationship between occupational exposure to acetic acid vapours from silicone sealers and development of dental erosion would appear to exist.

Prevention of allergy to acrylates and latex in dental personnel.

Contact allergy to acrylate monomers and immediate hypersensitivity to latex gloves in dental personnel calls for preventive measures to reduce the risks. The aim of the study was to evaluate the preventive effect of an information campaign after a 3-year follow-up. The campaign included instructions and training according to an ordinance, both in writing and orally, e.g. concerning the choice of products and protection devices and the proper handling of the materials. The follow-up was carried out through 1997-2000 and included all eligible 513 subjects. Information on new cases was ascertained by a questionnaire and reports from the occupational health service and the department of dermatology. The number of expected new cases was based on the incidence rate, derived from a preceding prevalence study in the same county, and the exposed years at risk in the follow-up period. No new case of allergy to acrylates or latex rubber was found in the follow-up period as against 4.91 expected (p = 0.007). In conclusion, this study indicates that occupational allergies can be prevented successfully, but requires vigorous measures to influence the behaviour and the routines of daily work in dental practice.

Exposure to nitrous oxide in delivery suites at six Swedish hospitals.

OBJECTIVE: This study presents occupational peak and average exposures to nitrous oxide in delivery suites in six Swedish hospitals and evaluates different scavenging techniques. METHODS: Exposure measurements based on four consecutive 2-h samples (n = 111) were used to calculate 8-h time-weighted averages (8-h TWAs) for 36 midwives and assistant midwives. Short-term (15 min) samples to study peak exposure were also included in the monitoring program. Diffusive samplers were used for monitoring, and analyzed by thermal desorption and gas chromatography-mass spectrometry (GC-MS). The effect on exposure of different types of scavenging systems was studied by mixed model analysis. RESULTS: The 8-h TWA (n = 36) nitrous oxide concentrations varied between 2.5 and 260 mg/m3, and the geometric means for all the 8-h TWAs was 17 mg/m3 for the midwives and 42 mg/m3 for the assistant midwives. Around 25% of all the 8-h TWAs exceeded the American Conference of Industrial Hygienists' (ACGIH) threshold limit value (TLV-TWA) of 90 mg/m3 (50 ppm). For the short-term samples (n = 29) the nitrous oxide levels varied between 19 and 4,200 mg/m3, and 14% exceeded the Swedish occupational exposure ceiling limit value of 900 mg/m3. The 8-h TWAs were four times higher when the non-ventilated and ventilated simple masks were compared to the double mask (P = 0.02). This trend, although not statistically significant, was also seen for the short-term samples. CONCLUSION: A diffusive sampling method and a GC-MS analytical technique was used for long- and short-term sampling of nitrous oxide. A large number of TWAs exceeded the ACGIH-TLV. Mask connected to scavenging systems significantly reduced the exposures. Furthermore, using a forced general air ventilation system in addition to improved work and delivery routines for the staff and the mother-to-be substantially improved the air quality in the delivery suites.

On the use of different measures of exposure-experiences from a case-control study on testicular cancer and PVC exposure.

Associations between exposure to PVC plastics and testicular cancer have been reported. To improve the exposure-response analysis in a matched case-control study on testicular cancer and occupational exposures, a self-administered exposure questionnaire and expert assessment was applied and different exposure measures were developed. The questionnaires regarding work histories and employment in PVC production, manufacturing, and handling of PVC products were completed by 1582 subjects (90%). By expert assessment, 360 subjects were considered exposed, and the exposure intensity to PVC plastics for different working periods was determined. Different exposure measures to PVC plastics were then developed, such as ever/never exposed, duration, maximum intensity, median intensity, and cumulative median intensity. The correlation between the different measures of exposure was high for exposure duration and the cumulative median exposure intensity (Spearman rank coefficient r(s) = 0.94), as was the correlation between the maximum intensity and the median intensity (r(s) = 0.94). The agreement between the answers in the questionnaire and the expert assessments was moderate, Kappa value 0.56. The odds ratio for "ever" exposed based on the exposure as reported in the questionnaire was 1.1 (95%, CI 0.82-1.56), and as determined by expert assessment 1.3 (CI 1.05-1.69). The odds ratios for all four different categories of exposure measures varied between 0.86 and 2.6 but decreased by increasing exposure. An overall excess of testicular cancer for the PVC exposed vs. the unexposed was not supported by the pattern seen in a standard exposure-response analysis based on several exposure measures. The findings stress the importance of using several exposure measures as dose surrogates when the underlying toxic mechanisms are unknown and when there are indications of an overall effect.

Airways symptoms, immunological response and exposure in powder painting.

OBJECTIVES: Powder painting is an alternative to solvent-based spray painting. Powder paints may contain organic acid anhydrides (OAAs), which are irritants to the airways and may cause sensitisation. The aim of this study was to determine the prevalence of respiratory symptoms and immunological response among powder painters and to describe the exposure to OAAs. METHODS: In all, 205 subjects in 32 enterprises participated: 93 exposed and 26 formerly exposed workers in 25 powder paint shops and 86 unexposed workers. They completed a questionnaire about working conditions and symptoms and took part in a medical examination, which included a lung function test. Urine samples, for determination of two OAAs, and blood samples, for analysis of specific antibodies against the OAAs, were taken. In addition, 33 paint samples were analysed for nine OAAs. RESULTS: The powder painters reported more work-related respiratory symptoms than unexposed subjects did. The prevalence of three or more symptoms was 24% in subjects with low exposure, 44% in highly exposed individuals, 46% in formerly exposed subjects and 19% in unexposed workers. Asthma symptoms were frequent, 7%, 40%, 15% and 2%, respectively. Regression analyses of the lung volumes did not show any influence of exposure. IgG, but not IgE, against the OAAs and metabolites of OAAs was found in some subjects, but no associations with the exposure could be observed. OAAs were found in only small amounts in the paint samples. CONCLUSIONS: The exposure to organic acid anhydrides was estimated to be low, and yet, IgG antibodies to OAA were observed in some subjects. The prevalence of work-related symptoms from the eyes and the airways was relatively high among the powder painters, and these symptoms, but not the lung volumes, were clearly related to exposure. The symptoms were probably caused by irritative properties of the powder paint dust.

Primary prevention of cardiovascular disease by an occupational health service.

BACKGROUND: Worksites are considered to be a key channel for the delivery of interventions to prevent cardiovascular disease. The aim of this study was to evaluate the effect on the blood cholesterol levels of an intervention program offered by an occupational health service. METHODS: The intervention group consisted of 95 employees and the reference group consisted of 74 employees, in all, 169 subjects, with a serum cholesterol > or = 5.2 mmol/l. Both groups completed a standardized questionnaire. Occupational health nurses carried out the blood sampling before and after the program. The intervention group was then offered counseling on physical activity and a dietician offered individual counseling on healthy food habits. The reference group was not the subject of the intervention program. RESULTS: The mean cholesterol level decreased by 0.3 mmol/l (5%) in the intervention group and for the men the decrease was 0.5 mmol/l, while the mean level of the reference group was unchanged. Furthermore, there was a nonsignificant decrease of the mean triglyceride level in the intervention group. CONCLUSION: The results of this controlled trial indicates that risk factors for cardiovascular disease can be reduced by interventions at the worksite. Even modest reductions of cholesterol levels may reduce the risk to a tangible degree.

Testicular cancer and occupational exposure to polyvinyl chloride plastics: a case-control study.

Exposure to polyvinyl chloride (PVC) plastics as a risk factor for testicular cancer was investigated. In total, 981 cases who were 20-75 years old and had reported to the Swedish Cancer Registry during 1993-1997 were included. One matched control from the population registry was used. Exposure was assessed by a questionnaire that was supplemented over the phone. Furthermore, an occupational hygienist qualified all exposures. In all, 791 matched pairs completed the questionnaire. Overall exposure to PVC plastics gave the odds ratio (OR)=1.35, 95% confidence interval (CI)=1.06-1.71, increasing with >10 year latency period to OR=1.45, 95% CI=1.06-1.98. No dose-response relationships were found but rather an inverse relationship with the highest odds ratios in the lowest exposure category. In conclusion, no clear association with testicular cancer and exposure to PVC could be found in our study in contrast to a previous observation.