The history of pulp and paper bleaching: respiratory-health effects.
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Biomedical subjects
Publications and source records attributed to K Torén.
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Two cases of contact allergy to methylisothiazolinones from slimicides used in pulp and paper mills are described. The first patient worked as a batcher in a paper mill, and he was in charge of pumping slimicides containing methylisothiazolinones. During pumping, the liquid often overflowed, and his clothes were wet daily with slimicides. After 3 months of work, he began to suffer from dermatitis, which improved when he was away from work. A clinical investigation confirmed the dermatitis diagnosis and a positive skin patch test to Kathon CG was found. The second patient worked as an agent for a firm marketing slimicides containing methylisothiazolinones. One of his tasks was to pump slimicides into the mills, and during such operations his clothes often got wet from slimicides. After some years of work, he began to suffer from erythema and dermatitis after contact with the slimicides. A skin patch test showed a strongly positive reaction to Kathon CG. These case reports draw the attention to the fact that employees in the pulp and paper industry handling slimicides are exposed to extraordinarily high concentrations of methylisothiazolinones and run a substantial risk of being sensitized. The report also stresses the need for improved handling routines of those strong sensitizers in the paper mills.
The objective of the present study was to investigate mortality attributable to asthma in different occupations. The mortality from asthma among Swedish workers between 1981 and 1992 was investigated by a linkage between official mortality statistics and the occupational information in the 1980 National Census. For each occupation, a smoking-adjusted standardized mortality ratio (SMR) was calculated. The information about smoking habits was obtained from smoking surveys carried out from 1977 to 1979. Only occupations with more than five cases were considered in the analysis. Significantly increased mortality from asthma was found among male farmers (smoking-adjusted SMR = 146; 95% confidence interval [CI] 105-187) and male professional drivers (smoking-adjusted SMR = 144, 95% CI = 101-209) and female hairdressers (smoking-adjusted SMR = 332, 95% CI = 102-525). The increased mortality among three occupational groups (hairdressers, farmers, and professional drivers) out of 46 groups analyzed may be random occurrences. However, farmers and hairdressers are exposed to agents causing asthma, indicating that the increased mortality may be attributable to occupational exposure.
The aim of this study was to investigate the reactivity of the nasal mucosa of patients with pollen allergy compared to healthy controls, when challenged with histamine outside the pollen season. Assessments were made with symptom score, acoustic rhinometry, nasal peak expiratory and inspiratory flow (NPEF and NPIF) and rhinomanometry in order to find the most sensitive method for the purpose. Twenty-one patients with seasonal allergic rhinitis and 20 healthy controls were challenged with histamine dihydrochloride in increasing concentrations (0.01, 0.1, 1.0 mg/ml) locally in the nose. Our results show no difference in mucosal reactivity between the patients and controls regardless of the method used. When comparing the methods we find that NPIF and NPEF are more sensitive to mucosal changes than the other methods we have studied.
Workers in the pulp and paper industry are exposed to different substances, such as hydrogen sulfide and other reduced sulfur compounds, chlorine, chlorine dioxide, sulfur dioxide, terpenes, and paper dust. The exposure level depends on the process, i.e., sulfite, sulfate, groundwood, bleachery, or paper production. Hitherto, exposures have been poorly described and more studies are certainly needed. Workers with repeated exposure peaks to chlorine, e.g., bleachery workers, seem to have an impaired lung function and an increased prevalence of respiratory symptoms. Exposure to high levels of paper dust, (> 5 mg/m3) causes impaired lung function. Therefore, exposure to respiratory irritants is an important, and probably overlooked, occupational risk among certain groups of pulp and paper workers. Some studies indicate that sulfate workers with high exposure to reduced sulfur compounds have an increased mortality due to ischemic heart disease. However, before any definite conclusions can be drawn, the impact of important confounders, such as shift-work and smoking habits have to be further evaluated.
This paper reviews the available literature regarding the work environment in pulp and paper mills and the risk for malignant diseases. An increased risk for lung cancer among pulp and paper mill workers has been reported. Most studies are inconclusive with regard to considerations of etiologic agents. However, maintenance workers seem to be at an increased risk for lung cancer, as well as for malignant mesothelioma, indicating that this occupational group was (is) exposed to asbestos. Workers exposed to chlorine compounds also seem to run an increased risk for lung cancer. An increased risk for malignant lymphomas among pulp mill workers is a constant finding. The increased risk is observed both among sulfite and sulfate workers, indicating a common exposure. Such an exposure could be wood dust, terpenes, or preservatives present in the wood. An increased risk for leukemias has been found in many studies carried out on pulp and paper workers, but the studies do not permit any conclusions about etiologic factors. In some studies an increased risk for stomach cancer has been found. However, the socioeconomic status of the workers is strongly related to stomach cancer, and factors, such as dietary habits, have not been taken into account in any of the reviewed studies. Hence, no further conclusions can be drawn regarding etiologic agents.
BACKGROUND: Knowledge of the mortality outcome of asthma is limited to hospital case series follow-up. METHODS: To provide estimates of the mortality and cause of death in patients with asthma comparison of observed and expected number of deaths in patients with asthma for the observation period 1962-1986 was made. The study group was 262 patients aged 19-81 years with severe asthma. The group was a total sample of patients with a daily treatment of oral steroids more than one year, 1962-1963, from the city of Göteborg. RESULTS: Mortality from all causes was significantly raised among the asthmatics (179 deaths versus 83.5 expected, relative risk (RR) - 2.1, 95% confidence interval (CI) : 1.8-2.5). There was an excess mortality from ischaemic heart disease 58 versus 29.9 deaths (RR = 1.9, 95% CI : 1.4-2.4), especially among women (RR = 2.4, 95% CI : 1.7-2.2). However, there was also an increased mortality from asthma (39 versus 0.4 deaths) and chronic obstructive pulmonary disease (11 versus 0.5 deaths). CONCLUSIONS: These findings suggest that subjects with severe asthma, especially women, have an increased mortality from ischaemic heart disease. The results may reflect confounding, mainly smoking and physical inactivity. Other explanations may be side effects of the antiasthmatic drugs or an effect of longstanding airway obstruction.
OBJECTIVES: To estimate the annual rates of self reported occupational asthma in different occupational groups in Sweden. METHODS: All claims of occupational asthma 1990-2 in the Swedish register of reported occupational diseases were classified according to occupation. The number of people employed in each occupational group in the general population was obtained from the 1990 national census. Reporting rates (cases/million/ year) were calculated for each occupation with more than five reported cases, according to sex and age (20 to 64 years, and 20 to 44 years). RESULTS: 1010 cases were reported giving an annual crude reporting rate of 80/million (95% confidence interval (95% CI) 70 to 90). For men, the crude reporting rate was 91/million (95% CI 84 to 98), and for women 70/million (95% CI 80 to 106). The highest reporting rates were among male bakers-(775/million), furnacemen (702/million), male welders (647/million), female chemical and plastic production workers (629/million), and female poultry and dairy farm workers (602/million). CONCLUSIONS: A surveillance system based on self reporting is influenced by considerable bias, especially reporting bias. However, results for the specific occupations with high rates were similar to those found with other surveillance systems. This indicates that our system is a useful one.
OBJECTIVES: The purpose of this study was to investigate nasal symptoms and function among workers exposed to lime dust and to determine if a reconstruction of the workplace improved the worker's nasal health. METHODS: In 1992, pulp-mill workers (N = 15) exposed to lime dust and an equal number of matched unexposed referents were examined by questionnaires, nasal peak expiratory flow, the saccharin test, nasal lavage, and a clinical examination of the upper airways. The study was repeated one year later, after the pulp mill had been rebuilt. Dust levels were measured on both occasions with stationary and personal samplings. RESULTS: In 1992 the total dust level was 1.2 mg.m-3. The saccharin test showed a significantly increased nasal transit time for the exposed workers in comparison with that of the unexposed referents (difference 3.5 min, 95% confidence interval 0.1-6.9 min). One year later the dust levels had decreased to 0.1 mg. m-3, and the difference in nasal transit time had decreased (difference- 0.8 min, 95% confidence interval -4.8-3.3 min). CONCLUSIONS: Workers exposed to lime dust have an impaired mucociliary function. This impairment is probably due to the alkalinity of the lime. When dust levels are reduced, mucociliary function improves; therefore renovating a workplace to reduce dust levels has a positive effect.
BACKGROUND: Workers using vibrating tools have an increased prevalence of vibration-induced white fingers. One example of such workers is autopsy assistants, who use vibration for skull sawing. CASE HISTORY: A previously healthy 42-year-old Swedish male smoker had worked as an autopsy assistant at a forensic department between 1977 and 1991. He prepared corpses for autopsy, including sawing the skulls with an electric saw. Beginning in 1983, his right index finger blanched in cold. During subsequent years the blanching spread to the other fingers on the right hand, except for the thumb. The findings in the physical examination and the results of blood tests were normal. Digital blood pressure after cooling showed a severe vasospastic reaction in both middle fingers. Vibration measurements during skull sawing showed a frequency-weighted acceleration level of 8.9 m.s-2. QUESTIONNAIRE SURVEY: A questionnaire was mailed to all assistants (N = 17) preparing autopsies and to all medical examiners, as referents (N = 18), at the Swedish Institutes of Forensic Medicine. It was answered by 13 assistants (76%), 1 woman and 12 men, and 16 medical examiners (89%), 3 women and 13 men. Eleven of the assistants (85%), including one woman, and one of the physicians (6%), a men, reported a history of blanching fingers provoked by chill (difference 79%, P = 0.00003, Fisher's exact test). CONCLUSIONS: Autopsy assistants at forensic departments seem to have an increased prevalence of self-reported blanching fingers, which may be an effect of exposure to high levels of vibration.
The aim of this study was to estimate to what degree malignant pleural mesotheliomas were reported as occupational cancers. The study included all malignant pleural mesotheliomas (n = 210) found in the Cancer Registry 1980-1989 from four Swedish counties. Whether or not a case was reported as occupational cancer was found in the Swedish Register of Reported Occupational Diseases. To evaluate the presence of exposure histories, the chest department files for 58 mesotheliomas from one county were reviewed. The reporting was low, with only 75 mesotheliomas (36%) reported. All the cases were men, and for the men, the reporting frequency was 42%. The reporting was significantly lower for the last part of the decade than for the first part. The reporting frequency decreased with age. In the review of the chest department files, an exposure history was found in 93% of the reported cases and in 47% of the unreported cases. It is concluded that physicians must give more priority to exposure histories in patients with pleural mesotheliomas.
The aim of the present cohort study was to investigate whether exposure to paper dust causes increased risk for respiratory symptoms or asthma. The cohort included all workers at a soft paper mill who had worked there for more than 1 year 1960-1986 (n = 1,697). Randomly selected inhabitants of the mill town (n = 781) were used as unexposed referents. Both groups were investigated using a postal questionnaire. From the paper mill cohort, workers with high cumulative exposure (n = 313), with medium cumulative exposure (n = 321), and with low cumulative exposure (n = 338) to paper dust were selected. In the 1960s and 1970s, the dust levels were between 5 and 10 mg/m3. After adjustment for smoking and gender, paper dust exposure resulted in elevated prevalence ratios for chronic cough, chronic phlegm, wheeze, and breathlessness. The prevalence ratios ranged from 1.3 to 2.5. No significantly increased risk of asthma was found among the exposed, incidence rate ratio 1.4 (95% confidence interval 0.93-1.8). Among the exposed, there was an insignificantly increasing incidence rate ratio, 1.0, 1.4, 2.1, with increasing cumulative exposure. In conclusion, an increased risk for respiratory symptoms was observed among workers exposed to paper dust, but the study does not permit any definite conclusions regarding asthma and paper dust exposure.
Process and office workers at a Swedish paper mill (n = 274) and dairy workers (n = 45) were investigated with questionnaires regarding skin symptoms. In the second part of the study, subjects reporting skin symptoms and a random sample of subjects without symptoms were examined and investigated with patch testing. Pruritus and skin irritation probably related to exposure to dust were found. The results do not indicate an increased prevalence of contact allergy. In two cases, positive patch test reactions to paper size (rosin) and a slimicide, mercaptobenzothiazole (MBT), were noted.
The first widely used questionnaire in respiratory epidemiology was the questionnaire from the Medical Research Council (MRC) of Great Britain. In the first version, from 1960, there were only a few questions about wheezing, but in later editions, more questions about asthma and asthma-like symptoms were added. The MRC questionnaire initiated the development of other questionnaires such as the European Community for Coal and Steel (ECSC) questionnaire of respiratory symptoms and the questionnaire from the American Thoracic Society and the Division of Lung Diseases (ATS-DLD-78). In Tucson, Ariz, a questionnaire was developed in the 1970s that was focused on the subject's own report of asthma. In Great Britain, a questionnaire was developed in the 1980s with the intention of finding the most valid symptom-based items for identifying asthma, "the IUATLD (1984) questionnaire." When judging the validity of a questionnaire, it is essential to understand sensitivity and specificity. Sensitivity is the fraction of the truly diseased subjects found to be diseased using the questionnaire. Specificity is the fraction of the truly healthy subjects found to be healthy using the questionnaire. Regarding questionnaires dealing with asthma, the situation is confusing because of the absence of any gold standard for asthma. The most usual mode of validation has been to test the questionnaire against the results of a clinical physiologic investigation, often a nonspecific bronchial challenge test. Another approach has been to compare the answers from the questionnaire with the clinical diagnoses of asthma. When validated in relation to bronchial challenge tests, the questions about self-reported asthma have a mean sensitivity of 36 percent (range, 7 to 80 percent) and a mean specificity of 94 percent (range, 74 to 100 percent). The questions about "physician-diagnosed asthma" have even higher specificity, 99 percent. When validated in relation to a clinical diagnosis of asthma, the mean sensitivity for the question about self-reported asthma was 68 percent in the reviewed studies (range, 48 to 100 percent). The specificity was 94 percent (range, 78 to 100 percent). One problem in using the presence of bronchial hyperreactivity (BHR) as a gold standard for asthma is that many people with BHR report no respiratory complaints. In other words, the presence of BHR is a measure with high sensitivity but low specificity for asthma. The effect of using a methacholine challenge test as a standard for the disease will thus be an underestimation of the sensitivity of the questionnaire.(ABSTRACT TRUNCATED AT 400 WORDS)
We wanted to assess the quantitative importance of asbestos as a cause of lung cancer. In a case-referent study, the exposure to asbestos, tobacco smoke and some other occupational exposures were compared between 147 cases of lung cancer (100 men, 47 women), 111 hospital referents, and 109 population referents, all below the age of 75 yrs and living in an industrial city. The attributable risk of lung cancer due to asbestos exposure was 16% in men (95% confidence interval 1-31%). No woman had occupational exposure to asbestos. We conclude that in the mid 1980's tobacco smoking was the major attributable risk, being 95% for men and 78% for women, but that in men asbestos was an appreciable contributing factor in the general population of a Swedish industrial city.
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