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Biomedical subjects

H Welinder

Publications and source records attributed to H Welinder.

At least 37 records · Page 2Linked to original sources
PubMed1997

Anaphylactic bronchoconstriction in immunized guinea pigs provoked by inhalation and intravenous administration of hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride.

We established a guinea-pig model of anaphylactic bronchoconstriction provoked in immunized animals by inhalation and intravenous administration of 4,4-methyltetrahydrophthalic anhydride (MTHPA) and hexahydrophthalic anhydride (HHPA). Guinea pigs were immunized intradermally with either MTHPA (n = 8) or HHPA (n = 8) suspended in olive oil. Control animals (n = 8) were injected with olive oil alone. After 4 weeks, the animals were challenged during mechanical ventilation by inhalation or intravenous administration of MTHPA or HHPA conjugated with guinea-pig serum albumin (GPSA). Airway flow, and airway and esophageal pressures were measured. Resistance (R) and static compliance (Cst) of the respiratory system (rs), lung (1), and chest wall were studied with the flow-interruption technique. After challenge with MTHPA-GPSA or HHPA-GPSA, R,rs and R,1 increased dramatically while Cst,rs and Cst,1 decreased, and severe arterial hypoxia developed. The reaction occurred at a well-defined dose of anhydride and lasted about 30 min. When the same dose was repeated after 30 min, the response was much attenuated. MTHPA and HHPA can induce asthma in guinea pigs. The dose-response curve at antigen challenge is steep. Once a threshold dose is reached, a severe reaction occurs. The reactivity is then exhausted. This model may be suitable for assessing occupational asthma caused by acid anhydrides and possibly by other low-molecular-weight chemicals.

Administration, Inhalation↗
PubMed1997

Metachromatic cells and eosinophils in the nasal mucosa and N,N-dimethylbenzylamine exposure.

Six healthy non-atopic male volunteers participated in a dose-response study of N,N-dimethylbenzylamine (DMBA), which is a reactive chemical used in epoxy systems. The effects on the nasal mucosa after inhalation of 0, 20, 45, 80 and 120 microg/m3 were studied by means of symptom recordings, acoustic rhinometry, nasal lavages and nasal cytology processed for light microscopy of metachromatic cells (MC) and eosinophils (EOS). Although only minor symptoms were provoked, the numbers of MC and Eos tended to increase in a dose-response fashion after inhalation of the chemical. No signs of degranulation of the cells were found, as the levels of tryptase and eosinophil cationic protein in the nasal lavages remained low at all DMBA exposure levels. We therefore conclude that a reactive chemical such as DMBA can influence MC and Eos in the nasal mucosa even at low dose levels without causing significant clinical symptoms.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1996

Survival in cohorts of asbestos cement workers and controls.

OBJECTIVES: To measure the impact on survival of being exposed to asbestos cement dust. METHODS: Survival of 866 asbestos cement workers and 755 controls was studied with Cox's proportional hazards regression models with age as the basic time variable. The effect of cumulative exposure up to the age of 40 was investigated in an internal analysis of 635 asbestos cement workers who had dose estimates. RESULTS: The death risk was higher for the asbestos cement workers than for the controls with a hazard ratio (HR) of 1.15 (95% confidence interval was 1.00 to 1.31). The increased risk found seemed to be confined to the period 20-40 years from start of employment. The estimates of the cohort effect were almost unaffected by adjustment for smoking habits. The estimates of the exposure effect rose with increasing dose (< 4 fibre-years/ml (f-y/ml): HR = 1.00, 4-9.9 f-y/ml: HR = 1.06, > or = 10 f-y/ml: HR = 1.35, for workers with at least five years of employment), and were higher when restricted only to deaths from malignant or non-malignant respiratory disease. However, none of the point estimates were significantly increased. Median age at death was two years lower in the high than in the low, exposure group. CONCLUSIONS: The results indicate that even a moderate asbestos exposure may shorten the median duration of life in an exposed population. Compared with the estimated effect on duration of life from ever being a smoker, that of ever being an asbestos cement worker was less, although that of having a high exposure was similar.

Adult↗
PubMed1996

Biomarkers of exposure, antibodies, and respiratory symptoms in workers heating polyurethane glue.

OBJECTIVES: The pathogenic basis of respiratory disorders associated with isocyanates are still obscure. One reason for this is the lack of good estimates of human exposure. In this study exposure was estimated by measurement of isocyanate metabolites in biological samples. METHODS: In a factory using isocyanate based polyurethane (PUR) glue, isocyanate concentrations in air were measured by liquid chromatography. Samples from 174 employees were analysed for metabolites of 4,4'-methylene diphenyl diisocyanate (MDI) in plasma (P-MDX) and urine (U-MDX). After hydrolysis, 4,4'-methylenedianiline was measured by gas chromatography-mass spectrometry (GC-MS). The employees were screened for work related respiratory symptoms and tested for specific immunoglobulin E (IgE) and IgG antibodies directed against isocyanate conjugated to human serum albumin. RESULTS: The time weighted isocyanate concentrations in air were low (MDI < 0.2-7; hexamethylene diisocyanate (HDI) < 0.1-0.7; 2,6-toluene diisocyanate (TDI) < 0.1 microgram/m3). All subjects had detectable P-MDX and U-MDX. There were significant associations between the estimates of exposure to thermal degradation products of an MDI based glue and P-MDX (range < or = 0.10-5.5 micrograms/l); and U-MDX (< or = 0.04-5.0 micrograms/g creatinine); in cases of heavy exposure. P-MDX and U-MDX were associated with each other (r = 0.64; P = 0.0001), work related symptoms (P-MDX: P = 0.03; Mann-Whitney U test), and serum concentrations of MDI specific IgG antibodies (r = 0.26; P = 0.0007). Unexpectedly, high P-MDX and U-MDX concentrations were also encountered in workers cutting textile (P-MDX 2.4-4.5 micrograms/l; U-MDX 0.81-3.8 micrograms/g creatinine); the reason is still unknown. Equally unexpected, there were significant negative associations between P-MDX and liver function tests. CONCLUSIONS: The results clearly show the value of biomarkers for isocyanate exposure; in particular, P-MDX is useful. Further, these results show the risk connected with thermal degradation of PUR.

Adhesives↗
PubMed1995

Structure-activity relationships of organic acid anhydrides as antigens in an animal model.

Relationships between chemical structure and immunogenicity have been studied in 13 dicarboxylic acid anhydrides. Guinea-pigs were immunized intradermally by a single dose of 0.3 M solutions of succinic anhydride (SA), maleic anhydride (MA), methylmaleic anhydride (MMA), cis-cyclohexane-1,2-dicarboxylic anhydride (cis-HHPA), trans-cyclohexane-1,2-dicarboxylic anhydride (trans-HHPA), 4-methylcyclohexane-1,2-dicarboxylic anhydride (MHHPA), cis-1,2,3,6-tetrahydrophthalic anhydride (THPA1236), cis-3,4,5,6-tetrahydrophthalic anhydride (THPA3456), cis-3-methylcyclohex-4-ene-1,2-dicarboxylic anhydride (MTHPA34), cis-4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride (MTHPA44), phthalic anhydride (PA), 4-methylphthalic anhydride (MPA), and trimellitic anhydride (TMA) in olive oil. Specific IgE, IgG, IgG1, and IgG2 antibodies against guinea-pig serum albumin conjugates of the anhydrides were determined by passive cutaneous anaphylaxis (PCA) tests and enzyme-linked immunoabsorbant assay (ELISA). Specific IgG was significantly increased in all animals, except those immunized with THPA3456 and SA, which sensitized only 3/9 and 7/9 animals, respectively. Furthermore, the specific IgG values were very low in the SA group. The titers of specific IgG1 and IgG2 were increased in the IgG-positive animals. Specific IgE was positive in all animals immunized with MA, MHHPA, MTHPA (both isomers), and MPA, and in 6/9 and 5/9 guinea pigs immunized with TMA and MMA, respectively. The IgE titers were generally very low; PCA was negative after dilutions to 1:32, or less. The results indicate a considerable variation in the sensitizing potential between different organic acid anhydrides. The most marked general effect of the chemical structure on immunogenicity was the enhancement of antibody formation when a hydrogen atom in the anhydride was substituted with a methyl group.

Anhydrides↗
PubMed1995

Radiological changes in asbestos cement workers.

OBJECTIVE: To explore associations between exposure to asbestos cement dust and radiographic findings in lung parenchyma and pleura. METHODS: Radiographs from 174 blue collar workers and 29 white collar workers from an asbestos cement plant formed one part of the study. Progression of small opacities was further studied in those 124 blue collar workers, for whom two radiographs taken after the end of employment were available. The median readings from five readers who used the full ILO 1980 classification were used. As exposure indices, time since start of employment, duration of employment, cumulative exposure, and average intensity of asbestos exposure were used. The influence of age and smoking was also considered in multiple logistic regression analyses. RESULTS: Small opacities (profusion > or = 1/0) were closely correlated with time related exposure variables, and showed weaker association with intensity based exposure variables. The odds ratio (OR) for small opacities was equal to 2.8 (90% CI 1.2, 6.7) in the > 30 f(fibre)-y/ml group, compared with those in the 0-10 f-y/ml group. Progression of at least two minor ILO categories after the end of employment was seen in 20%. Also, pleural thickening was closely related to time. By contrast, costophrenic angle obliterations were not associated with the time related variables, but closely associated with the intensity of asbestos exposure, and tended to occur during employment. The OR was 4.5 (90% CI 1.3, 15) in the > 2 f/ml group, compared with those in the 0-1 f/ml group. CONCLUSIONS: In these workers, exposed mainly to chrysotile but also to small amounts of amphibole, the risk of radiographically visible parenchymal abnormality was substantially increased and strongly dependent on time related exposure variables. Progression was found long after the end of exposure. The findings on costophrenic angle obliterations, supposed to be sequelae of benign pleural effusions, were consistent with an immediate reaction triggered by intense asbestos exposure.

Adult↗
PubMed1995

Cancer incidence in Swedish sterilant workers exposed to ethylene oxide.

OBJECTIVES: To assess the risk of cancer, especially leukaemia, in a cohort of sterilant workers exposed to ethylene oxide (EtO). METHODS: A cohort of 2170 workers employed for at least one year in two plants that produce disposable medical equipment sterilised with EtO has previously been established. The results of an update with four more years of observation are presented. The cancer incidence was assessed for the periods 1976 to 1990 and 1972 to 1990 and cause specific standardised incidence ratios (SIRs) were calculated. Individual cumulative exposure to EtO, expressed as ppm-years, was estimated and used in exposure-response analyses. RESULTS: Six lymphohaematopoietic tumours were observed (SIR 1.78, 95% confidence interval (95% CI) 0.65-3.88), of which two were leukaemias (SIR 2.44; 95% CI 0.30-8.81). When those with cumulative exposures to EtO below the median value (0.13 ppm-years) were excluded, and a minimum of 10 years induction latency period was applied, the incidence ratio for leukaemia increased further (SIR 7.14, 95% CI 0.87-25.8), but was still not significantly enhanced. CONCLUSIONS: The risk estimate for leukaemia increased, but non-significantly, with time since start of exposure, and with cumulative exposures to EtO above the median value. The subjects with leukaemia had, however, only slightly higher cumulative exposure estimates for EtO than the average cohort member. Nevertheless, the present results may add some minor evidence for an association between EtO and an increased risk of leukaemia.

Cohort Studies↗
PubMed1994

Generation of hexahydrophthalic anhydride atmospheres in a controlled human-use test chamber.

A method for generating controlled atmospheres of hexahydrophthalic anhydride (HHPA) in an 8 m3 exposure chamber was developed. The permeation principle was used for gaseous HHPA generation. HHPA concentration was monitored by sampling on XAD-2 tubes and by a Fourier-transform infrared (FTIR) spectrometer using the partial least-square quantitative method. The repeatability of the FTIR was 5%, the reproducibility 12%, and the limit of detection 10 micrograms/m3. A bubbler method determined the sum of HHPA and HHP acid by using gas chromatography/mass spectrometry detection after derivatization with methanol/boron trifluoride. The precision of the work-up procedure was 3% and the recovery was 94% at 300 ng sampled amount of HHPA. The limit of detection was 10 ng HHPA. The variation in the permeation rate was 3% over 3 days. Different concentrations in the exposure chamber were generated by changing the temperature of the permeation tubes. The generated HHPA concentration range, at human exposure, was 3-90 micrograms/m3. The concentration at one temperature was reproducible even after major changes in the temperature. The coefficient of variation (CV) of six samples from different places in the breathing zone was 3%. The variation in the concentration, during an 8-hour human exposure at 10 micrograms/m3, was 3%. Time-weighted averages (8 hour) for human exposures of 10 micrograms/m3 (CV = 15%; n = 6); 37 micrograms/m3 (CV = 5%; n = 5); and 81 micrograms/m3 (CV = 6%; n = 9) were obtained at intended concentrations of 10 micrograms/m3, 40 micrograms/m3, and 80 micrograms/m3. The loss of HHPA in the exposure chamber was 54% (CV = 17%).(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1994

Nasal challenge shows pathogenetic relevance of specific IgE serum antibodies for nasal symptoms caused by hexahydrophthalic anhydride.

Hexahydrophthalic anhydride (HHPA) is a component of some epoxy resin systems. A high fraction of HHPA-exposed workers display nasal symptoms, and some of them have specific serum antibodies. To test the pathogenetic relevance of the antibodies nasal challenge tests were performed with a conjugate of HHPA and human serum albumin (HSA) at three increasing concentrations. Eleven subjects, who were IgE-sensitized against HHPA (positive in RAST and in skin-prick test against the HHPA-HSA conjugate), and who reported work-related nasal symptoms, had a significant increase of nasal symptoms and a decrease of nasal inspiratory peak flow after the challenges. The symptoms were associated with specific serum IgE, but with IgG. Further, significant increases were found in eosinophil and neutrophil counts, and in levels of tryptase, and albumin, whereas no clear rise was recorded for eosinophil cationic protein in nasal lavage fluid. Nine subjects, who were not sensitized, but who complained of work-related nasal symptoms, and 11 subjects, who were not sensitized and had no symptoms, displayed no significant change in any of these parameters. It is concluded that the symptoms in some of the workers were caused by an IgE-mediated mast cell degranulation, followed by an inflammatory reaction, engaging eosinophil and neutrophil cells.

Adult↗
PubMed1994

Symptoms and immunologic markers induced by exposure to methyltetrahydrophthalic anhydride.

A study was performed in 43 workers exposed to methyltetrahydrophthalic anhydride (MTHPA) used as a hardener in an epoxy resin system. Ten workers sensitized to MTHPA (group SS; presence of serum IgE antibodies against a conjugate of MTHPA and human serum albumin (HSA) detected by RAST) had significantly higher levels of tryptase in nasal lavage fluid than 19 nonsensitized workers with work-related nasal symptoms (group NS) and 14 nonsensitized workers without nasal symptoms (group NN). This suggests an ongoing mast-cell-mediated reaction in the sensitized group. No statistically significant differences were found in the three groups concerning eosinophil cationic protein (ECP) and TAME-activity in lavage fluid. However, there was a significant increase in serum ECP in the SS group, as compared with a group of unexposed controls. Nasal challenge with MTHPA-HSA, performed in a subsequent study in seven workers from the SS group, six from the NS group, and seven from the NN, caused a larger increase of symptom score and a more pronounced decrease in nasal inspiratory peak flow in the SS group than in the other two groups. No significant rise was recorded for tryptase and ECP in lavage fluid in any of the three groups after challenge. The combined results of the two studies indicate that specific IgE antibodies play a pathogenetic role in at least some of the cases of work-related nasal symptoms associated with MTHPA exposure.

Blood Proteins↗
PubMed1994

Retention patterns of asbestos fibres in lung tissue among asbestos cement workers.

Retention patterns in lung tissue (determined by transmission electron microscopy and energy dispersive spectrometry) of chrysotile, tremolite, and crocidolite fibres were analysed in 69 dead asbestos cement workers and 96 referents. There was an accumulation of tremolite with time of employment. Among workers who died within three years of the end of exposure, the 13 with high tremolite concentrations had a significantly longer duration of exposure than seven in a low to intermediate category (medians 32 v 20 years; p = 0.018, one sided). Crocidolite showed similar patterns of accumulation. In workers who died more than three years after the end of exposure, there were no correlations between concentrations of amphibole fibres and time between the end of exposure and death. Chrysotile concentrations among workers who died shortly after the end of exposure were higher than among the referents (median difference in concentrations 13 million fibres (f)/g dry weight; p = 0.033, one sided). No quantitative differences in exposure (duration or intensity) could be shown between workers with high and low to intermediate concentrations. Interestingly, all seven workers who had had a high intensity at the end of exposure (> 2.5 f/ml), had low to intermediate chrysotile concentrations at death, whereas those with low exposure were evenly distributed (31 subjects in both concentration categories); hence, there was a dependence between last intensity of exposure and chrysotile concentration (p = 0.014). Among 14 workers with a high average intensity of exposure, both those (n = 5) with high tissue concentrations of chrysotile and those (n = 10) with high tissue concentrations of tremolite fibres had more pronounced fibrosis than those with low to intermediate concentrations (median fibrosis grades for chrysotile: 2 v 1, p = 0.021; for tremolite: 2 v 0.5, p = 0.012). Additionally, workers who died shortly after the end of exposure with high concentrations of chrysotile and crocidolite had smoked more than those with low intermediate concentrations (medians for chrysotile 35 v 15 pack-years, p = 0.030; for crocidolite 37 v 15 pack-years, p = 0.012). The present data indicate that chrysotile has a relatively rapid turnover in human lungs, whereas the amphiboles, tremolite and crocidolite, have a slower turnover. Further, chrysotile retention may be dependent on dose rate. Chrysotile and crocidolite deposition and retention may be increased by tobacco smoking; chrysotile and tremolite by fibrosis.

Aged↗
PubMed1994

Acute respiratory disorder, rhinoconjunctivitis and fever associated with the pyrolysis of polyurethane derived from diphenylmethane diisocyanate.

OBJECTIVES: A case is described of complex reactions associated with exposure to diphenylmethane diisocyanate (MDI), with some immunologic observations. METHODS: Medical history, clinical examinations, and analyses of immunologic parameters and the 4,4'-MDI-related amine 4,4'-diaminodiphenylmethane (MDA) in hydrolyzed serum and urine were used. RESULTS: The patient, a mechanic whose medical history suggested repeated attacks of a work-related pulmonary or systemic disease, was examined because of acute respiratory disorder, rhinoconjunctivitis, and a late systemic reaction after exposure to polyurethane pyrolysis products, including 4,4'-MDI (air level 15 micrograms.m3). Spirometry showed a partly reversible obstructive dysfunction, and a skin-prick test was positive versus isocyanates conjugated with human serum albumin (HSA). MDA was detected in hydrolyzed serum (5.6 ng.ml) and urine (1.6 micrograms.g creatinine-1). In serum, there were specific immunoglobulin (Ig) G (IgG1 and IgG4) and IgE antibodies to 4,4'-MDI-HSA and other isocyanates (phenylisocyanate, toluene diisocyanate, p-toluene monoisocyanate, hexamethylene diisocyanate) conjugated with HSA, a very high total IgE, a raised total IgG, and moderate neutrophilia and eosinophilia. The specific antibodies declined, but were still increased five years later. Furthermore, the values of circulating immune complexes were high. In vitro, the circulating immune complexes in serum increased after the addition of 4,4'-MDI-HSA. The patient had anti-Clq antibodies, which probably accounted for part of the circulating immune complexes. CONCLUSIONS: The reactions associated with MDI exposure (in combination with exposure to pyrolysis products) had features compatible with immediate hypersensitivity and with a complement-mediated immune-complex reaction.

Allergens↗
PubMed1993

Small airways function in aluminium and stainless steel welders.

The effect of welding fumes on small airways was studied in 25 male subjects who welded in aluminium (Al) and to some extent also in stainless steel (SS). Despite a low exposure to welding fumes as compared to the permissible exposure limits, excretion of Al in urine was found to be increased in all subjects (median value: 0.29 mmol/mol creatinine on Friday afternoon, as compared to an upper reference level of 0.10 mmol/mol creatinine). In addition, the welders displayed increased prevalences of work-related eye and airways (pharyngitis and non-specific bronchial hyperreactivity) symptoms, as compared to 25 matched controls. Short-term welders (< or = 2.5 years) had more symptoms related to the upper airways than did long-term welders, which may indicate a selection. Spirometry, closing volume and volume of trapped gas (VTG) did not deviate. However, after methacholine inhalation, the long-term welders had a significantly steeper slope of the alveolar plateau on the single-breath nitrogen wash-out test, and a slight increase in VTG, as compared to the short-term welders and the controls. These findings may indicate a welding fume-induced increase in the reactivity of the small airways. Because Al welding was far more frequent than SS welding, an association with the former seems likely.

Adult↗
PubMed1993

Occupational exposure to hexahydrophthalic anhydride: air analysis, percutaneous absorption, and biological monitoring.

Urinary hexahydrophthalic acid (HHP acid) levels were determined in 20 workers occupationally exposed to hexahydrophthalic anhydride (HHPA) air levels of 11-220 micrograms/m3. The levels of HHP acid in urine increased rapidly during exposure and the decreases were also rapid after the end of exposure. The elimination half-time of HHP acid was 5 h, which was significantly longer than in experimentally exposed volunteers, possibly indicating distribution to more than one compartment. There was a close correlation between time-weighted average levels of HHPA in air and creatinine-adjusted levels of HHP acid in urine collected during the last 4 h of exposure (r = 0.90), indicating that determination of urinary HHP acid levels is suitable as a method for biological monitoring of HHPA exposure. An air level of 100 micrograms/m3 corresponded to a postshift urinary HHP acid level of ca. 900 nmol/mmol creatinine in subjects performing light work for 8 h. Percutaneous absorption of HHPA was studied by application of HHPA in petrolatum to the back skin of three volunteers. The excreted amounts of HHP acid in urine, as a fraction of the totally applied amount of HHPA, were within intervals of 1.4%-4.5%, 0.2%-1.3%, and 0%-0.4% respectively, indicating that the contribution from percutaneous absorption is of minor importance in a method for biological monitoring.

Adult↗
PubMed1993

Incidence of cancer and exposure to toluene diisocyanate and methylene diphenyldiisocyanate: a cohort based case-referent study in the polyurethane foam manufacturing industry.

OBJECTIVE: To assess the association between occupational exposure to toluene diisocyanate or methylene diphenyldiisocyanate and risk of cancer. DESIGN: A cohort based case-referent study. STUDY BASE: 7023 subjects employed during the period 1958 to 1987 in nine Swedish polyurethane foam manufacturing plants. MAIN OUTCOME MEASURES: Odds ratios adjusted with respect to the matching factors (age at risk, calendar year at risk, sex, and plant), calculated from the conditional logistic regression model. RESULTS: A non-significant association was found between high exposure to isocyanates and prostate cancer (OR 2.66, 90% confidence interval (90% CI) 0.39-18.1), which was not enhanced when an induction latency period of 10 years was applied. An association between isocyanate exposure and colon cancer was even weaker. No associations were seen for non-Hodgkin's lymphoma and rectal cancer. CONCLUSIONS: The tentative associations, derived from a previous cohort study, between isocyanate exposure and excess risk for non-Hodgkin's lymphoma and rectal cancer were not supported. Instead, non-significant associations with prostate cancer, and possibly colon cancer, were seen.

Case-Control Studies↗
PubMed1993

Mortality and cancer morbidity among cement workers.

OBJECTIVE: To explore associations between exposure to cement dust and cause specific mortality and tumour morbidity, especially gastrointestinal tumours. DESIGN: A retrospective cohort study. SUBJECTS AND SETTING: 2400 men, employed for at least 12 months in two Swedish cement factories. MAIN OUTCOME MEASURES: Cause specific morality from death certificates (1952-86). Cancer morbidity from tumour registry information (1958-86). Standardised mortality rates (SMRs; national reference rates) and standardised morbidity incidence rates (SIRs; regional reference rates) were calculated. RESULTS: An increased risk of colorectal cancer was found > or = 15 years since the start of employment (SIR 1.6, 95% confidence interval (95% CI) 1.1-2.3), mainly due to an increased risk for tumours in the right part of the colon (SIR 2.7, 95% CI 1.4-4.8), but not in the left part (SIR 1.0, 95% CI 0.3-2.5). There was a numerical increase of rectal cancer (SIR 1.5, 95% CI 0.8-2.5). Exposure (duration of blue collar employment)-response relations were found for right sided colon cancer. After > or = 25 years of cement work, the risk was fourfold (SIR 4.3, 95% CI 1.7-8.9). There was no excess of stomach cancer or respiratory cancer. Neither total mortality nor cause specific mortality were significantly increased. CONCLUSIONS: Diverging risk patterns for tumours with different localisations within the large bowel were found in the morbidity study. Long term exposure to cement dust was a risk factor for right sided colon cancer. The mortality study did not show this risk.

Cause of Death↗
PubMed1993

Cancer incidence and mortality in the Swedish polyurethane foam manufacturing industry.

Toluene diisocyanate (TDI) and methylene diphenyldiisocyanate (MDI) are used in large quantities in the polyurethane foam manufacturing industry. Both substances are mutagenic and at least TDI is carcinogenic to animals, but the occupational hazard with respect to cancer is not known. Cancer incidence and mortality patterns were therefore investigated in a cohort of 4154 workers from nine Swedish plants manufacturing polyurethane foam, employed for at least one year. Each workplace and job task in the nine plants was categorically assessed for each calendar year by an experienced occupational hygienist, for "no exposure", "low or intermittent exposure", or "apparent exposure" to TDI and MDI. The observed deficit for all cause mortality (standardised mortality ratio (SMR) 0.78, (95% confidence interval (95% CI) 0.66-0.93) became smaller (SMR 0.92) excluding the first 10 years since the start of exposure and was ascribed to a healthy worker effect. No increased risk for death from bronchial obstructive diseases was found. An almost statistically significant deficit occurred for all malignant neoplasms (standardised incidence ratio (SIR) 0.81, 95% CI 0.63-1.02); slight (not significant) increased risks were found for rectal cancer (SIR 1.66) and non-Hodgkin's lymphoma (SIR 1.53). The SIR for non-Hodgkin's lymphoma increased to 2.80 (95% CI 0.76-7.16) when the first 10 years since first exposure were excluded from the observation period. The corresponding figure for rectal cancer was 1.92 (95% CI 0.52-4.92). Further restricting the analysis to those who had experienced an apparent exposure to TDI or MDI increased the SIR for both rectal cancer (3.19, 95% CI 0.66-9.33), and non-Hodgkin's lymphoma (3.03, 95% CI 0.37-10.9). These estimates were based, however, on few incident cases. As the cohort is still young and little time has elapsed since the start of exposure, future follow ups will enable a more conclusive evaluation.

Adult↗