Risk of breast cancer among Norwegian women with visual impairment

Experimental studies suggest that melatonin has a protective effect against breast cancer. Exposure to light suppresses melatonin secretion, but to a lesser degree in totally blind persons. Breast cancer was investigated in a cohort of 15 412 Norwegian visually impaired women. The risk among totally blind women was 0.64 (95% CI = 0.21-1.49, 5 cases only), and for those who became blind before age of 65, the SIR was 0.51 (95% CI = 0.11-1.49). Our findings give support to the 'melatonin hypothesis'.

Cancer incidence among workers in six Norwegian aluminum plants

OBJECTIVES

This study investigated associations between exposure to polycyclic aromatic hydrocarbons (PAH) and the incidence of lung, bladder, kidney, and pancreatic cancer among Norwegian aluminum plant workers.

METHODS

Cancer incidence was investigated from 1953 to 1996 among 11,103 men employed for more than 3 years in the industry, giving 272,554 person-years during follow-up. A job exposure matrix was constructed to estimate exposure to particulate PAH and fluorides. The observed cases of cancer were compared with expected figures calculated from national rates. Dose-response relations were investigated by internal comparisons using Poisson regression and stratified analyses for standardized incidence ratio. Potential confounding by smoking was investigated in subanalyses restricted to 3 of the plants.

RESULTS

The study showed an overall excess for bladder cancer, standardized incidence ratio 1.3 (95% confidence interval 1.1-1.5), which increased with increasing cumulative exposure to PAH and reached a relative risk of about 2 for the upper exposure category in the analysis with 30 years of lag time. There was no association between cumulative PAH exposure and lung cancer, but there were indications of an elevated risk of kidney cancer among the most heavily PAH-exposed persons in the analyses with a lag time of 30 years. For pancreatic cancer we found a higher incidence among the PAH-exposed persons than among the unexposed ones, but no clear dose-response association was found.

CONCLUSIONS

The study showed an association between bladder cancer and exposure to PAH, but gave no support to an association between PAH exposure and lung cancer in the primary aluminum industry.

Serum organochlorine levels and breast cancer: a nested case-control study of Norwegian women

This study investigated the potential association between organochlorine exposure and breast cancer using stored sera collected from 1973 through 1991 from the Janus Serum Bank in Norway. Breast cancer cases were ascertained prospectively from among 25,431 female serum bank donors. A total of 150 controls were matched to cases by birth dates and dates of sample collection. One g of serum per subject was analyzed for a total of 71 organochlorine compounds. For 6 pesticides [B-hexachlorocyclohexane, heptachlor epoxide, oxychlordane, trans-nonachlor, p, p'-1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene, and p, p'-2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane] and 26 individual polychlorinated biphenyl (PCB) congeners there were >90% of samples over the limit of detection. There was no evidence for higher mean serum levels among cases for any of these compounds, nor any trend of increasing risk associated with higher quartiles of exposure. The remaining compounds (including dieldrin) were analyzed with respect to the proportion of cancer cases and controls having detectable levels; no positive associations were noted in these analyses. Our study did not confirm the recent findings of a Danish study of increased concentrations of dieldrin in the serum of breast cancer cases. The evidence to date on the association between serum organochlorines is not entirely consistent, but there is accumulating evidence that serum levels of p, p'-1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene and total PCBs are not important predictors for breast cancer in the general population. Studies to date have not been able to evaluate whether exposure to highly estrogenic, short-lived PCB congeners increases breast cancer risk, nor have they fully evaluated the risk associated with organochlorine exposure in susceptible subgroups or at levels above general population exposure, including women with occupational exposure.

Nonmalignant mortality among workers in six Norwegian aluminum plants

OBJECTIVES

This study investigated the associations between exposure to fluorides and polycyclic aromatic hydrocarbons (PAH) and mortality from nonmalignant diseases among workers in the Norwegian primary aluminum industry.

METHODS

Mortality among 10,857 men, employed for more than 3 years in 1 of 6 aluminum plants, was investigated from 1962 to 1996, giving 239,246 person-years during follow-up. Ajob-exposure matrix covering all 6 plants was used to estimate the individual exposure to total fluorides and particulate PAH. The observed cause-specific deaths were compared with expected figures calculated from national rates. Dose-response relations were investigated by internal comparisons using Poisson regression and by stratified analyses for standardized mortality ratio. Potential confounding by smoking was investigated in subanalyses restricted to 3 of the plants for which information on smoking habits was accessible.

RESULTS

Mortality from circulatory disease was slightly lower than expected [SMR 0.95, 95% confidence interval (95%CI) 0.9-1.0], while there was an increased mortality from asthma, emphysema, and chronic bronchitis combined, SMR 1.2 (95% CI 1.0-1.5). Mortality from these diseases was associated with cumulative exposure to fluorides. The rate ratio in the internal analysis rose steadily to 2.5 (95% CI 1.5-4.3) for the upper exposure category. No association was observed between cumulative fluoride exposure or PAH exposure and circulatory mortality.

CONCLUSIONS

The study showed an association between exposure to potroom emissions measured by fluorides and mortality from asthma, emphysema, and chronic bronchitis combined.

Applying pressure to financial bleeding. Medical group stanches the flow of red ink with an ASP

San Jose Medical Group, San Jose, Calif.

PROBLEM

A manual referral and authorization process resulting in significant monetary losses.

SOLUTION

Contracting with an application service provider that could provide real-time data on a continual basis.

RESULTS

Timely information on eligibility, referrals and authorizations before the patient leaves the office--patients going to the right doctors for the right services--and an in-depth understanding of associated costs.

KEYS TO SUCCESS

Taking a chance by going with an ASP--a company with little history.

Motor slowing and parkinsonian signs in aging rhesus monkeys mirror human aging

Motor slowing is a universal feature of human aging, and parkinsonian signs are commonly expressed in human senescence. In the present study, age-associated declines in motor functions in 31 female rhesus monkeys were quantified by activity monitors and an automated test panel, and the incidence of parkinsonian signs was scored using a movement dysfunction assessment scale. Activity levels in middle-aged monkeys (12-17 years old) were less than half that of young animals (5-8 years old) and were further depressed in aged monkeys (21-27 years old). Movement dysfunction scores increased significantly with increasing age. Two or more parkinsonian signs were exhibited by 20% of the middle-aged monkeys and 36% of the aged monkeys. Slowing performance times on fine-motor hand tasks correlated significantly with increasing age. Motor learning was seen in all age groups, but improved faster in the young monkeys. The data suggest that aging rhesus monkeys provide an appropriate model to analyze the biological processes leading to motor slowing and the expression of parkinsonian signs in human senescence.

Particle deposition in the nose related to nasal cavity geometry

A number of studies have been made to characterise the deposition-pattern of inhaled airborne particles in the nose. Common to all results has been considerable differences in deposition fractions between normal human subjects. It was the aim of the current study to improve our understanding of individual differences in nasal deposition of inhaled particles. Depositions were measured in ten adult normal subjects and were related to dimensional measurements by acoustic rhinometry. Five litres of a polydisperse aerosol (MMAD = 0.7 micron, sigma g = 1.7) were inhaled through one nostril only during 5 inspirations with flows of 10, 20, and 30 L/min with decongested mucosa. Increasing flow was found to increase the fraction deposited in the nose, while there was an inverse correlation between nasal deposition fraction and minimum cross-sectional area of the nasal cavity (Amin). Information based on acoustic rhinometry measurements significantly reduced the amount of unexplained variation between subjects in nasal deposition fraction. We conclude that an estimate of maximum linear air velocity, calculated as airflow divided by Amin, was the best single predictor of nasal deposition fraction, which was found to increase with increasing air velocity raised to a power of approximately 4/3.

Assessment of historical exposures in a nickel refinery in Norway

OBJECTIVES

The aim of the study was, on the basis of new information on nickel species and exposure levels, to generate a specific exposure matrix for epidemiologic analyses in a cohort of Norwegian nickel-refinery workers with a known excess of respiratory cancer.

METHODS

A department-time-exposure matrix was constructed with average exposure to total nickel estimated as the arithmetic mean of personal measurements for periods between 1973 and 1994. From 1972 back to the start of production in 1910, exposure concentrations were estimated through retrograde calculation with multiplication factors developed on the basis of reported changes in the metallurgical process and work environment. The relative distribution of water-soluble nickel salts (sulfates and chlorides), metallic nickel, and particulates with limited solubility (sulfides and oxides) was mainly derived from speciation analyses conducted in the 1990s.

RESULTS

The average concentration of nickel in the breathing zone was < or = 0.7 mg/m3 for all workers after 1978. Exposure levels for smelter and roaster day workers were 2-6 mg/m3 before 1970, while workers in nickel electrolysis and electrolyte purification were exposed to concentrations in the range of 0.15-1.2 mg/m3. The level of water-soluble nickel was of the same order for workers in the smelting and roasting departments as in some of the electrolyte purification departments.

CONCLUSIONS

Compared with earlier estimates, the present matrix probably offers a more reliable description of past exposures at the plant.

Hormone-dependent cancer and adverse reproductive outcomes in farmers' families--effects of climatic conditions favoring fungal growth in grain

OBJECTIVES

The impact of grain farming and climate on late-term abortion among female farmers, male genital birth defects among their sons, and hormone-dependent cancer among male and female farmers and their adult children was investigated.

METHODS

National registers were cross-matched in Norway and 246,043 male and female farmers born in 1925-1971 were identified, as were their 264,262 children, born in 1952-1980, in agricultural censuses and in the population register. The subjects were followed in the Cancer Register through 1995. Farmers' births, conceived in 1973-1991, were identified, and the prevalences of late-term abortion in mothers and hypospadias and cryptorchidism in their sons at birth were examined. Exposure, defined as the combination of grain farming and categories of seasonal or cumulative warnings, was based on data in agricultural censuses and on local, seasonal, field fungal warnings. Estimated adjusted rate ratios or prevalence ratios served as the measures of association.

RESULTS

Categories of high exposure were associated with reproductive outcomes and cancer among female farmers, the strongest occurring for late-term abortion (ratio 2.6, 95% confidence interval (95% CI) 1.6-4.3). Exposure associations for ovarian and breast cancer, and male genital defects, were more moderate. Endometrial cancer was associated with grain farming (ratio 2.0, 95% CI 1.4-2.8) across all levels of fungal warnings. Exposure associations for cancer were strongest for premenopausal, parous women. Exposure was not associated with cancer among male farmers or children.

CONCLUSIONS

Climatic conditions favoring fungal growth in grain were associated with hormone-dependent adverse outcomes among female farmers; the results are consistent with hormonal effects of inhaled mycotoxins during pregnancy.

Lung and bladder cancer among workers in a Norwegian aluminium reduction plant

OBJECTIVE

To investigate the relation between exposure to polycyclic aromatic hydrocarbons (PAHs) and the incidence of lung and bladder cancer among aluminium production workers.

METHODS

The cohort comprised 1790 men employed for more than 5 years at a Norwegian aluminium plant contributing 36 587 person-years to the study. Historical exposure to PAHs was estimated by the use of industrial hygiene measurements and by a panel of three people familiar with the industry. Cancer incidence was investigated from 1953 to 1995. The observed cases of cancer among men were compared with expected numbers calculated from national rates for men, and dose-response relations were investigated by internal comparison by Poisson regression with age, period, smoking, and cumulative exposure included in the models. The effect of lagging exposure by 10, 20, and 30 years was also investigated.

RESULT

The present study showed no increased risk of urinary bladder cancer or lung cancer with increasing cumulative exposure to PAHs. No significant changes in risk were found for different lag times.

CONCLUSIONS

Due to the small size of this study, a minor increase in risk could not be excluded.

Cancer incidence among male pulp and paper workers in Norway

OBJECTIVES

The study investigated cancer incidence among 23,718 male pulp and paper workers employed continuously for at least 1 year between 1920 and 1993 in Norway.

METHODS

The name, date of birth, personal identification number, dates of hire and termination for all employment periods, specific department, and job categories were registered for each worker. Six subcohorts were established (sulfite mill, sulfate mill, paper mill, maintenance department, administrative staff and other departments). Data on the cohort were linked with data in the Norwegian Cancer Register. The follow-up period for cancer incidence, date of death, or emigration was from 1953 through 1993.

RESULTS

An excess incidence of lung cancer was found among both short- and long-term employees [standardized incidence ratio (SIR) 1.5, 95% confidence interval (95% CI) 1.13-2.03 and SIR 1.2, 95% CI 1.09-1.34, respectively], especially for workers with the longest latency (SIR 1.3, 95% CI 1.08-1.44) and for sulfite mill workers (SIR 1.5, 95% CI 1.09-1.99). The risk for pleural mesothelioma was also increased (SIR 2.4, 95% CI 1.45-3.75), especially among maintenance workers. The results also showed an increased risk for malignant melanoma (SIR 1.3, 95% CI 1.04-1.60), an unexpected finding.

CONCLUSIONS

Almost all the increased risk for lung cancer can be explained by a combination of smoking habits and asbestos use. although an effect of other work-related exposures (sulfur and chloride compounds, wood dust) cannot be excluded. Most of the cases of pleural mesothelioma occurred in departments where asbestos was used. There is no clear explanation for the excess of malignant melanoma, and the finding may be a chance occurrence.

Variability in methotrexate serum and cerebrospinal fluid pharmacokinetics in children with acute lymphocytic leukemia: relation to assay methodology and physiological variables

Methotrexate (MTX) steady state concentrations were evaluated in 42 children who had received high-dose infusions (6-8 g/m2) for acute lymphocytic leukemia. Concentrations in serum and cerebrospinal fluid (CSF) measured by immunoassay were found to be highly variable. Reanalysis by a reference high-pressure liquid chromatography method ruled out analytical factors as a source of this variability. The correlation coefficient between the analytical methods was 0.77 for the serum data and 0.88 for the CSF data. The variability of serum and CSF concentrations was higher in younger patients (serum; P = 0.05 and CSF; P = 0.18), and the CSF concentration decreased with decreasing age and in later courses. Body surface area, body mass index, weight, and gender were not significantly related to MTX variability. We conclude that the pronounced pharmacokinetic variability seen during MTX infusions remains largely unexplained.

Cancer incidence and cause specific mortality among workers in two Norwegian aluminum reduction plants

BACKGROUND

Concern about the health hazards in the aluminum industry has initiated this study where we have investigated associations between exposure to polycyclic aromatic hydrocarbons (PAH) and fluorides, and cancer incidence and cause specific mortality among workers in two Norwegian aluminum plants in operation since 1954 and 1957, respectively.

METHODS

The study was designed as a historical cohort study and comprised 5627 identified men employed for more than six months. Cancer incidence was investigated from start of employment to 1995, and cause specific mortality was investigated from 1962 to 1995. The observed cases of cancers and observed deaths were compared with expected numbers calculated from national rates. Internal comparisons were made using Poisson regression with age and smoking included in the models. Historical exposure to PAH and fluoride had been estimated previously by use of statistical modeling on industrial hygiene measurements and process parameters. A job exposure matrix was used to investigate possible associations between cumulative exposures, and cancer incidence and cause specific mortality. Smoking habits were identified for 92% of the cohort members.

RESULTS

The study showed a significant excess risk for urinary bladder cancer among workers exposed to PAH, but no clear dose-response relationship. When using a 30-year lag period, a significant excess of bladder cancer in the highest exposure category (> 2000 microg/m(3);year PAH) was shown (SIR 4.08). The data also suggested an association between exposure to PAH and pancreatic cancer, but no association with lung cancer was seen. The mortality analysis indicated an association between exposure to pot-room emissions (fluorides) and mortality from chronic bronchitis, emphysema and asthma, but no associations with cardiovascular diseases.

CONCLUSIONS

The study findings are compatible with an excess risk for bladder cancer for aluminum plant workers exposed to PAH. The increased risk for cancer of the pancreas indicated, should be further evaluated in larger exposed populations.

Incidence of cancer among workers exposed to vinyl chloride in polyvinyl chloride manufacture

Based on results from two previous studies where an excess of melanomas was found in a cohort of workers exposed to vinyl chloride (VCM), a follow up of the incidence of cancer in the same cohort of 428 workers was carried out to scrutinize whether or not the excess could be confirmed by new cases. The total number of deaths in the study group from 1953 to the end of 1993 was 132 v 141 expected, and the total number of incident cancer cases was 56 v 57 expected. There were 11 cases of lung cancer v eight expected, seven cases of melanomas v 2.07 expected, and two cases of thyroid cancer v 0.34 expected. Five of the seven melanoma cases had occurred in the group that had been most heavily exposed to VCM v 0.7 expected. In the present follow up we also found five cases of the spinocellular cancer of the skin v 1.7 expected. Out of these five cases four were diagnosed after 1984. Two of the five cases v 0.7 expected had occurred in the most heavily exposed group. The total number of skin cancers (melanomas and spinocellular cancers) were 12 v 3.7 expected. There was one new case of melanoma between 1985 and 1993 v 0.7 expected. Hence, the strength of the relation between the observed and expected number of cases was reduced compared with the last follow up, and does not strengthen the previously indicated causal relation between exposure to VCM and development of malignant melanoma. There was no excess of testicular cancers in this study. The present results may indicate that occurrence of spinocellular skin cancer could bear some relation to work in the manufacture of polyvinyl chloride (PVC). Confirmation is needed from studies on other cohorts exposed to VCM.

Incidence of cancer among welders and other shipyard workers with information on previous work history

The incidence of cancer among 4480 shipyard workers, including 861 welders, was investigated for a potential relationship between exposure to welding fumes and lung cancer. A subcohort of 3150 workers with information on previous work history was studied separately. This investigation is a historical prospective cohort study. Environmental air samples were collected in 1973, 1977, and 1989. Information on smoking habits was surveyed in 1976 and 1984. The employment work histories were collected from the personnel register. There were 411 observed cancers of all sites versus 387.5 expected, and 45 cases of lung cancer versus 51.3 expected. Nine cases of lung cancer were found among the welders versus 7.1 expected. Among 310 former seamen with welding experience, there was 1 case of lung cancer versus 2.1 expected. These shipyard workers showed no excess risk of lung cancer. Tobacco smoking and asbestos exposure are potential confounders in the study. There was no clear relationship between exposure to welding fumes and lung cancer, but welders with the longest experience had a relative risk of 1.9 for lung cancer. The differences in lung cancer incidence among the different shipyard workers could not be attributed to differences in recruitment patterns or previous work history.

Gender differences in the healthy worker effect among synthetic vitreous fiber workers

The aim of this study was to determine whether the healthy worker effect and its component parts operate similarly for women and men. A cohort of workers from 14 synthetic vitreous fiber factories in seven countries, employed for at least 1 year between 1933 and 1977 and followed up to the early 1990s, included 375 deaths and 53,608 person-years among females and 2,568 deaths and 210,073 person-years among males. Standardized mortality ratios for all-cause and circulatory diseases were adjusted for country, age, calendar time, and gender. In addition, internal comparisons were adjusted for time since hire and employment status. The analyses addressed the following: 1) the healthy hire effect, 2) the time since hire effect, and 3) the healthy worker survivor effect. In this cohort, an overall healthy worker effect was not present in either gender. The healthy hire effect, based on standardized mortality ratios for years 1-4 since hire, was observed in males (standardized mortality ratio (SMR) = 0.8; 95% confidence interval (CI): 0.7, 1.0) but was less in females (SMR = 0.9; 95% CI: 0.5, 1.6). The relative risks increased slightly with time since hire in males but not in females. Higher mortality ratios were seen among those leaving employment than among those who remained actively employed; however, this effect was substantially greater for women (relative risk (RR) = 3.4; 95% CI: 1.8, 6.3) than men (RR = 1.8; 95% CI: 1.5, 2.1). The gender difference for active versus inactive status was stronger up to age 60 (men: RR = 1.7; 95% CI: 1.4, 2.0; women: RR = 3.6; 95% CI: 1.8, 7.1) than above that age. In conclusion, it appears that there is a stronger selection of healthy men than women into the workforce, while health-related selection out of the workforce is stronger for women than men.

Work-related cancer in the Nordic countries

This report presents 20 years' of cancer incidence data by occupational group for the Nordic populations. The study covers the 10 million people aged 25-64 years at the time of the 1970 censuses in Denmark, Finland, Norway, and Sweden, and the 1 million incident cancer cases diagnosed among these people during the subsequent 20 years. The project was undertaken as a cohort study with linkage of individual records based on the personal identification numbers used in all the Nordic countries. In the 1970 censuses, information on occupation for each economically active member of the household was provided in free text in self-administered questionnaires. The data were centrally coded and computerized in the statistical offices. Norway, Sweden, and Finland used the Nordic Classification of Occupations, while Denmark used a national coding scheme. However, all the data could be reclassified into 53 occupational groups and 1 group of economically inactive persons. Person-years at risk were accumulated from 1 January 1971 until the date of emigration, date of death or 31 December 1987 in Denmark, 1989 in Sweden, 1990 in Finland, and 1991 in Norway. The 4 countries all had nationwide registration of incident cancer cases during the entire study period. All incident cancer cases during the individual risk periods were included in the analysis. Despite minor differences between the countries, the International Classification of Diseases, 7th revision, formed the core basis for the diagnostic coding in all 4 countries. For the present study the incident cancer cases have been classified into 35 broad diagnostic groups. The observed number of cancer cases in each group of persons defined by country, gender, and occupation was compared with the expected number calculated from the age-, gender-, and period-specific person-years and the incidence rates for the national population. The result has been presented as a standardized incidence ratio (SIR), defined as the observed number of cases divided by the expected number and multiplied by 100. In the tables of this report, all the SIR values for which the upper limit of the 95% confidence interval is below 100 are printed in green and all those for which the lower limit of the confidence interval is above 100 are printed in red. For all cancers combined, the study showed a wide variation among the men, from an SIR of 79 for farmers to 159 for waiters. The occupations with the highest SIR values also included seamen and workers producing beverages and tobacco. Among the women the SIR values varied from 83 for gardeners to 129 for tobacco workers. Low SIR values were found for farmers and teachers. Outdoor workers such as fishermen and gardeners had the highest risk of lip cancer, while the lowest risk was found among indoor workers such as physicians and artistic workers. Almost all pleural cancers are associated with asbestos exposure. Accordingly, plumbers, welders, mechanics, and seamen were the occupations with the highest risk. There was also an excess risk of pleural cancer in the occupational group of technical, chemical, physical, and biological workers, including, among others, engineers and chemists potentially exposed to asbestos. The wood workers included in the present study had the highest risk of nasal cancer. Most studies of nasal cancer have shown increased risks associated with exposure to wood dust, both for those in furniture making and for those exposed exclusively to soft wood. Nickel refinery workers are also known for their high risk of nasal cancer. In the present study they were included in the occupational group of smelting workers. Lung cancer was the most frequent cancer among men in the present study. Tobacco smoking is the major risk factor for this disease, but occupational exposures also play an important role. Waiters and tobacco workers had the highest risk of lung cancer. Miners and quarry workers also had a high risk of lung cancer, which may be related to

Pharmacokinetics and metabolism of doxorubicin after short-term infusions in lymphoma patients

PURPOSE/METHODS

Twenty-four patients (17 males and 7 females with a mean age of 54 years) with malignant lymphoma participated in a study of doxorubicin pharmacokinetics after 50 mg/m(2) as 10-min infusions. In addition to plasma samples, serial leukocyte samples and - in one subject - serial biopsy specimens from lymphoma infiltrates were obtained. The samples were analysed by reversed-phase high-performance liquid chromatography.

RESULTS

In contrast to several previous studies, the data suggested that 7-deoxydoxorubicinolone, and not doxorubicinone, is a metabolite of doxorubicin in humans. Doxorubicin, but no metabolites, was present in significant and fairly constant concentrations in circulating leukocytes. These levels may reflect the drug levels in lymphoma infiltrates. The data further suggest that metabolism to 7-deoxydoxorubicinone is subject to large interindividual variation, possibly due to a genetic polymorphism, and that significant levels of a metabolic product which may be a doxorubicin glucuronide can be recovered from plasma of patients treated with doxorubicin.

Non-neoplastic mortality of European workers who produce man made vitreous fibres

OBJECTIVE

To study mortality from non-neoplastic diseases among European workers who produce man made vitreous fibres (MMVF).

METHODS

11,373 male workers were studied, who were employed for at least 1 year in the production of rock or slag wool (RSW), glass wool (GW), and continuous filament (CF) in 13 factories from seven European countries. Workers were followed up from the beginning of production, between 1933 and 1950 to 1990-2 and contributed 256,352 person-years of observation. Standardised mortality ratios (SMRs) were calculated with national mortalities for reference; an internal exposure-response analyses based on multivariate Poisson regression models was also conducted.

RESULTS

Mortality from bronchitis, emphysema, and asthma was not increased (SMR 1.03, 95% confidence interval (95% CI) 0.82 to 1.28). In RSW workers, there was no overall increase in mortality from non-malignant renal diseases (SMR 0.97, 95% CI 0.36 to 2.11), although there was the suggestion of an increase in risk with duration of employment. Mortality from ischaemic heart disease was not increased overall (SMR 1.03, 95% CI 0.96 to 1.11), but RSW and CF workers with > or = 30 years since first employment had a higher risk. RSW and CF workers showed an increased mortality from external causes, mainly motor vehicle accidents and suicide, which was higher among workers with a short duration of employment.

CONCLUSIONS

Mortality from most non-neoplastic diseases does not seem to be related to employment in the MMVF industry. The results on mortality from ischaemic heart disease and non-malignant renal diseases, however, warrant further investigations.

Epstein-Barr virus and cytomegalovirus in relation to testicular-cancer risk: a nested case-control study

An infectious etiology of testicular cancer has been suggested. We have evaluated seroreactivity against cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in relation to testicular-cancer risk in a case-control study, nested within a cohort of prospectively collected serum specimens from 293,692 individuals. For each of 81 cases of testicular cancer identified, 3 controls were randomly selected from the cohort. Serum IgG antibody titers against CMV and EBV were determined using enzyme-linked immunosorbent assays (ELISAs) and immunofluorescence methods. Odds ratios (OR) were obtained from conditional logistic-regression models. No association was found between CMV positivity and testicular cancer overall (OR = 1.08; 95% confidence interval 0.60-1.94); risk for testicular seminoma was increased among CMV seropositive [OR = 1.70 (0.80-3.59)], whereas seropositivity was associated with decreased risk for testicular non-seminoma [OR = 0.54 (0.19-1.56)] (p for heterogeneity, 0.09). For EBV, the risk for testicular cancer was increased among individuals seropositive for viral capsid antigen (VCA) [OR = 2.74 (0.62-12.12)]. The results lend some support to the hypothesis of an infectious etiology, and we propose that future studies should take into account age at infection.

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.