[Occupational diseases and preventive health care].
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Humans↗
Biomedical subjects
H Kjuus
Publications and source records attributed to H Kjuus.
Production and surveillance of mercury exposure over 40 years at a chloralkali plant.
Mercury vapour exposure was studied for 40 years in 419 chloralkali workers. The concentration of mercury was measured in the work room (stationary) from 1953 and in urine from 1948. There were major differences in the mean urinary concentrations between different types of job. The mean urinary mercury concentration, uncorrected for urinary dilution, for all subjects varied between 30 and 250 micrograms 1.(-1) during the study period. For workers in the cell-room the correlation (r) between urinary mercury and mercury in the work room was r = 0.74 (P < 0.001), and for repair men/mechanics it was r = 0.70 (P < 0.001). The introduction of new cells and stabilizing the volume of production may have been important for reducing air-Hg and U-Hg, whereas other changes in the production process, or actions to reduce the release of mercury to the work environment, had no detectable effect. The urinary mercury concentration among all workers was related to the relative energy consumption (r = 0.83, P < 0.001).
Air Pollutants, Occupational↗
An immunological study of chloralkali workers previously exposed to mercury vapour.
Several animal studies have suggested that exposure to inorganic mercury compounds may have effects on the immune system. Human data are, however, relatively sparse. The presence of several autoantibodies and the concentration of immunoglobulins and complement components were determined in the present cross-sectional study in 77 chloralkali workers previously exposed to mercury vapour and 53 age-matched referents. The mean duration of exposure to mercury vapour was 7.9 years (range 1.1-36.2), and the exposure had ceased on average 12.3 years (range 1.0-35.0) prior to the examination. No increased prevalence of the studied autoantibodies was observed among the exposed subjects as compared with the referents. There were no significant differences in the concentrations of immunoglobulins or complement components between the two studied groups. Nor was any relationship observed between cumulative mercury dose estimates or time since cessation of exposure and the measured concentrations of immunoglobulins or complement components.
Adult↗
Dental health in workers previously exposed to mercury vapour at a chloralkali plant.
OBJECTIVES: The dental health of 73 workers previously exposed to mercury vapour at a chloralkali plant was studied and compared with that of 51 non-exposed referents. METHODS: A record of oral, periodontal, gingival and mucosal conditions, including teeth, restorations, prostheses, and oral hygiene, was established during a 30 min examination. The participants' periodontal conditions were assessed according to the community periodontal index of treatment needs (CPITN). The results with the CPITN index were also compared with previously published data for another similar population. RESULTS: There was no significant difference between the exposed workers and the referents with respect to the number of remaining teeth, amount of amalgam restorations, crowns, bridges, or endodontically treated teeth. The oral hygiene among the exposed workers was significantly better than among the referents, but the periodontal health conditions did not significantly differ between the two groups, nor from those of another Norwegian population. DISCUSSION: The present results seem to contradict previous reports claiming tooth loss as a possible result of exposure to mercury vapour.
Adult↗
Exposure to stainless steel welding fumes and lung cancer: a meta-analysis.
Stainless steel welding is associated with exposure to metals including hexavalent chromium and nickel. This study is a meta-analysis of five studies of stainless steel welders and the occurrence of lung cancer. Asbestos exposure and smoking habits have been taken into account. The calculated pooled relative risk estimate was 1.94 with a 95% confidence interval of 1.28-2.93. This result suggests a causal relation between exposure to stainless steel welding and lung cancer.
Causality↗
Bronchial responsiveness and decline in FEV1 in aluminium potroom workers.
We have investigated the relationship between annual decline in forced expiratory volume in one second (delta FEV1) and bronchial responsiveness (BR) in aluminium potroom workers. BR was measured in a cross-sectional study of 337 aluminium potroom workers half-way through a 6 yr follow-up study of lung function. A skin-prick test (SPT) was also performed. During follow-up the mean number of measurements of lung function (FEV1) in each subject was 6.8. Mean delta FEV1 was 21.3 ml.yr-1 (within subject SD = 30.5 ml.yr-1). Mean delta FEV1 was 57.0, 44.5 and 16.6 ml.yr-1 in subjects who had provocative concentration producing a 20% fall in FEV1 (PC20) < or = 8.0, 8.1-32.0 and > 32.0 mg.ml-1, respectively. After adjustment for gender, atopy, smoking habit, FEV1, age and familial asthma the association between BR and delta FEV1 was weakened, and was not statistically significant. A significantly accelerated decline in FEV1 with age was found. The difference in delta FEV1 between smokers and nonsmokers was 39.3 ml.yr-1, and between subjects who had a positive skin-prick test compared to subjects with a negative skin-prick test 39.6 ml.yr-1. In subjects reporting work-related asthmatic symptoms the decline in FEV1 was 43.2 ml.yr-1 greater than in asymptomatic subjects. In asymptomatic subjects, positive skin-prick test was also associated with increased delta FEV1. These data indicate that a single measurement of BR is not a predictor of delta FEV1 in aluminium potroom workers. Smoking, work-related asthmatic symptoms, and positive reaction to skin-prick test in asymptomatic workers were risk factors of increased delta FEV1.
Adolescent↗
A neurological and neurophysiological study of chloralkali workers previously exposed to mercury vapour.
Neurological and neurophysiological examinations were conducted in 77 former chloralkali workers previously exposed to mercury vapour and 53 referents. The exposure had ceased on average 12.3 years prior to the study. There was a higher prevalence of reduced distal sensation (13.0% vs 1.9%), postural tremor (18.2% vs 7.5%) and impaired coordination (10.4% vs 1.9%) among the exposed subjects as compared to the referents. Abnormal Romberg's test (6.5% vs 0%) and line walking (7.8% vs 0%) were also more prevalent. The first negative peak in visual evoked response (N75) was bilaterally prolonged, and the median motor (55.9 m/s vs 58.0 m/s) and sensory nerve conduction velocity (55.6 m/s vs 59.0 m/s) were slightly reduced among the highly exposed subjects. The results indicate that slight neurological abnormalities, which in most cases could not be classified as disease, may persist many years after exposure cessation.
Adult↗
Incidence of cancer and mortality among workers exposed to mercury vapour in the Norwegian chloralkali industry.
Incidence of cancer and mortality were studied among 674 men exposed to mercury vapour for more than one year at two chloralkali plants. Mercury excretion in urine had been monitored among the workers at the two plants since 1948 and 1949. An individual cumulative urinary mercury dose was calculated, based on about 20,000 urinary mercury measurements. The incidence of cancer and the mortality were followed up from 1953 to 1989 and 1953 to 1988 respectively. The general Norwegian male population served as a reference population. There was a lung cancer excess of borderline significance (standardised incidence ratio = 1.66, 95% confidence interval = 1.00-2.59). The introduction of a 10 year latent period before developing lung cancer did not increase the incidence ratio. The excess may be partly explained by the smoking habits in the cohort or possibly by exposure to asbestos. No excess of cancer was found in the target organs for mercury toxicity--namely, the kidney and the nervous system. No significant excess mortality was found for nephritis and nephrosis or nonmalignant diseases of the nervous system.
Chemical Industry↗
Assessment of renal dysfunction in workers previously exposed to mercury vapour at a chloralkali plant.
Urinary albumin concentration (U-alb) and N-acetyl-beta-D-glucosaminidase (U-NAG) and glomerular basement membrane antibodies (a-GBMs) in serum samples were measured in 77 chloralkali workers previously exposed to mercury (Hg) vapour and 53 age matched referents. The exposure ceased on average 12.3 (range 1-35) years before the study. The mean exposure time was 7.9 (range 1.1-36.2) years. The mean yearly urinary Hg concentration (U-Hg) was 531 nmol/l. The concentrations of the urinary isoenzymes NAG A (U-NAG A) and NAG B (U-NAG B) were determined in 30 highly exposed subjects and 30 referents. No differences in U-alb or U-NAG, U-NAG A, or U-NAG B were found between the groups. Higher concentrations of a-GBMs were found among subjects who stopped exposure a short time before the study, but there was no association between a-GBMs and U-alb. The U-NAG and U-NAG A were negatively correlated with storage time. The results may suggest that microalbuminuria and enzymuria reported in subjects with ongoing exposure to Hg vapour are reversible in most instances.
Acetylglucosaminidase↗
Incidence of cancer among workers in a Norwegian nitrate fertiliser plant.
The incidence of cancer among 2023 male fertiliser workers has been investigated in a historical cohort study. Workers who had been employed for more than one year in work with possible exposure to dust containing nitrate between 1945 and 1979 were included. An individual cumulated exposure to dust expressed in level-years was calculated for each participant. The cohort was followed up from 1953 to the end of 1988, and the incidence of cancer was compared with the national rates. There were 467 deaths v 504.8 expected (standardised mortality ratio (SMR) = 0.93), and 185 cases of cancer v 195.5 expected (standardised incidence ratio (SIR) = 0.95). Thirty cases of lung cancer were found v 27.5 expected (SIR = 1.09). No overall excess of gastric cancer was found (15 cases v 17.0 expected; SIR = 0.89). No association was found between cumulated exposure to nitrate and gastric cancer, and there was no association between duration of employment or time since first employment and incidence of gastric cancer.
Cohort Studies↗
Relation between exposure related indices and neurological and neurophysiological effects in workers previously exposed to mercury vapour.
A cross sectional study of aspects of their neurology was carried out on 77 chloralkali workers previously exposed to mercury (Hg) vapour and compared with 53 age matched referents. The chloralkali workers had been exposed for an average of 7.9 years at a concentration of 59 micrograms Hg/m3 in the working atmosphere. The individual mean urinary concentration of Hg for each year of exposure was 531 nmol Hg/1. On average the exposure had ceased 12.3 years before the examinations. Both the median sensory nerve conduction velocity and the amplitude of the sural nerve were associated with measures of cumulative exposure to Hg. An association was also found between years since first exposure to Hg and aspects of the visual evoked response. Previously exposed subjects with postural tremor or impaired coordination also had alterations in visual evoked response. These results may indicate an effect of previous exposure to mercury vapour on the nervous system, possibly in the visual pathway, cerebellum, and the peripheral sensory nerves.
Adult↗
Mercury and selenium in workers previously exposed to mercury vapour at a chloralkali plant.
The concentrations of total mercury (B-Hg), inorganic mercury (B-IHg), and methyl mercury (B-MeHg) in whole blood, urinary mercury (U-Hg), and selenium in urine (U-Se) and whole blood (B-Se) were determined in 74 chloralkali workers previously exposed to Hg vapour, and compared with 51 age matched referents. Dental amalgam state, fish consumption, and exposure related indices were studied with regard to the determined elements. A significant relation between the surface of dental amalgam and U-Hg (Pearson's r = 0.63, p < 0.001) was found among the referents. Mean U-Se was significantly lower (p < 0.001) among the subjects previously exposed to Hg (34.1 nmol/mmol creatinine) compared with that for the referents (42.6 nmol/mmol creatinine). A significant negative relation between the cumulative Hg dose and U-Se was also found. The mechanisms and the clinical significance of these findings are not clear. No relation between current U-Hg and previous occupational exposure to Hg was found among subjects in whom exposure had ceased more than one year before the study.
Adult↗
Chromosome aberrations in chloralkali workers previously exposed to mercury vapor.
Chromosome aberrations and micronuclei in peripheral lymphocytes were studied in 29 male chloralkali workers previously exposed to mercury vapor and in two matched reference groups comprising 29 nitrate fertilizer workers and 29 customs and police officers. The study was performed using whole-blood cultures with and without hydroxyurea and caffeine to inhibit deoxyribonucleic acid synthesis and repair, respectively. No significant differences in the frequencies of chromosome aberrations and micronuclei were observed. However, a nonsignificant increase in chromosome breaks and dicentrics was found in the subgroups with high urinary mercury peak levels or high cumulative mercury exposure. An increased prevalence of "high" scores of chromatid breaks in the inhibited cultures, exceeding the 75th percentile of all of the subjects studied, was observed for the chloralkali workers when compared with both reference groups. No evident cytogenetic effects were observed among the chloralkali workers with the methods used in the present study.
Adult↗
Urinary mercury excretion in chloralkali workers after the cessation of exposure.
Seventeen former chloralkali workers were followed through the regular determination of urinary mercury for nearly two years after the cessation of exposure to mercury vapor in a study of the time course of urinary mercury elimination. Their duration of exposure ranged from 3 d to 35.5 years. A one-compartment model for urinary mercury elimination was applied. The urinary mercury concentration declined at a rate indicating a half-time of 91 d. When corrected for an individual base-line level of urinary mercury resulting from sources of mercury intake not related to work, the half-time was 72.4 [95% confidence interval (95% CI) 63.2-81.7] d, with a mean elimination rate constant of 0.011 (95% CI 0.008-0.013).d-1. The day-to-day variability of the urinary mercury concentration averaged 22%, expressed as the coefficient of variation between urine samples delivered on three consecutive days.
Adolescent↗
[The status of occupational medicine in the Scandinavian countries].
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Occupational Medicine↗
Cancer incidence among workers in the Norwegian ferroalloy industry.
The total mortality and the incidence of cancer was studied among a cohort of employees at the six oldest ferrosilicon and ferromanganese plants in Norway. The cohort consisted of 6494 men employed for more than 18 months before 1970 and has been followed up from 1953 to 1982. The standardised incidence ratio (SIR) for cancer (all sites) was 0.94. The observed number of cancers was as expected for lung cancer (SIR = 0.99) and for most of the other cancer sites studied. A statistically significant reduction of stomach cancer was found (SIR = 0.72). There was an increased incidence of lung cancer (SIR = 1.75) and cancer of the prostate (SIR = 1.56) in the workers at one ferrosilicon plant and of colonic cancer (SIR = 1.90) at another ferrosilicon plant.
Female↗
Incidence of cancer among workers producing calcium carbide.
The overall mortality and the incidence of cancer have been studied among male employees at a plant producing calcium carbide. The cohort was defined as all men employed at the plant for at least 18 months in the period 1953 to 1970 and was classified according to 10 occupational categories. The 790 men have been observed from 1953 to 1983 and the incidence of cancer in the cohort has been compared with national incidence rates. A significant excess of colonic cancer (standardised incidence ratio, SIR = 2.09) and of prostatic cancer (SIR = 1.78) was found, and also a slight excess of lung cancer among furnace and maintenance workers (SIR = 1.56). The possible exposure of the workers to polycyclic aromatic hydrocarbons, asbestos, and cadmium is discussed.
Acetylene↗
A case-referent study of lung cancer, occupational exposures and smoking. III. Etiologic fraction of occupational exposures.
The proportion of lung cancer related to occupational exposure to respiratory carcinogens and other workplace contaminants has been studied in a hospital-based case-referent study of 176 incident cases and 176 referents, recruited from the medical ward of two county hospitals in southern Norway. On the basis of job title and exposure information, three different approaches for the estimation of etiologic fraction were used, all based upon a trichotomous categorization of the exposure variable. Among the definitely exposed subjects, the etiologic fraction for lung cancer related to occupational exposure factors was from 22 to 35%, increasing to 37-47% when the "possibly exposed" categories were included. When asbestos was the only factor to be eliminated, the etiologic fraction estimate suggested a 23% reduction in the lung cancer incidence in the study population. More than 90% of the lung cancer cases would theoretically have been prevented if smoking had been completely removed. The relative merits of preventing one or several of the study factors simultaneously is discussed.
Adult↗