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Biomedical subjects

B Knave

Publications and source records attributed to B Knave.

At least 19 recordsLinked to original sources
PubMed2001

Working life across cultures: "Work Life 2000: Quality in Work" and occupational health education in developing countries.

The article reflects on the changing world of work, and the challenges presented to both occupational health and occupational health education. We draw on the 63 preparatory workshops and the international conference in the "Work Life 2000: Quality in Work" program, an initiative of the Swedish Presidency of the European Union. The International Commission on Occupational Health is introduced, with particular concentration on a current practical project initiated by the Department of Health in South Africa, intended to lead to a set of projects, networking for occupational health education in developing countries. The practical initiatives cast light on a new set of issues which arise when occupational health and safety crosses cultural barriers, and previously separate comparative cases are linked.

Culture↗
PubMed2001

Electromagnetic fields and health outcomes.

Over the past two decades, there has been increasing interest in the biological effects and possible health outcomes of weak, low-frequency electric and magnetic fields. Epidemiological studies on magnetic fields and cancer, reproduction and neurobehavioural reactions have been presented. More recently, neurological, degenerative and heart diseases have also been reported to be related to such electromagnetic fields. Furthermore, the increased use of mobile phones worldwide has focussed interest on the possible effects of radiofrequency fields of higher frequencies. In this paper, a summary is given on electromagnetic fields and health outcomes and what policy is appropriate--"no restriction to exposure", "prudent avoidance" or "expensive interventions"? The results of research studies have not been unambiguous; studies indicating these fields as being a health hazard have been published and so were studies indicating no risk at all. In "positive" studies, different types of effects have been reported despite the use of the same study design, e.g., in epidemiological cancer studies. There are uncertainties as to exposure characteristics, e.g., magnetic field frequency and exposure intermittence, and not much is known about possible confounding or effect-modifying factors. The few animal cancer studies reported have not given much help in risk assessment; and in spite of a large number of experimental cell studies, no plausible and understandable mechanisms have been presented by which a carcinogenic effect could be explained. Exposure to electromagnetic fields occurs everywhere: in the home, at work, in school, etc. Wherever there are electric wires, electric motors and electronic equipment, electromagnetic fields are created. This is one of the reasons why exposure assessment is difficult. For epidemiologists, the problems is not on the effect side as registers of diseases exist in many countries today. The problem is that epidemiologists do not know the relevant exposure characteristics to be used in their studies. In international guidelines, limits for restrictions of field exposure are several orders of magnitude above what can be measured from overhead power lines and found in "electrical" occupations. These guidelines emphasize that the state of scientific knowledge today does not warrant limiting exposure levels for the public and the work force, and that further data are required to confirm whether health hazards are present. In some countries, however, the "principle of caution" or "prudent avoidance" has been adopted; meaning the low-cost avoidance of unnecessary exposure as long as there is scientific uncertainty about its health effects.

Cardiovascular Diseases↗
PubMed1994

Electric and magnetic fields and health outcomes--an overview.

In recent years interest has increased in the biological effects and possible health outcomes of weak electric and magnetic fields. Studies have been presented on magnetic fields and cancer, reproduction, and neurobehavioral reactions. Epidemiologic studies on childhood leukemia and residential exposure from power lines seem to indicate a slight increase in risk, and excess leukemia and brain tumor risks have been reported in "electrical" occupations. In spite of a large number of experimental laboratory studies, however, no plausible and understandable mechanism has been presented by which a carcinogenic effect could be explained. International guidelines state that the scientific knowledge on magnetic fields and cancer does not warrant limiting exposure levels for the general public and work force down to the low levels of everyday exposure. Study results on reproduction, including adverse pregnancy outcomes, and neurobehavioral disorders are generally considered insufficiently clear and consistent to constitute a scientific basis for restricting exposure.

Adult↗
PubMed1993

Occupational exposure to electromagnetic fields in relation to leukemia and brain tumors: a case-control study in Sweden.

Occupational exposure to low-frequency electromagnetic fields (EMF) was studied in 250 leukemia patients and 261 brain-tumor cases, diagnosed in 1983-87 and compared with a control group of 1,121 randomly selected men, from the mid-region of Sweden, 1983-87. We based the exposure assessment on measurements from 1,015 different workplaces. On the basis of the job held longest during the 10-year period before diagnosis, we found an association between the average, daily, mean level of EMF and chronic lymphocytic leukemia (CLL). The risk increased with increasing level of exposure. The odds ratios (OR) and the 95 percent confidence interval (CI) for three consecutive levels of exposure were: 1.1 (CI = 0.5-2.3); 2.2 (CI = 1.1-4.3); 3.0 (CI = 1.6-5.8), respectively. No association was observed for acute myeloid leukemia (OR = 1.0, CI = 0.5-1.8; OR = 0.8, CI = 0.4-1.6; OR = 1.0, CI = 0.6-1.9). For brain tumors, the corresponding risk estimates were 1.0 (CI = 0.7-1.6); 1.5 (CI = 1.0-2.2); 1.4 (CI = 0.9-2.1). Different EMF indices were tested. Tasks with frequent or large variations between high and low field-densities (high standard deviation) were more common among CLL subjects. For brain tumors, a prolonged high level (high median values) showed the strongest association. Confounding by place of residence, smoking, benzene, ionizing radiation, pesticides, and solvents was evaluated, and these factors did not seem to have a decisive influence on the associations. We also analyzed other potential sources of bias. For CLL, there were indications of an excess number of low-exposure subjects among non-responders, which, to some extent, may have enhanced but not caused the risk estimates obtained. Our conclusion is that the study supports the hypothesis that occupational EMF exposure is a hazard in the development of certain cancers.

Acute Disease↗
PubMed1991

Incidence of work-related disorders and absenteeism as tools in the implementation of work environment improvements: the Sweden Post strategy.

In 1989, a comprehensive, five-year work environment project (Postal Work Environment [PWE] 2000) was launched by Sweden Post (SP). Its purpose was to identify the jobs and employees with the most exposed work environments and, in conjunction herewith, to initiate remedial programmes. Standardized interviews with a selection of employees and statistical and epidemiological evaluation of illness absenteeism and occupational injuries served as input data for devising different measures of work-related ill health (subjective complaints, symptoms, illness, illness absenteeism, and occupational injury). The results provided an incentive to regional action programmes, in which 'risk areas and risk occupations' were correlated with the load factors, primarily in ergonomic and work organization areas, cited in interview replies. In its regional efforts. PWE 2000 served as a stimulus/catalyst in the implementation of various regional action programmes.

Absenteeism↗
PubMed1991

Incidence of leukaemia and brain tumours in some "electrical occupations".

A 19 year follow up study was conducted to explore the association between occupations expected to be exposed to electromagnetic fields and the occurrence of leukaemia and brain tumours. Incidence of cancer between 1961-79 was calculated and the standardised morbidity ratio (SMR) with a 95% confidence interval (95% CI) was related to that of all Swedish working men. For all the selected "electrical occupations" the SMRs for total leukaemia and brain tumours were near unity. Increased risks were noted for all leukaemia among electrical/electronic engineers and technicians, (SMR 1.3; 95% CI 1.0-1.7) as well as in the sub-groups of telegraph/telephone (2.1; 1.1-3.6) and machine (2.6; 1.0-5.8) industries. Risk for chronic lymphoid leukaemia was increased in the same occupational category (1.7; 1.1-2.5) and in the sub-group of machine industry (4.8; 1.0-14.0), as well as for all linesmen (2.0; 1.0-3.5) and power linesmen (2.8; 1.1-5.7). Risk for acute myeloid leukaemia was increased among all miners (2.2; 1.0-4.1) and miners working in iron/ore mines (5.7; 2.1-12.4). Increased risk for all brain tumours (2.9; 1.2-5.9) and glioblastomas (3.4; 1.1-8.0) appeared among assemblers and repairmen in radio and TV industry. Raised risk for all brain tumours was seen for all welders (1.3; 1.0-1.7) and welders in iron/steel works (3.2; 1.0-7.4) and risk for glioblastomas was also increased for all welders (1.5; 1.1-2.1). No major changes in relative risk estimates were noted after the exclusion of persons who were over 65 at the time of diagnosis. Although a homogeneous pattern of increased risks of leukaemia or brain tumour was not noted, the hypothesis that magnetic fields might play a part in the origin of cancer cannot be rejected.

Adult↗
PubMed1988

Exposure to low-frequency electromagnetic fields--a health hazard?

Several epidemiologic studies indicate an association between exposure to low-frequency electromagnetic fields and certain types of cancer. However, there is no solid evidence from current experimental studies to support the hypothesis of carcinogenicity. Further research is needed, and in the present extended abstract Swedish epidemiologic studies projected for the future are briefly outlined. The studies will be time-consuming and will involve high costs. However, we anticipate that within the next four years the approach described will contribute significantly to knowledge about the possible health hazards caused by electromagnetic fields.

Adult↗
PubMed1986

Cancer in the electric power industry.

A cohort study of 3358 power linesmen and 6703 power station operators classified in the 1960 population census in Sweden was undertaken. The cancer incidence between 1961 and 1979 was calculated in relation to all male blue collar workers. The relative risk of cancer (all sites) was 1.1, (1.0-1.2, 90% confidence limit) in the group of power linesmen and 1.0 (0.9-1.0) for power station operators. No consistent excess risk of leukaemia or brain tumour was found in the two occupational groups. In both groups a tendency towards an excess risk of cancer of the urinary organs was found.

Adult↗
PubMed1984

Ergonomics and lighting.

The two main principles of ergonomics can be said to 'fit the job to the man', or 'fit the man to the job'. To a high extent this is really valid for lighting ergonomics. If an employee complains that he (or she) cannot see properly what he is doing in his work it could be adjusted either by improving the job itself or by improving the visual capacity of the person in question (eg, prescribing correct work glasses). If improving measures are not taken local eye discomfort may develop with symptoms as fatigue, ache, pain, burning, pulling, tearing, etc. These symptoms make up a syndrome called asthenopia, otherwise succinctly known as eye strain. The causes of the syndrome can be myriad - but all fall in under the headings 'bad' lighting, 'bad' eyes and 'bad' work.

Journal Article↗
PubMed1984

Glare from outdoor high mast lighting: effects on visual acuity and contrast sensitivity in comparative studies of different floodlighting systems.

Glare effects on visual acuity and contrast sensitivity were studied at outdoor timber terminal work with conventional far-reaching floodlighting and with a new type of oblique floodlighting with an asymmetrical light distribution. The binocular work visual acuity of 19 volunteers was measured at 40, 55 and 80 per cent contrast and the contrast sensitivity of 14 volunteers at spatial frequencies of 0.5, 1, 2, 4, 8 and 16 cycles/degree. With the light source 15 degrees from the centre of the visual fields the visual acuity as well as the contrast sensitivity was consistently lower with the conventional type than the new type of floodlight . The results thus indicate that not only the vision of details is impaired by glare but also the contrast perception of sparse patterns. In standardized rating scales the timber terminal workers scored the difference in glare between the two floodlight systems as "great"--"very great".

Adult↗
PubMed1984

Age and sex distribution of some retinal macular diseases: senile and presenile macular degeneration and central serous retinitis.

The age and sex distribution of senile macular degeneration (SMD) was investigated at the Low Vision Clinic in Stockholm. SMD increased with age and was found to be more common among women than men. This difference was not due to the fact that women live longer than men or related to women consulting ophthalmologists more often than men because of visual handicap. The age and sex distribution of presenile macular degeneration ( PSMD ) and central serous retinitis (CSR) was investigated at the Department of Ophthalmology of Falun Hospital. Also PSMD increased with age and was found to be more common among women than men, even if the sex difference was not as clear as for SMD. CSR was found to be more frequent at younger ages and, contrary to SMD and PSMD , more common among men. The reasons for these sex differences in frequencies of SMD, PSMD and CSR are not known.

Adult↗
PubMed1983

Exposure to and effects of glare from high mast lighting on workers at a timber terminal.

High mast floodlighting at outdoor workplaces has economic advantages but suffers from shortcomings such as glare. This study was made to collect and evaluate data from a situation with glare from a physical and occupational health standpoint. When unloading timber, the worker's gaze is frequently directed upward, whereas conventional glare indexes for luminaires assume the gaze is diagonally downwards. It was found that reduced visual acuity could cause difficulty in normal working routines.

Journal Article↗
PubMed1983

Investigation of visual strain experienced by microscope operators at an electronics plant.

This investigation was concerned with the examination of 75 microscope operators at an electronics plant, with reference to eye function and visual strain. It consisted of three separate parts: (1) standardised interviews dealing with symptoms of visual strain, (2) examinations of the refractive state as well as possible diseases of the eye, and (3) examination of binocular vision. It emerged that 80% of the microscope operators engaged in full time microscope operation experienced various symptoms of visual strain. A statistically verified relationship was found to exist between these manifestations of visual strain on the one hand and uncorrected astigmatism, fusion insufficiency (poorer eye co-ordination) and the length of time spent at the microscope during the working day on the other.

Journal Article↗
PubMed1983

Neuropsychiatric symptoms in workers occupationally exposed to jet fuel--a combined epidemiological and casuistic study.

Some aircraft personel and airline industry workers are exposed to jet fuel, a mixture of aliphatic hydrocarbons (petroleum 80%) and some organic solvents (petroleum 80%) and some organic solvents (aromatic hydrocarbons 20%). In order to evaluate the possible neuropsychiatric sequeale of such long-term occupational exposure, we examined 30 workers exposed at about 250 mg/m3 for 4-32 years at a jet motor factory. They were compared with two control groups (2 x 30) of matched non-exposed workers. The medical history was first assessed by standardized interviews and examination of medical records kept by the factory physician. The exposed subjects had, after their employment, much more often sought medical advice because of emotional dysfunctions, such as depression and anxiety, than had the control groups (P less than 0.005). When the prevalent mental symptoms, indicative of brain lesion, later were rated by psychiatrists, the exposed workers scored higher than did the controls (P less than 0.001). 14 subjects showing most symptoms were then selected for a thorough neuropsychiatric clinical investigation comprising psychosocial inquiries, psychological testing, personality assessment and neurological/neurophysiological examination. Seven were judged to suffer from mild organic brain syndrome (i.e. "organic neurasthenia") of which one subject was a severe case. The subjects had all undergone a slow but steady personality change over the years--starting from an ordinary strength without neurotic traits and moving towards an asthenic state with fatigue, anxiety and vegetative hyperreactivity. No other cause for this change could be identified as an alternative to the occupational exposure to jet fuel. It is concluded that personality changes and emotional dysfunctions are the foremost effects of such long-term exposure to petroleum products.

Adult↗
PubMed1980

Exposure to organic solvents. A cross-sectional epidemiologic investigation on occupationally exposed care and industrial spray painters with special reference to the nervous system.

In the present epidemiologic study 80 car or industrial spray painters with long-term low level exposure to organic solvents were examined and compared with two matched reference groups of nonexposed industrial workers (80 persons in each group). The aim of the study was to investigate the possible effects of the solvent exposure on health. The investigation included psychiatric interviews, psychometric tests, neurological, neurophysiological and ophthalmologic examinations, and computed tomography of the brain. The painters' previous and present exposure was carefully assessed by interviews and on-the-job measurements both at modern places of work and in a reconstructed model of a workshop from 1955. On the basis of the psychiatric interviews the psychiatric symptoms were rated according to a specially designed scale of 46 different items, graded in seven steps of increasing severity. The psychological performance was assessed by a battery of 18 tests. The neurological and neurophysiological examinations comprised visual evoked responses (VER), electroencephalography (EEG), and computerized EEG analysis (SPA) for the central nervous system and electroneurography (ENeG), the estimation of vibration sense thresholds, and a quantified neurological examination for the peripheral nervous system. The ophthamologic examination concentrated on the condition of the lens. Statistically significant differences between the exposed individuals and referents were found for psychiatric items indicative of a slight cerebral lesion (ie, a neurasthenic syndrome). The psychometric tests revealed statistically significant differences between the groups with respect to reaction time, manual dexterity, perceptual speed, and short-term memory. No differences were found with respect to performance on verbal, spatial, and reasoning tests. Significant differences between the groups were also found for the majority of the neurophysiological parameters measuring peripheral nerve functions, the most pronounced occurring in the long, sensory fibers. Moreover EEG and VER showed some differences between the groups, as did the results of the ophthalmologic examination and the computed tomography. Finally, it should be emphasized that the exposure levels, as measured at modern places of work and in the reconstructed workshop from 1955, were found to be considerably lower than the valid threshold limit values in Sweden.

Brain↗
PubMed1979

Neurasthenic symptoms in workers occupationally exposed to jet fuel.

Long-term exposure to petroleum distillation products (e.g. jet fuel) has been suggested to cause chronic mental and neurological symptoms. In the present "cross-sectional epidemiological study" the extent of neuropsychiatric ill-health in 30 workers exposed to jet fuel was compared with that in 60 non-exposed matched controls. Standardized medical interviews showed a higher occurrence of neurasthenic symptoms in exposed subjects (P less than 0.001). The result was confirmed by examination of the medical records kept by the factory physician (P less than 0.01). The prevalence of psychiatric symptoms was assessed with a rating scale of 37 items (a modified CPRS). Again, the exposed workers scored higher than the controls (P less than 0.001), particularly regarding the neurasthenic symptoms, i.e. fatigue, anxiety, mood changes, memory difficulties, and various psychosomatic symptoms (P less than 0.01). The results could neither be explained by observer's bias, nor by a greater susceptibility for mental disorders in the exposed subjects. We therefore conclude that occupational exposure to jet fuel vapours around the present threshold limit values may induce a neurasthenic syndrome.

Adult↗