Showing papers in "Scandinavian Journal of Work, Environment & Health in 1990"

Psychophysical scaling with applications in physical work and the perception of exertion

Abstract: In studies on work it is important to assess various subjective symptoms, complaints, and annoyances. To measure such symptoms, psychophysical ratio scales may be used, as along with simpler category rating scales. In this paper some of the basic concepts and methods of psychophysics have been described. In the field of heavy physical work and the perception of effort and exertion, one of the most popular methods is the rating of perceived exertion. This scale has been presented together with a new category ratio scale, commonly referred to as the CR-10 scale. Some situations in which it is important to obtain measurements of perceived exertion have also been described in the paper.

Psychological and psychophysiological effects of shift work

Abstract: The psychophysiology of shift work is mainly related to circadian rhythmicity and sleep-wake phenomena. Individuals on a rotating three-shift or similar system work the night shift at the low phase of circadian rhythm. On retiring to bed in the morning they fall asleep rapidly but are prematurely awakened by their circadian rhythm and exhibit severe sleepiness and reduced performance capacity. In connection with the morning shift the circadian psychophysiology makes it difficult to fall asleep as early as needed during the preceding night. Around 0400 to 0500, when the individuals should rise, they have difficulties awakening because of the sleep loss and the circadian rhythm, which at that point is at its lowest. Subsequently, day work is characterized by sleepiness and reduced performance. It should be emphasized that it does not seem possible to improve one's ability to adjust over time, even with permanent night work. Older age and "morningness" personality are related to higher than average problems in adjusting.

Influence of indoor climate on the sick building syndrome in an office environment. The Danish Indoor Climate Study Group.

Abstract: The influence of indoor climate factors on symptoms of the sick building syndrome was investigated in Greater Copenhagen, Denmark. Altogether, 2369 office workers in 14 buildings, where indoor climate measurements were made, filled out a questionnaire. Multivariate logistic regression analyses of the multifactorial effects on the prevalence of work-related mucosal irritation and work-related general symptoms among the office workers showed that the concentration of macromolecular organic floor dust, the floor covering, the number of workplaces in the office, the age of the building, the type of ventilation, and two easily recognizable factors, the shelf factor and the fleece factor, were associated with the prevalence of symptoms.

Indoor air quality and personal factors related to the sick building syndrome.

Abstract: The "sick building syndrome" involves symptoms such as eye, skin and upper airway irritation, headache, and fatigue. A multifactorial study was performed among personnel in consecutive cases of sick buildings to investigate relationships between such symptoms, exposure to environmental factors, and personal factors. The total indoor hydrocarbon concentration was significantly related to symptoms. Other indoor exposures such as room temperature, air humidity, and formaldehyde or carbon dioxide concentration did not correlate with the symptoms. Personal factors such as reported hyperreactivity and sick leave due to airway diseases were strongly related to the sick building syndrome. Other factors associated with the sick building syndrome were smoking, psychosocial factors, and experience of static electricity at work. Neither atopy, age, sex, nor outdoor exposures correlated significantly with the number of symptoms. It was concluded that the sick building syndrome is of multifactorial origin and related to both indoor hydrocarbon exposure and individual factors.

Prevalence of adverse reproductive outcomes in a population occupationally exposed to pesticides in Colombia.

Abstract: A prevalence survey of adverse reproductive outcomes was carried out in a population of 8867 persons (2951 men and 5916 women) who had been working in the floriculture industry in the Bogota area of Colombia for at least six months. These workers were exposed to 127 different types of pesticides. The prevalence rates for abortion, prematurity, stillbirths, and malformations were estimated for pregnancies occurring among the female workers and the wives of the male workers before and after they started working in floriculture, and these rates were related to various degrees of exposure. A moderate increase in the prevalence of abortion, prematurity, and congenital malformations was detected for pregnancies occurring after the start of work in floriculture.

Symptoms of the Neck and Upper Extremities in Dentists

Abstract: Symptoms of the neck, shoulders, arms, and hands of 99 dentists and a reference group of 100 pharmacists were studied by means of a telephone interview. Forty-four percent of the dentists and 26% of the pharmacists reported symptoms of the neck [relative risk (RR) 2.1, 95% confidence interval (95% CI) 1.4-3.1]. Symptoms of the shoulder were reported by 51% of the dentists and 23% of the pharmacists (RR 2.2, 95% CI 1.5-3.3). Musculoskeletal symptoms in the forearm were present almost exclusively in the dentists (12 versus 1%). Numbness and paresthesia were more common among the dentists than among the referents (RR 4.2, 95% CI 2.3-7.7). Unilateral Raynaud's phenomenon in the dominant hand occurred in six dentists and one pharmacist. The high frequency of symptoms from the neck, shoulders, and upper extremities of the dentists was probably related to their difficult work positions with cervical flexion and rotation, abducted arms, and repetitive precision-demanding handgrips.

Risk of spontaneous abortion among nurses handling antineoplastic drugs.

Abstract: The purpose of the study was to evaluate the frequency of spontaneous abortion in two groups of women. One group consisted of women regularly involved in the preparation of cancer chemotherapy perfusions and therefore considered to be exposed to cytostatic agents; the other consisted of women not occupationally exposed to such agents. The study was carried out in four French hospitals. Four hundred and sixty-six women were involved; 534 pregnancies were described in which 139 were exposed and 357 were unexposed. The results showed that the frequency of spontaneous abortion was 26% for the exposed pregnancies and 15% in the unexposed ones (odds ratio 2.0). These results do not seem to be due either to the classic risk factors of spontaneous abortion (age, cigarette consumption during pregnancy, pregnancy order) (adjusted odds ratio 1.7) or to possible errors concerning the retrospective evaluation of prior gynecologic and obstetric history.

Epidemiologic evidence on the relationship between formaldehyde exposure and cancer.

Abstract: Over 30 epidemiologic studies have evaluated cancer risks associated with formaldehyde exposure. Excesses were reported for several sites, leukemia and cancers of the nasal cavities, nasopharynx, lung, and brain generating the greatest interest. The excesses of leukemia and brain and colon cancer found among professionals may not be related to formaldehyde exposure, since similar excesses were not observed among industrial workers. Inconsistencies among and within studies impede assigning formaldehyde a convincing causal role for the excesses of lung cancer found among industrial workers. A causal role for formaldehyde is the most probable for cancers of the nasopharynx and, to a less extent, the nasal cavities. Evidence of exposure-response relationships, the fact that direct contact with formaldehyde may occur at these upper respiratory sites, and the consistency of these findings with experimental studies make this assumption highly probable.

Uptake, distribution and elimination of alpha-pinene in man after exposure by inhalation.

Abstract: The toxicokinetics of alpha-pinene were studied in human volunteers exposed by inhalation (2 h, 50 W) in an exposure chamber on four occasions. The exposures were about 10, 225, and 450 mg/m3 (+)-alpha-pinene and 450 mg/m3 (-)-alpha-pinene. The relative pulmonary uptake was about 60% for the higher exposures, and total uptake increased linearly with increasing exposure. The total blood clearance was high, about 1.11.h-1.kg-1. After the exposure was terminated, less than 0.001% of the total uptake was eliminated unchanged in the urine and about 8% in exhaled air. A long half-time in poorly perfused tissues indicates a high affinity to adipose tissues. There was a statistically significant exposure-response relationship among five subjects who experienced irritation. Short-time exposure to alpha-pinene did not give rise to acute changes in lung function 20 min after the exposure.

Birth defects among children born to a population occupationally exposed to pesticides in Colombia.

Abstract: A case-referent study of birth defects was nested in a prevalence survey of adverse reproductive outcomes carried out among 8867 floriculture workers in Bogota, Colombia. A total of 535 children born to these workers and reported by their parents as malformed and 1070 children selected at random as referents were invited to a medical examination including consultation with a geneticist and a clinical teratologist and a review of the medical records. Seventy-six percent of both groups attended the examination. Of 403 children reported as malformed, a birth defect was confirmed for only 154 (38%). On the other hand, of the 817 children reported as normal, 735 (90%) were normal, but 68 had a birth defect and 14 had other conditions. A case-referent analysis was then carried out including 222 children with birth defects and 443 referents. An increased risk was found only for birthmarks, and specifically for hemangiomas, for children with parents exposed to pesticides in the floriculture industry.

Subjective, behavioral and psychophysiological effects of noise.

Abstract: The subjective and psychophysiological responses to noise and the effects of noise on performance have been reviewed in this article. Emphasis was placed on moderate-intensity noise and on the effects relevant for occupational noise exposure. It was concluded that in many respects research presents a rather inconsistent picture of these effects. Still, it is evident that the nonauditory effects of noise may be serious enough to warrant as much general attention in the occupational setting as has for some time been accorded in residential settings.

Otoneurological findings in workers exposed to styrene.

Abstract: An otoneurological test battery was administered to 18 workers with long-term exposure (6-15 years) to styrene at levels well below the current Swedish limit (110 mg/m3). The results were compared with those of a reference group. Disturbances were found in the central auditory pathways of seven workers. Tests reflecting central processing of impulses from different sensory equilibrium organs were abnormal for 16 workers. The most relevant tests seemed to be static posturography and the rotatory visual suppression test. In the posturography the styrene group had a significantly larger sway area than the reference group. In the visual suppression test, the styrene workers displayed a significantly poorer ability to suppress vestibular nystagmus than the reference group. It was concluded that styrene exposure in industrial environments at moderate or low levels causes central nervous system disturbances which are not always diagnosable with psychometric tests but can be apparent in special otoneurological tests.

Lung cancer and exposure to diesel exhaust among bus garage workers.

Abstract: Mortality and cancer incidence was investigated among the 695 bus garage workers employed as mechanics, servicemen, or hostlers for at least six months in five bus garages in Stockholm between 1945 and 1970. The exposure to diesel exhaust and asbestos was estimated by industrial hygienists. A small excess of lung cancer mortality was found in the cohort when occupationally active men in Stockholm were used as the reference group. A case-referent study was performed within the cohort, six referents being selected for each of the 20 lung cancer cases. The lung cancer risk increased with increasing cumulative exposure to diesel exhaust, but not with cumulative asbestos exposure. The relative risk for lung cancer among the highly exposed men was 2.4 (95% CI 1.3-4.5) as compared with those with low exposure. The study indicates that exposure to diesel exhaust increases the risk for lung cancer.

Thermal stress and human performance.

Abstract: There is evidence that the thermal stress encountered in many work environments may negatively affect various aspects of human performance and behavior. Evaluation of the empirical research is, however, complicated by differences in both the methodology and the definition of the basic stimulus. Effects of heat and cold stress are briefly reviewed, with particular regard to theoretical considerations.

Primary liver cancer among women in laundry and dry-cleaning work in Denmark.

Abstract: Tetrachloroethylene has been the most commonly used solvent in dry cleaning in Denmark since the late 1950s. A cohort of laundry and dry-cleaning workers was identified from the Danish Occupational Cancer Register for the study of cancer incidence of persons exposed to tetrachloroethylene. The Register includes cancer incidence data for a 10-year period for 8567 women and 2033 men employed in laundry and dry-cleaning in 1970. A significant excess risk was found for primary liver cancer among the women, with 7 observed and 2.1 expected cases (standardized incidence ratio 3.4, 95% confidence interval 1.4-7.0). No case of primary liver cancer was observed among the men, for whom the expected value was 1.1. The excess risk of primary liver cancer among the women is unlikely to be explained exclusively by excess alcohol consumption.

Occupational cancer in Denmark. Cancer incidence in the 1970 census population.

Abstract: Data sources and creation of data files. The cohort of persons who were 20-64 years of age at the time of the 1970 census has been followed for cancer incidence for a ten-year period. The study was made by linkage of individual records from the 1970 census, the Central Population Register, death certificates, and cancer registrations. Data were included on individual characteristics recorded in the census on prevalent cancer cases at the time of the census and on deaths, emigrations, and incident cancer cases during the ten-year follow-up period. The study includes a total of 2.8 million persons, of whom 2.0 million were economically active at the time of the 1970 census. A total of 115,000 incident cancer cases were registered during the follow-up period, and 77,000 of these occurred in persons who were economically active in 1970. The classifications used in the census included 218 codes for occupation and 245 codes for industry. The Cancer Registry data included 639 codes for diagnosis. Cancer incidence by social groups in Denmark. The cancer incidence was tabulated across 32 socioeconomic groups for 43 cancer sites among the men and 45 cancer sites among the women. The study showed an almost twofold difference in the overall cancer incidence between the socioeconomic groups of the men. Self-employed farmers were at low risk (RR 0.68), and unskilled workers in shipping/fishing were at high risk (RR 1.28) when the cancer incidence among all economically active men was used for the comparison. The social pattern in cancer incidence correlated well with the pattern for cancer mortality among men. As a rough estimate, the cumulative incidence for all cancer among persons under 75 years of age could be reduced by 32% if all Danish men had the cancer incidence of farmers. There was a fivefold or larger difference between the socioeconomic groups in the incidence for nine cancer sites. These nine cancer sites together represented 7% of the cumulative incidence for all cancer. Estimated in a similar way, the cumulative incidence could be reduced by 44% if all Danish men had the site-specific cancer incidence of the respective low-risk groups. The overall cancer incidence among the women varied from a relative risk of 0.71 for unskilled workers in agriculture to a relative risk of 1.18 for self-employed women in other industries I (dentists, lawyers, etc) when the cancer incidence among all economically active women was used for the comparison.(ABSTRACT TRUNCATED AT 400 WORDS)

Combined effect of silica dust exposure and tobacco smoking on the prevalence of respiratory impairments among gold miners.

Abstract: The combined effect of underground gold mining dust with a high content of free silica and tobacco smoking on the prevalence of respiratory impairment was examined among 2209 South African gold miners and 483 nonminers. The subjects were grouped as having normal function; minimal, moderate or marked obstruction; marked obstruction with restriction; or pure restriction on the basis of their lung function profiles. Each profile group was compared with the normal group for exposure prevalences, and additive and multiplicative relative risk models were applied to test for departure from the additivity of individual effects. Departure from additivity was found to increase progressively with the severity of obstructive impairment. The results indicated that approximately 94% of the cases with the most severe respiratory impairment (N = 191) could have been prevented through the elimination of tobacco smoking. In conclusion, tobacco smoking was found to potentiate the effect of dust on respiratory impairments.

Chronic perceived work stress and blood pressure among Australian government employees.

Abstract: Prospective data on 2634 Australian government employees over five years were examined for the effects of chronic perceived work stress on blood pressure change. The study sample (2100 men and 534 women) represented 57% of the original volunteers, or 75% of those eligible after exclusion criteria were met. Data on perceived stress were obtained by questionnaire, and a principal component analysis produced six components: qualitative demands, quantitative demands, job control, future control, work support, and outside stress. Multiple linear regression, which controlled for determinants of blood pressure, tested the main effects and specific two-way interaction effects of the chronicity scores of the six components and 30 items. Many items but only some components were associated with blood pressure change. Sex and age differences were observed. The observed interactions between job demands and control provided equivocal support for the Karasek job-strain model. The women responded to work-based support, but not necessarily as predicted.

Effects of parental occupational exposures on spontaneous abortion and congenital malformation.

Abstract: Human reproduction is a complex process and can be disturbed in many phases by both host and environmental factors. Therefore, it has been difficult to distinguish the occupational causes of spontaneous abortion and congenital malformations from other factors related to the parents' characteristics and their living environment. The extrapolation of results of animal studies to humans is often complicated because there are structural and functional differences between the species and the mechanisms of harmful effects are seldom known. There is also a lack of conclusive epidemiologic studies on the topic. At present knowledge on the potential reproductive toxicity of even rather common occupational exposures is limited and in many cases only suggestive. Paternal exposure to organic solvents before conception and maternal exposure during pregnancy may have adverse effects on the pregnancy and offspring. Heavy physical work during pregnancy may increase the risk of spontaneous abortion.

Interpretation of "negative" studies in occupational epidemiology.

Abstract: Two criteria for an interpretation of noneffect are that the relative risk estimate be near unity and that the confidence interval be narrow; lack of statistical significance has no bearing on this issue. A further requirement is that the relative risk estimate not be near the null value as an effect of non-differential exposure misclassification, negative confounding, or some other systematic error. Occasionally, when results are unexpected or difficult to accept, studies are "underinterpreted" as negative or inconclusive on the basis of arguments such as "confounding," "crude exposure assessment," or "lack of a known mechanism." The present paper supports the position that these arguments are commonly invalid. Scientific standards should be used to separate causal associations from noncausal ones, but in public health decisions this practice has to be balanced by the principle that the "benefit of the doubt" should be given to the persons subject to potential risk.

Respiratory symptoms and lung function of aluminum potroom workers.

Abstract: The association of occupational exposure with respiratory disease and lung function was examined in a cross-sectional study of 1805 aluminum potroom workers. Work-related asthmatic symptoms occurred in 15% of the workers with an exposure of 10 years or more and in 8% of the workers who had been employed less than five years. In a multiple logistic regression analysis an odds ratio (OR) of 3.4 [95% confidence interval (95% CI) 2.1-5.8] for work-related asthmatic symptoms was estimated for long versus short duration of employment. Airflow limitation was also significantly related to years of exposure (OR 2.6, 95% CI 1.7-3.9). Current occupational exposure and the occurrence of respiratory symptoms were not significantly associated. The results suggest that exposure to air pollutants in the primary aluminum industry may lead to the development of asthmatic symptoms, as well as to reduced respiratory function.

Detection of Adducts of Deoxyribonucleic Acid in White Blood Cells of Roofers by 32P-postlabeling Relationship of Adduct Levels to Measures of Exposure to Polycyclic Aromatic Hydrocarbons

Abstract: To assess the utility of adducts of deoxyribonucleic acid (DNA) as biomarkers of exposure to carcinogens in an industrial population, a pilot study of roofers occupationally exposed to polycyclic aromatic hydrocarbons was conducted. DNA isolated from white blood cells of roofers and nonoccupationally exposed comparison subjects matched for age, sex, and smoking status was analyzed for DNA adducts with the use of 32P-postlabeling methods. Occupational exposures to polycyclic aromatic hydrocarbons were assessed by personal air sampling and skin wipes. Ten of the 12 roofers, but only 2 of the 12 comparison subjects, had detectable levels of aromatic DNA adducts in the 32P-postlabeling assay. Among the roofers, the post-shift levels of polycyclic aromatic hydrocarbons in the skin wipes were correlated with the DNA adduct levels. These results suggest that 32P-postlabeling assay may be useful for monitoring internal exposures to complex mixtures of aromatic hydrocarbons in industrial populations.

Fertility among Danish male welders.

Abstract: Welding may be detrimental to the male reproductive system. Fertility was examined in a Danish cohort of 3702 male metalworkers over a follow-up of 47 674 person-years. Occupational histories were gathered by postal questionnaires. Information on births was obtained by record linkage to the Danish Central Population Register. Among persons who had ever worked as welders, the probability of having a child was slightly reduced the year after a year of welding exposure, even after control for differences in age, birth cohort, paternal parity, birth of a child in the preceding five years, smoking, and consumption of alcoholic beverages (odds ratio 0.89, 95% confidence interval 0.83-0.97). The reduction in fertility was associated with the welding of mild steel, but not with the welding of stainless steel. These findings are consistent with results of previous studies of time to conception and semen quality in welders.

Low birthweight, congenital malformations, and spontaneous abortions among dry-cleaning workers in Scandinavia

Abstract: With a common study protocol, case-referent studies within cohorts were performed in Denmark, Norway, Sweden, and Finland to study reproductive hazards of women doing dry-cleaning work. Due to national differences not all of the studies could follow exactly the same procedures in data collection, but they were all based on the linkage of cohorts of dry-cleaning and laundry workers to national registers of births and reproductive failures. Summary measures from each study were combined without the data being pooled. The most significant finding was an increased risk of spontaneous abortion among the most exposed women in the Finnish data. This finding was only supported by the results of the other studies to a minor degree, and the combined odds ratio had confidence limits which included unity.

Validity of exposure data obtained by questionnaire. Two examples from occupational reproductive studies.

Abstract: Exposure data from self-administered questionnaires were compared with independent information on occupational exposures in two studies of reproductive outcome. Agreement in the case-referent study concerning dry-cleaning work and tetrachloroethylene exposure was good. However, exposure reporting was indicated to be more accurate for the cases than the referents. Correction for misclassification slightly changed the odds ratio from 1.02 to 1.27 for nonspecific exposure and from 0.92 to 0.82 for tetrachloroethylene exposure. Missing information on the latter exposure was more crucial, since adding the employer information for such exposure increased the risk estimate to 1.24. In a prospective follow-up study, exposure information was validated in a sample of the study population. Reporting of heavy lifting appeared to be fairly correct, whereas the underreporting of chemical exposures was a problem. Validation of self-reported exposure data is desirable, and the direction and magnitude of possible misclassification bias should be evaluated in each specific situation.

Ethylenethiourea in air and in urine as an indicator of exposure to ethylenebisdithiocarbamate fungicides.

Abstract: Ethylenethiourea (ETU) is a ubiquitous impurity of the ethylenebisdithiocarbamate (EBDC) fungicides widely used in agriculture and forestry. In the present study, ETU was used as a measure of the exposure to EBDC on potato farms and in pine nurseries during the application of EBDC fungicides and the weeding of the sprayed vegetation. Biological and hygienic monitoring was carried out through the analysis of ETU in the breathing zone and the urine of exposed workers. Even if the concentrations of ETU in the ambient air of pine nurseries exceeded those of potato farms, the concentrations of ETU in the urine of potato farmers exceeded those of pine nursery workers. This result may have been due better protective equipment in the pine nurseries. The excretion rate was 6-10 ng/h during the first 60 h after the cessation of exposure, and it diminished thereafter to 0.2 ng/h over a 22-d observation period.

Mortality of cellulose fiber production workers.

Abstract: Mortality was studied among 1271 employees of a cellulose fiber production plant in Rock Hill, South Carolina, in the United States. Each subject was employed for at least three months between 1 January 1954 and 1 January 1977 in jobs that entailed exposure to the highest concentrations of methylene chloride. In the cohort 122 deaths were identified through 1 September 1986, and mortality rates for the cohort were compared with mortality rates for York County, South Carolina. Deficit mortality was observed for cancers of the respiratory system, breast, and pancreas and from ischemic heart disease. Excess mortality was observed for cancers of the buccal cavity and pharynx and the liver and biliary tract, and for melanoma as well. The largest relative excess was for liver and biliary tract cancers. There were only four deaths in this category; however, three of the four deaths were cancer of the biliary tract (3 observed, 0.15 expected, standardized mortality ratio 20).

Postlabeling and immunoassay analysis of polycyclic aromatic hydrocarbons--adducts of deoxyribonucleic acid in white blood cells of foundry workers.

Abstract: Blood samples were obtained from volunteers who were occupationally exposed to polycyclic aromatic hydrocarbons in a Finnish iron foundry and from referents not known to be occupationally exposed to this class of chemical carcinogens. Aromatic adducts were determined in the deoxyribonucleic acid of white blood cells from the exposed workers with the 32P-postlabeling and immunologic techniques. There was a correlation between the estimated exposure in a particular job and the adduct levels. Jobs of men with high adduct levels (greater than 1 adduct/10(7) nucleotides in the postlabeling assay) included sand preparation, molding, shake-out, and transport. The adduct levels were low in men in pattern making, melting, and fettling. This study suggests that 32P-postlabeling and immunoassay may be useful in monitoring human exposure to known and previously unidentified environmental genotoxic agents.

Mortality of workers in the British cotton industry in 1968-1984.

Abstract: The mortality of 3458 cotton industry workers originally enrolled in a study of respiratory symptoms in the period 1968-1970 was followed to the end of 1984. Both the total mortality and the mortality from respiratory disease were less than expected, and they both decreased as length of service increased. However, for the subjects who initially reported byssinotic symptoms, the mortality from respiratory disease was slightly raised overall, and it increased with length of service. These patterns of mortality indicate a survivor effect (ie, a tendency for those with respiratory weakness to leave the industry), together with a long-term effect reflected in respiratory mortality on the health of those workers susceptible to the effects of cotton dust. The mortality from lung cancer was lower than expected, and it decreased with length of service. This finding is consistent with other observations that exposure to cotton dust may reduce the risk of lung cancer.

Perception of effort in manual materials handling.

Abstract: Measurement of subjective work load has emerged as a central topic of interest in the study of physical work and effort. From the practical point of view, subjective estimates of physical effort can contribute greatly to the assessment of work loads in physical activities and to the design of manual handling tasks. The rationale of this approach is that subjective estimates reflect the individual perception of the amount of physical and motivational resources that the subjects invest to meet the demand imposed by the physical task. The present paper provides an illustration of some of the techniques used in measuring the perception of physical effort and reviews and discusses the main results obtained with these techniques in the assessment of manual materials handling.