Testicular cancer among Swedish pulp and paper workers

BACKGROUND: The incidence of testicular cancer has increased in recent decades. The aims of the present study were to elucidate whether Swedish paper and pulp mill workers had an increased incidence of testicular cancer, and to investigate whether certain occupational groups within the pulp and paper mill workforce were at increased risk. METHODS: The study was based on the Swedish Cancer Environment Register, which links the incidence of cancer for the period 1971-1990 with 1960 and 1970 National Census data on specific industries and occupations for all employed subjects in Sweden. RESULTS: Among maintenance workers employed both in 1960 and in 1970 in paper mills there was an increased risk for testicular cancer (standardized incidence ratio (SIR) 7.4, 95% confidence intervals (CI) 1.5-22), especially for seminomas (SIR 10.1, 95% CI 2.1-29). Maintenance workers were also at increased risk when analyzing workers employed in 1960, 1970, or both years. CONCLUSIONS: This study indicates an increased risk for testicular cancer, especially seminomas, among maintenance workers, but not among process workers, in Swedish paper mills.     

Cancer incidence among Swedish pulp and paper mill workers: a cohort study of sulphate and sulphite mills

Purpose

Associations between various malignancies and work in the pulp and paper industry have been reported but mostly in analyses of mortality rather than incidence. We aimed to study cancer incidence by main mill pulping process, department and gender in a Swedish cohort of pulp and paper mill workers.

Methods

The cohort (18,113 males and 2,292 females, enrolled from 1939 to 1999 with >1 year of employment) was followed up for cancer incidence from 1958 to 2001. Information on the workers’ department and employment was obtained from the mills’ personnel files, and standardized incidence ratios (SIRs) were calculated using the Swedish population as reference.

Results

Overall cancer incidence, in total 2,488 cases, was not increased by work in any department. However, risks of pleural mesothelioma were increased among males employed in sulphate pulping (SIR, 8.38; 95 % CI, 3.37–17) and maintenance (SIR, 6.35; 95 % CI, 3.47–11), with no corresponding increase of lung cancer. Testicular cancer risks were increased among males employed in sulphate pulping (SIR, 4.14; 95 % CI, 1.99–7.61) and sulphite pulping (SIR, 2.59; 95 % CI, 0.95–5.64). Female paper production workers showed increased risk of skin tumours other than malignant melanoma (SIR, 2.92; 95 % CI, 1.18–6.02).

Conclusions

Incidence of pleural mesothelioma was increased in the cohort, showing that asbestos exposure still has severe health consequences, and highlighting the exigency of strict asbestos regulations and elimination. Testicular cancer was increased among pulping department workers. Shift work and endocrine disruptors could be of interest in this context.     

Cancer incidence of workers in the Finnish pulp and paper industry

The cancer incidence of 3,545 workers in the Finnish pulp and paper industry was assessed in a retrospective cohort study. The cohort included workers with continuous employment of at least one year between 1 January 1945 and 31 December 1961 and was followed until 31 December 1980. Six subcohorts were formed (sulfite mill, sulfate mill, paper mill, board mill, maintenance department, and power plant). Separate analyses were made for the 2,597 workers hired after 1 January 1945. The smoking habits were surveyed. Among the men, 196 cases of primary cancer were detected versus 203.8 expected [standardized incidence ratio (SIR) 96, 95% confidence interval (95% CI) 82-114], and there were 47 cancer cases among the women versus 57.9 expected (SIR 91, 95% CI 60-108). Lung cancer occurred in 78 men (62.6 expected, SIR 125, 95% CI 98-155), and the excess was the most prominent for the male board mill workers (40 observed, 81.1 expected, SIR 222, 95% CI 158-302), particularly after 20 year's latency (25 observed, 7.8 expected, SIR 323, 95% CI 209-476). Analogous excesses of lung cancer occurred among the men (especially the male board mill workers) who began work after 1 January 1945. The findings were not explained by smoking habits.     

Cohort mortality study of Swedish pulp and paper mill workers-nonmalignant diseases

OBJECTIVES: The aim of this study was to determine mortality among pulp and paper mill workers according to the main mill pulping process, department, and gender, particular reference being given to diseases of the circulatory and respiratory systems. METHODS: The cohort of 18 163 men and 2 291 women employed between 1939 and 1999 and with >1 year of employment was followed for mortality from 1952 to 2001 (acute myocardial infarction from 1969). Standardized mortality ratios (SMR) with 95% confidence intervals (95% CI) were estimated by comparing the observed number of deaths with the expected number for the entire Swedish population. Exposure was assessed from personnel files in the mills. Data from an exposure measurement database are also presented. RESULTS: There were 5898 deaths in the cohort. Total mortality had an SMR of 1.02 (95% CI 0.98-1.06) for the men in the sulfate mills and an SMR of 0.93 (95% CI 0.90-0.97) for the men in the sulfite mills. Mortality from acute myocardial infarction was increased among the men in both the sulfate and sulfite mills [SMR 1.22 (95% CI 1.12-1.32) and SMR 1.11 (95% CI 1.02-1.21), respectively] and by department in sulfate pulping (SMR 1.29, 95% CI 1.07-1.54), paper production (SMR 1.26, 95% CI 1.06-1.49), and maintenance (SMR 1.16, 95% CI 1.02-1.30). Mortality from cerebrovascular disease, diabetes mellitus, and nonmalignant respiratory diseases was not increased. CONCLUSIONS: Death from acute myocardial infarction, but not cerebrovascular diseases, was increased in this cohort and was probably related to a combination of different occupational exposures (eg, dust, sulfur compounds, shift work, and noise).     

Cohort study of cancer risk among male and female shift workers

OBJECTIVES: Melatonin, a hormone that inhibits experimentally induced cancers, is suppressed by nighttime exposure to light so that nighttime shift workers may be at an increased risk of cancer. Previous studies of shift workers found an increased risk of breast cancer among women and suggested a possible increased risk of colon cancer among women and prostate cancer. The present study was conducted to see whether these previous findings could be confirmed and whether shift workers are at elevated risk for cancer at additional sites. METHODS: Altogether 2 102 126 male and 1 148 661 female workers were identified who worked in both 1960 and 1970. Their jobs were classified according to the percentage of shift workers, and they were followed from 1971 through 1989 or until they were diagnosed with cancer or died. Standardized incidence ratios (SIR) were used to compare the adjusted cancer incidence rates for shift workers with those for nonshift workers. RESULTS: Cancer rates were not elevated for the male shift workers [all sites combined: N=6524 cases among shift workers, SIR 1.02, 95% confidence interval (95% CI) 1.00-1.05; prostate: N=1319, SIR 1.04, 95% CI 0.99-1.10] or for the female shift workers (all sites combined: N=268, SIR 1.00, 95% CI 0.89-1.13; breast: N=70 cases, SIR 0.94, 95% CI 0.74-1.18). CONCLUSIONS: No evidence was found for an association between shift work and breast or prostate cancer, or all cancer sites combined among shift workers.     

Risk of cancer among paper recycling workers.

OBJECTIVES: Studies in traditional paper mills have indicated an excess cancer risk, and mutagenic compounds have been identified in the industry. No studies have reported on risk of cancer in paper recycling. Therefore the cancer incidence in Danish paper recycling mills was investigated. METHODS: 5377 employees in five paper recycling plants were included in a historical cohort study. The workers had been employed in paper recycling in 1965-90, and the cohort was followed up until 31 December 1993. The expected number of cancer cases was calculated from national rates. RESULTS: There was significantly more pharyngeal cancer among male workers (seven observed (standardised incidence ratio (SIR) 3.33, 95% confidence interval (95% CI) 1.34 to 6.87)). There was slightly more lung cancer among male workers in production (39 observed, SIR 1.21, 95% CI 0.86 to 1.65). Risk of Hodgkin's disease was doubled in male production worker (four observed, SIR 1.90, 95% CI 0.51 to 4.85). CONCLUSIONS: The increased risk of pharyngeal cancer found in this study is interesting but may be influenced by confounders such as smoking and alcohol intake. This study also indicates an excess risk of Hodgkin's disease, which is in accordance with some studies in the traditional paper mills. As this is the first report on risk of cancer in paper recycling, further studies are needed.     

Cancer incidence in a cohort of Swedish sewage workers: extended follow up

OBJECTIVES: To study the cancer incidence in a cohort of Swedish sewage workers. An increased incidence of cancer of the stomach, the kidney and the nervous system in this cohort was previously reported. This new analysis reports on 9 more years of follow up. METHODS: The study is an analysis of a cohort of all 711 employees at 17 Swedish sewage plants employed for at least for 1 year during the years 1965-86. Assessment of exposures was performed by classification of work tasks. Standardised incidence ratios (SIRs), and 95% confidence intervals (95% CIs) were calculated. RESULTS: The total cancer incidence was not significantly increased (SIR = 1.2, 95% CI 0.92 to 1.5) but the incidence of prostate cancer was (SIR = 1.6, 95% CI 1.0 to 2.5), and based on two cases only, there seemed to be a significant increase of cancer of the nose and the nasal sinuses (SIR = 12, 95% CI 1.5 to 44). The incidence of stomach cancer was also increased (SIR = 2.3, 95% CI 0.99 to 4.5). There was no relation between cancer incidence and level of sewage exposure. CONCLUSIONS: Sewage workers did not have an increased risk of cancer, and the increased risk estimates for some specific cancer sites were not conclusive.       

Lung cancer and mesothelioma in the pleura and peritoneum among Swedish insulation workers

OBJECTIVES: To estimate the risk of cancer and death in Swedish insulation workers some years after their exposure to asbestos had stopped. One hypothesis was that the risk of lung cancer would tend to decrease some years after the exposure had ended. METHODS: In a cohort study the cancer morbidity and cause of death was investigated in 248 insulation workers and compared with the corresponding morbidity and mortality in the general population. Due to stringent regulations, exposure to asbestos of all types had almost ended in Sweden in the mid- 1970s. Through a questionnaire, surviving insulation workers were asked about their exposure to asbestos and their smoking habits. RESULTS: Between 1970 and 1994 there were 86 deaths compared with the 46.0 expected (standardised incidence ratio (SIR) 1.9; 95% confidence interval (95% CI) 1.5 to 2.3), the increase was mainly due to an increased cancer mortality. The morbidity was increased for lung cancer (11 cases v 2.5 expected (SIR 4.4; 95% CI 2.2 to 7.9)), peritoneal mesothelioma (seven cases; no expected incidence could be calculated as the occurrence is too rare in the general population), cancer in pancreas (five cases v 0.7 expected (SIR 7.1; 95% CI 2.3 to 16.7)). No cases of pleural mesothelioma were found. The risk of lung cancer did not tend to approach that of the general population after the exposure to asbestos decreased. CONCLUSIONS: In the 1980s and the early 1990s, Swedish insulation workers still have a highly increased risk of diseases related to asbestos. The attributable risk for death and cancer was about 50%. The study also confirms the previous finding that mesothelioma in insulation workers seems to be situated in the peritoneum more often than in the pleura.     

Mortality and cancer incidence in Swedish battery workers exposed to cadmium and nickel

OBJECTIVE: To follow up cancer incidence and mortality in a group of Swedish battery workers exposed to nickel hydroxide and cadmium oxide. METHODS: 869 workers, employed at least one year between the years 1940 and 1980 were followed up until 1992. Vital status and causes of death were obtained from the Swedish cause of death registry. Cancer morbidity was retrieved from the Swedish cancer registry. Regional reference rates were used to compute the expected numbers of deaths and cancers. RESULTS: Up to 31 December, 1992, a total of 315 deaths (292 in men and 23 in women) had occurred in the cohort. For men, the overall standardised mortality ratio (SMR) was 106 (95% confidence interval (95% CI) 93.7 to 118) and for women 83.8 (95% CI 53.1 to 126). The SMRs for total cancer mortality were 125 (95% CI 98.2 to 157) for men and 69.5 (95% CI 25.5 to 151) for women. The SMR for lung cancer in men was 176 (95% CI 101 to 287). No lung cancers were found among female workers. Up to 31 December, 1991, a total of 118 cancers had occurred in the cohort. A significantly increased standardised incidence ratio (SIR) was found for cancer of the nose and nasal sinuses in men, three cases v 0.36 expected, yielding an SIR of 832 (95% CI 172 to 2430). Applying a 10 year latency period in cohort members exposed to > or = 1000 micrograms cadmium/m3, the SIR was 1107 (95% CI 134 to 4000). Similarly, for cohort members exposed to 2000 micrograms nickel/m3, the SIR was 1080 (95% CI 131 to 3900). CONCLUSION: There was an increased overall risk for lung cancer, but no exposure-response relation between cumulative exposure to cadmium or nickel and risk of lung cancer. There was a highly significant increased risk of cancer of the nose and nasal sinuses, which may be caused by exposure to nickel or cadmium or a combination of both exposures.

 

     

Occupation and smoking adjusted mortality due to asthma among Swedish men.

The study aims to survey the mortality from asthma in different occupations among Swedish men. The design was a register based cohort study where the smoking adjusted mortality due to asthma among Swedish men 1971-80 was investigated. For each occupation a smoking adjusted standardised mortality ratio (SMR) was calculated based on a linkage between official mortality statistics 1971-80 and occupational information in the 1970 national census. The information about the smoking habits among different occupations was obtained from a smoking survey carried out in 1963. In the statistical analysis only occupations with more than 10 deaths were considered. A significantly increased mortality from asthma was found among farmers (smoking adjusted SMR 137, 95% confidence interval (95% CI) 115-156), farm workers (smoking adjusted SMR 170, 95% CI 107-235), woodworking machine operators (smoking adjusted SMR 226, 95% CI 108-344), clerical workers (smoking adjusted SMR 161, 95% CI 102-220), packers and labellers (smoking adjusted SMR 144, 95% CI 100-188), and watchmen (smoking adjusted SMR 212, 95% CI 104-320). Exposure to organic dust, such as fresh wood dust and dusts in the farming environment, may cause increased mortality due to asthma.     

Occupation and smoking adjusted mortality due to asthma among Swedish men

The study aims to survey the mortality from asthma in different occupations among Swedish men. The design was a register based cohort study where the smoking adjusted mortality due to asthma among Swedish men 1971-80 was investigated. For each occupation a smoking adjusted standardised mortality ratio (SMR) was calculated based on a linkage between official mortality statistics 1971-80 and occupational information in the 1970 national census. The information about the smoking habits among different occupations was obtained from a smoking survey carried out in 1963. In the statistical analysis only occupations with more than 10 deaths were considered. A significantly increased mortality from asthma was found among farmers (smoking adjusted SMR 137, 95% confidence interval (95% CI) 115-156), farm workers (smoking adjusted SMR 170, 95% CI 107-235), woodworking machine operators (smoking adjusted SMR 226, 95% CI 108-344), clerical workers (smoking adjusted SMR 161, 95% CI 102-220), packers and labellers (smoking adjusted SMR 144, 95% CI 100-188), and watchmen (smoking adjusted SMR 212, 95% CI 104-320). Exposure to organic dust, such as fresh wood dust and dusts in the farming environment, may cause increased mortality due to asthma.     

Cancer incidence and mortality in a Swedish rubber tire manufacturing plant

BACKGROUND: A classification of 12 work categories was used to evaluate the cancer incidence and mortality among a cohort of Swedish rubber tire workers. METHODS: Cancer incidence and mortality in the cohort was compared with expected values from national rates. Standardized incidence and mortality ratios were calculated for the total cohort, for sub-cohorts and with the inclusion of a latency requirement. RESULTS: Among men, increased incidence and mortality risks were found for cancer in the larynx; SIR=2.10; 95% confidence intervals (95% CI): 1.05-3.76, SMR=2.08; 95% CI: 0.42-6.09. Increased risks were also seen for cancer in the trachea, bronchus, and lung; SIR=1.62; 95% CI: 1.28-2.02, SMR=1.54; 95% CI: 1.21-1.94, the incidence risk was highest among those with the longest exposure duration and among workers in compounding/mixing, milling, and maintenance. Decreased incidence risks were seen for cancer of the prostate (SIR=0.74; 95% CI: 059-0.92) and skin (SIR=0.57; 95% CI: 0.36-0.84). CONCLUSIONS: The finding of an excess of tumors in the respiratory system is in agreement with earlier findings in other studies on rubber tire workers. The results on other cancer types are compared to earlier findings and related to work processes and chemical exposures of possible causal importance.     

Exposure to ozone gases in pulp mills and the onset of rhinitis

OBJECTIVE: Rhinitis is a common upper respiratory disease influenced by both genetic and environmental factors. It is also accepted that allergic rhinitis may precede asthma, a disease with more serious consequences. The purpose of this study was to determine whether the risk of noninfectious rhinitis is increased after accidental gassings with ozone among bleachery workers in two pulp mills. METHODS: Bleachery workers (N=120) from two Swedish pulp mills using ozone as their bleaching agent were compared with control workers (N=80) not exposed to ozone in two adjacent paper mills. All of the participants were mailed a respiratory questionnaire that included items about asthma, noninfectious rhinitis, self-reported gassings, and smoking. Hazard ratios (HR) were calculated with proportional hazards regression models. RESULTS: The bleachery workers who reported gassings from ozone were found to be at increased risk of noninfectious rhinitis [HR 3.4, 95% confidence interval (95% CI) 1.3-8.7] when compared with control workers. Bleachery workers without self-reported ozone gassings were not at increased risk (HR 0.9, 95% CI 0.3-2.4). CONCLUSION: Acute exposure to high levels of ozone increases the risk of noninfectious rhinitis. This finding supports the view that peak exposures to irritants should be prevented in pulp mills.     

Wood dust exposure and cancer incidence: a retrospective cohort study of furniture workers in Estonia

BACKGROUND: Occupational wood dust exposure is associated with increased risk of sinonasal cancer in men. However, little is known whether it is associated with sinonasal cancer in women or with malignancies of other sites. METHODS: In a retrospective cohort study of furniture workers, cancer incidence in 3723 men and 3063 women between 1968 and 1995 was compared to the incidence in the general population of Estonia. Cancer risks were analyzed by employment duration and occupation. RESULTS: The standardized incidence ratio (SIR) for all cancers did not differ significantly from one. Two men and one woman had sinonasal cancer (expected 1.07 and 0.53, respectively). Significantly increased risk of colon cancer was seen in the cohort (SIR 1.65, 95% confidence interval (CI) 1.22-2.17). Subjects employed for 10 years and over had significant excess of colon cancer (SIR 2.29, 95% CI 1.28-3.77) and rectal cancer (SIR 2.10, 95% CI 1.05-3.76) in the analysis by employment duration using exposure with a latency of 20 years. The nonsignificant excess of pharyngeal cancer in men (SIR 1.82) and lung cancer in women (SIR 1.43) was restricted to short-term workers. CONCLUSIONS: This study found an excess of colon and rectal cancer in furniture workers. There was no increase in total cancer risk.     

Cancer incidence in airline cabin crew: experience from Sweden

Aims: To determine the cancer incidence in Swedish cabin crew.

Methods: Cancer incidence of cabin crew at the Swedish Scandinavian Airline System (SAS) (2324 women and 632 men) employed from 1957 to 1994 was determined during 1961–96 from the Swedish National Cancer Register. The cancer incidence in cabin crew was compared with that of the general Swedish population by comparing observed and expected number of cases through standardised incidence ratios (SIR). A nested case-control study was performed, including cancer cases diagnosed after 1979 and four controls per case matched by gender, age, and calendar year.

Results: The SIR for cancer overall was 1.01 (95% CI 0.78 to 1.24) for women and 1.16 (95% CI 0.76 to 1.55) for men. Both men and women had an increased incidence of malignant melanoma of the skin (SIR 2.18 and 3.66 respectively) and men of non-melanoma skin cancer (SIR 4.42). Female cabin attendants had a non-significant increase of breast cancer (SIR 1.30; 95% CI 0.85 to 1.74). No clear associations were found between length of employment or cumulative block hours and cancer incidence.

Conclusions: Swedish cabin crew had an overall cancer incidence similar to that of the general population. An increased incidence of malignant melanoma and non-melanoma skin cancer may be associated with exposure to UV radiation, either at work or outside work. An increased risk of breast cancer in female cabin crew is consistent with our results and may in part be due to differences in reproductive history.

     

Cancer among women textile workers in Shanghai, China: overall incidence patterns, 1989-1998

BACKGROUND: Cancer incidence in women textile workers has not been adequately studied. The aim of this study was to examine site-specific cancer incidence patterns in a cohort of 267,400 women textile workers in Shanghai, China. METHODS: Women employed by the Shanghai Textile Industry Bureau (STIB) were followed for cancer incidence from 1989 to 1998. Age-adjusted standardized incidence ratios (SIRs) and 95% confidence intervals (CI) were computed based on Shanghai Cancer Registry (SCR) rates. RESULTS: There was a decrease in cancer incidence for the cohort compared with urban Shanghai women (SIR = 0.91, 95% CI = 0.89-0.93). There were small increased risks of other endocrine tumors (SIR = 1.31, 95% CI = 1.02-1.65). There were decreased risks for esophageal (SIR = 0.54, 95% CI = 0.44-0.66), stomach (SIR = 0.79, 95% CI = 0.73-0.85), rectal (SIR = 0.88, 95% CI = 0.78-0.98), lung (SIR = 0.80, 95% CI = 0.74-0.86), cervical (SIR = 0.37, 95% CI = 0.28-0.50), ovarian (SIR = 0.85, 95% CI = 0.75-0.96), and bladder cancers (SIR = 0.63, 95% CI = 0.46-0.85). CONCLUSIONS: Women employed in the textile industry had a lower than expected cancer experience compared with urban Shanghai women. Further research on this cohort will examine associations between site-specific cancers and occupational exposures to dusts and chemicals.     

Cancer incidence of dry cleaning,laundry and ironing workers in Sweden

OBJECTIVES: This study investigated the risk of cancer among dry cleaners, launderers, and pressers in a large record-linkage study in Sweden. METHODS: The Swedish Cancer Register III contains nationwide data on cancer incidence between 1971 and 1989, by occupation and industry of employment, as reported in the 1960 and 1970 censuses. Dry cleaners, launderers, and pressers were compared with the remaining part of the employed population using multivariable Poisson regression models and standardized incidence ratios. RESULTS: Dry cleaners, launderers, and pressers employed in the laundry, ironing, or dyeing industry in both censuses showed an increased risk of Hodgkin's disease [relative risk (RR) 2.69,95% confidence interval (95% CI) 1.01-7.19], an elevated risk of leukemia among women (RR 2.53,95% CI 1.44-4.46), and increased risks of stomach (RR 1.80,95% CI 1.05-3.11) and laryngeal (RR 2.42, 95% CI 0.91-6.45) cancers among men. The results of the analyses of launderers and dry cleaners as a separate occupational group reflected those of the whole exposure group, while pressers showed an elevated lung cancer risk (RR 1.67, 95% CI 0.75-3.72). CONCLUSIONS: If they are not due to chance or confounding, the results of this study reflect either the potentiation of other carcinogens by solvents or direct effects. The results are limited by the use of job and industry titles as proxies for occupational exposures.     

Incidence of cancer among the participants of the Finnish Asbestos Screening Campaign

OBJECTIVES: Cancer risk has been estimated for asbestos production workers or other heavily exposed asbestos workers in numerous studies. The bulk of the asbestos epidemic results come, however, from past intermittent exposures during asbestos product use. This study concentrated on estimating the risk of cancer in such a population. METHODS: Altogether 23285 men and 930 women invited to a nationwide screening campaign for benign asbestos-related diseases in 1990-1992 were followed for cancer through the Finnish Cancer Register up to 1998. Standardized incidence ratios (SIR) were calculated in comparison with the total Finnish population. RESULTS: Altogether 1392 cases of cancer were found among the men. The risk was slightly, but significantly elevated for lung cancer [SIR 1.14, 95% confidence interval (95% CI) 1.01-1.26), mesothelioma (SIR 2.77, 95% CI 1.66-4.31), and prostate cancer (SIR 1.21, 95% CI 1.09-1.34). The risk of lung cancer was slightly higher among the invited nonparticipants (SIR 1.48, 95% CI 1.20-1.79) than among the participants (SIR 1.02, 95% CI 0.88-1.17). About 98% of the lung cancers occurred in current or ex-smokers. CONCLUSIONS: In a population of long-term construction workers, the risk of lung cancer and mesothelioma was increased, but considerably lower than among insulators, asbestos sprayers, or patients with asbestosis. As it was not possible to follow most of the invited nonparticipants in the original screening study, selection bias by smoking or other life-style factors possibly correlated to the individual's decision to participate in the health screening cannot be excluded.     

Respiratory health among bleachery workers exposed to ozone and chlorine dioxide

OBJECTIVES: This study investigated the possibility of occupational exposure to ozone increasing the risk of obstructive airway disease among bleachery workers. : Bleachery workers (N = 129) from two Swedish pulp mills using ozone for bleaching were studied together with referents (N = 80) from adjacent paper mills. The pulp mills had previously used chlorine dioxide as the bleaching agent. Testings included spirometry, methacholine challenge testing, and questionnaires. Area samplings showed sporadic ozone levels exceeding 0.9 ppm. RESULTS: There was a greater prevalence of wheezing (25%) among the bleachery workers with a history of gassings (from ozone, chlorine, or sulfur dioxide) than among those without gassings (18%) and among the referents (13%). Among the current smokers the fraction with a slightly increased bronchial responsiveness to methacholine was greater among the bleachery workers reporting gassings than among those that had not been gassed. For the period from 1992 to 1996, when the mills were using ozone, there was an increased incidence rate of wheezing among the workers in the bleachery (incidence rate ratio 2.3, 95% confidence interval 1.6-5.8). CONCLUSIONS: Repeated exposure to irritants increases the risk of asthma-like symptoms. This finding reinforces the view that repeated peak exposures to irritants must be prevented in pulp mills.     

Cancer incidence among women in the Norwegian pulp and paper industry.

BACKGROUND: The aim of the present study was to investigate cancer risk among women working in the Norwegian pulp and paper industry. The cohort included a total of 4,247 workers employed for at least one year between 1920 and 1993 (108,095 person-years), 85% of them as paper or administration workers. METHODS: The follow-up period for cancer was from 1953-1993. No data of exposure measurements were available. The analyses were based on comparisons of standard incidence ratios. The expected numbers of cancer cases were calculated using the five-year age-specific incidence rates for the entire female population. RESULTS: During the follow-up period, 380 new cases of cancer were observed vs. 322 expected (SIR = 1.2, 95% CI = 1.07-1.30). An excess risk of ovarian cancer was found (SIR = 1.5, 95% CI = 1.07-2.09). The SIR was highest among those younger than 55 years, and mostly among those working in paper departments. Short-term workers showed increased risk of lung and bladder cancer. CONCLUSIONS: Based on results from the present study, the increased risk of ovarian cancer is difficult to interpret, since existing knowledge of its etiology is limited. However, these women might have been exposed to various work-related agents such as talc, microbes, and different types of paper dust.