Dysregulation of Autonomic Control of Cardiac Function in Workers at am Broadcasting Stations (0.738–1.503 MHz)

Description of a large-scale study design to assess work-stress-disease associations for cardiovascular disease

We claim that a new level of studies is needed to answer a series of important questions about the expanding global chronic disease burden for cardiovascular disease (CVD) and for related conditions such as diabetes, metabolic syndrome, and obesity. These require a new study design structure, related to a new level of theory that goes beyond the current single-factor, a-theoretic epidemiological studies. This new platform for the design of large-scale Work/Stress/Disease studies would assess CVD-related disease mechanisms in a more general and dynamic form, based on the use of new tools for measuring autonomic functions in an occupational stress context and a new theory of disease causation. A sample outline is presented for such a study, based on Stress-Disequilibrium Theory (SDT) hypotheses, building on analytic tools developed for the assessment of stress-related exhaustion effects and chronic disease risks from Heart Rate Variability (HRV) research studies. The goal is to assess the associations between social organizational risks, particularly at work, and hypertension, metabolic syndrome, and diabetes II. The study design is multi-stage, spanning across several levels of disease-related de-regulation, and addressing co-morbidity of the conditions themselves. The study design is meant to span across a broad social population at all levels and would probably be multi-site, involving several countries, to yield the larger sample increased power for finding associations for work - physiological effects.

Comparison of cardiac response to managerial workload between men and women

The aim of the study, was to estimate the reaction of selected circulatory system parameters to psychic workload in industrial managers and to answer the question whether may affect this reaction. The study was performed in 23 men (mean 46 +/- 6 years of age) and 16 women (mean 42 +/- 6 years of age), employed as executives in a large industrial plant. The subjects had their 24-h ECG recorded using Medilog 3000 (Oxford). The ECG recordings were classified as pathological according to the standards of Bjerregaard. Heart rate was calculated for working time, leisure time and sleep. The subjects were also asked to estimate the perceived psychic load according to a method involving subjective estimation of work-demands and of an ability to cope with them. Generally, the subjects reported high work demands, but coping abilities were higher than work demands. Both in the men and women, a relationship was found between the intensity of subjective estimation of psychic load and heart rate response. However, the reaction of the circulatory system to the psychic workload in men was long-lasting (its effects continued until late at night); in women it was more direct (only during work). The frequency of abnormalities in 24-h Holter ECG recordings for both test groups was not very high, a little higher in men (30%) than in women (25%), and was comparable with the frequencies in selected general population groups. Our results may indicate that mental workload of the managerial staff, does not cause increased frequency of ECG abnormalities. However, in view of the fact that cardiovascular diseases are more frequent among men than among women, different reaction of the circulatory system to workload should also be accounted for in an attempt to explain the sources of that phenomenon.

Ambulatory ECG monitoring in workers exposed to electromagnetic fields

The aim of this study was to evaluate the function of the circulatory system in workers occupationally exposed to medium frequency electromagnetic fields. The subjects were 71 workers at four AM broadcast stations [0.738-1.503 MHz] aged 20-68 (mean 46.9 +/- 13.1) years and 22 workers at radio link stations aged 23-67 (mean 48.2 +/- 17.4) years. Workers at AM broadcast stations experienced 2-40 (mean 18.6 +/- 12.1) years' exposure to electromagnetic fields (average daily exposure dose about 115 Vh m-1, maximum exposure levels during shift about 165 V m-1), workers at radio link stations had no history of regular exposure to electromagnetic fields. In all the subjects a general medical examination, resting ECG and 24 h Holter monitoring were performed. The work organization, work period structure, age, lifestyle, nutritional habits and health status in both groups remained fairly similar. The electrocardiographic abnormalities detected in the resting and/ or 24 h ECG were significantly more frequent (p = 0.006) in workers exposed to electromagnetic fields than in non-exposed subjects (75% versus 25%). A clear tendency for a higher number of rhythm disturbances (mostly ExV) was observed in AM broadcast station workers.