Cardiovascular mortality and exposure to extremely low frequency magnetic fields: a cohort study of Swiss railway workers

Risk Factors for Heart Disease in Working Railwaymen

Heart diseases are the most common non-communicable diseases worldwide. We examined the prevalence of risk factors for heart disease among a sub-population of working men. In total, 11,059 railway crew workers of the Russian Railways Company were included in the study. We also asked participants to answer several questions based on the WHO STEPwise approach to surveillance (STEPS) translated into Russian. Only 30% of drivers had normal body mass index (BMI), whereas 70% were overweight or obese. In 12% of subjects, total cholesterol was higher than 5 mmol/L. In 15% of participants, glucose level was higher than 5.5 mmol/L. 38% of drivers reported smoking. Physical inactivity was registered in 54% of persons. Only 29% ate according to the key principles of good diet quality. 24% of respondents had a family history of heart disease. MANOVA demonstrated that BMI was determined by age, profession, smoking, physical inactivity, and diet quality. As age increased, the number of people with normal cholesterol levels decreased. It was demonstrated that a correlation existed between glucose levels and BMI. In the total group, the correlation was 0.46 (p < .05). The correlation between those parameters increased due to age, from 0.33 in the <30 years of age group up to 0.52 in the >50 years of age group. This study demonstrated that there is a high prevalence of risk factors for heart disease in train drivers in the Russian Federation.

Risk Factors for Locomotive Crew Members Depending on Their Place of Work

PURPOSE

The purpose of this study is to examine the prevalence of workplace exposure, behavior, and individual health conditions, along with resulting medical activity among locomotive crew members depending on their place of work.

PATIENTS AND METHODS

Participants included 5585 train drivers and 3723 train drivers' assistants (7% of the total train operators in the Russian Federation). Measured height and weight were used to calculate body mass index (BMI), and waist circumference, pulse rate, and blood pressure were also measured. The risk assessment was conducted using the STEPS tool. The level of commitment to a Healthy Lifestyle was assessed based on World Health Organization recommendations. Occupational risk factors were surveyed. Morbidity was analyzed over the past year.

RESULTS

The lowest frequency of work exposure risk factors was found for employees of the Trans-Baikal railway; the highest was among Krasnoyarsk, North, and South-East. The participants from the Far East and October Railways had the lowest self-reported frequency of behavioral risk factors. The participants from the Eastern Siberian, October, and Southern Urals railways had the lowest occurrence of individual health conditions. The participants from the East Siberian, Far East, Kuibyshev, and Sverdlovsk railways were the least likely to visit their doctor, take temporary disability leave, or be hospitalized. The total assessed Healthy Lifestyle commitment index was higher for participants from the Far Eastern and Southern Urals railways. The participants from the Moscow and October railways were the least committed to a Healthy Lifestyle.

CONCLUSIONS

Significant differences exist between risk factors and Healthy Lifestyle commitment between railways. Future research should examine changes due to a new corporate health program introduced in 2020.

Exposure levels of ELF magnetic fields in the residential areas of Mangaung Metropolitan Municipality

The aim of this study was to evaluate the exposure levels of ELF magnetic fields in the residential areas of Mangaung metropolitan municipality. Fifteen residential sites were randomly selected in Bloemfontein, nine in Botshabelo and six in Thaba Nchu areas of Mangaung. Measurements were collected at the distances of 3 m, 6 m and 9 m outside electrical substations, near every corner, using a Trifield meter model XE 100. Measurements were also collected from four different corners inside substations, near barrier screening and were referred to as a distance of 0 m (reference point). The results indicated a non-significant difference among 15 residential areas; BRE1 to BRE15 and six areas; TNRE1 to TRNE6. The exposure levels were significantly high in one residential area BORE1 (0.55 μT) as compared to other residential sites in Botshabelo (p < 0.001). The results obtained from the measurements also show a significant difference between the residential areas BORE4 and BORE8 (p < 0.01) as well as BORE4 and BORE9 (p < 0.006). The four distance interims also demonstrated a highly significant difference (p < 0.0001) when compared to one another. The t test showed a statistically significant difference for exposure levels recorded at 3 m, 6 m and 9 m in comparison to 0 m (p < 0.01). The exposure levels recorded at 3 m were also significantly different to those recorded at 6 m (p < 0.05) and 9 m (p < 0.01). The exposure levels measured at all distances are below the ICNIRP guidelines and the fields decrease rapidly with an increased distance from the source.

Eotaxin‑1 and MCP‑1 serve as circulating indicators in response to power frequency electromagnetic field exposure in mice

The increasing public concern regarding the potential health risks of exposure to electromagnetic fields (EMFs) has led to intensive research in this area. However, it remains unclear whether potential pro-oncogenic effects may be caused by power frequency EMF (PFEMF) exposure. To address the associated risk factors, the present study exposed 4-week old Balb/c mice to 0, 0.1, 0.5 and 2.5 mT of constant 50 Hz Helmholtz coil-type PFEMF for 90 days to explore the circulating chemokine indicators that may be associated with inflammation or cancer. No measurable weight difference existed between the control and PFEMF-exposure groups; however, the Luminex assay clearly demonstrated differentially responsive profiles of circulating chemokines upon PFEMF treatment. Monocyte chemoattractant protein (MCP)-3, macrophage inflammatory protein (MIP)-1α, MIP-1β and MIP-2 levels in serum were not significantly altered by PFEMF during the 3-month exposure period; however, the circulating levels of other chemokines including IP-10, GROα, RANTES, EOTAXIN-1 and MCP-1 exhibited significant changes upon treatment. Among the responsive chemokines, EOTAXIN-1 and MCP-1 were significantly increased by 0.5 mT of PFEMF treatment, which may support their use as indicators of PFEMF exposure. This novel finding highlights the potential pro-inflammatory nature of power frequency, which may shed light on the mechanisms underlying PFEMF-induced diseases, including cancer.

DYNAMICS OF CARDIOVASCULAR RISK FACTORS IN RAILWAY CREWS

Aim. To assess the prevalence of cardiovascular risk factors (RF) and dynamics over 4 years in locomotory crews.

Material and methods. One hundred train drivers and assistants aged 25-59 y.o. (mean age — 43,8±10,3 y.) were investigated in-patient with 24 hour blood pressure (BP) monitoring, ultrasound Doppler of brachiocephalic arteries, standard biochemistry. Fifty three persons were assessed prospectively from 2013 to 2017 y.

Results. BP increase (essential hypertension of I-II grades with mild or moderate hypertension) was found in 78 persons, with the mean duration — 10,4±4,3 years, and age of onset — 37,0±8,5 y.o. Most commonly, the dyslipidemiaswerefound:hypertriglyceridemiain59%,hypercholesterolemia in 44%. Smokers — 39%, overweight — 37%, obese — 41%. Correlational analysis revealed significant direct correlation of triglycerides with body mass index (r=0,35), with glucose tolerance disorder (r=0,22) and hypertension (r=0,22), however there was negative correlation with smoking status (r=-0,25). In patients with hypertension, aged 25-39 (n=18), comparing to the group with the none (n=22), there were significantly higher: body mass index, cholesterol level, triglycerides level and low density lipoproteideslevelwiththeabsenceofdifferenceinhighdensitylipoproteides, smoking prevalence and family anamnesis of cardiovascular diseases. In prospective follow-up the negative dynamics of lipid profile was found in males of 25-39 y.o., and morphological presentation — lesions in brachiocephalic arteries, at the age 40-49 y. with stabilization of parameters at the age 50-59 y.o. Mean group levels of systolic and diastolic BP at daytime and at night in both timepoints were within normotension range in all groups, corresponding to “non-dipper” type.

Conclusion. Most prevalent RF in railway crews were dyslipidemia and obesity. The adequacy of therapy prescribed in all age strata makes it to regard the raise of BP as modifiable RF.

Exosomal small RNA sequencing uncovers the microRNA dose markers for power frequency electromagnetic field exposure

PURPOSE

The potential health risks caused by power frequency electromagnetic field (PFEMF) have led to increase public health concerns. However, the diagnosis and prognosis remain challenging in determination of exact dose of PFEMF exposure.

MATERIALS AND METHODS

Mice were exposed to different magnetic doses of PFEMF for the following isolation of serum exosomes, microRNAs (miRNAs) extraction and small RNA sequencing. After small RNA sequencing, bioinformatic analysis, quantitative real-time PCR (qRT-PCR) validation and serum exosomal miRNA biomarkers were determined.

RESULTS

Significantly changed serum exosomal miRNA as biomarkers of 0.1, 0.5, 2.5 mT and common PFEMF exposure were confirmed. Gene ontology (GO) and Kyoto encyclopaedia of genes and genomes (KEGG) pathway analysis of the downstream target genes of the above-identified exosomal miRNA markers indicated that, exosomal miRNA markers were predicted to be involved in critical pathophysiological processes of neural system and cancer- or other disease-related signalling pathways.

CONCLUSIONS

Aberrantly-expressed serum exosomal miRNAs, including miR-128-3p for 0.1 mT, miR-133a-3p for 0.5 mT, miR-142a-5p for 2.5 mT, miR-218-5p and miR-199a-3p for common PFEMF exposure, suggested a series of informative markers for not only identifying the exact dose of PFEMF exposure, also consolidating the base for future clinical intervention.

The effects of 50 Hz magnetic field exposure on DNA damage and cellular functions in various neurogenic cells

Epidemiological studies have indicated a possible association between extremely low-frequency magnetic field (ELF-MF) exposure and the risk of nervous system diseases. However, laboratory studies have not provided consistent results for clarifying this association, despite many years of studies. In this study, we have systematically investigated the effects of 50 Hz MF exposure on DNA damage and cellular functions in both neurogenic tumor cell lines (U251, A172, SH-SY5Y) and primary cultured neurogenic cells from rats (astrocytes, microglia, cortical neurons). The results showed that exposure to a 50 Hz MF at 2.0 mT for up to 24 h did not influence γH2AX foci formation (an early marker of DNA double-strand breaks) in any of six different neurogenic cells. Exposure to a 50 Hz MF did not affect cell cycle progression, cell proliferation or cell viability in neurogenic tumor U251, A172 or SH-SY5Y cells. Furthermore, the MF exposure for 24 h did not significantly affect the secretion of cytokines (TNF-α, IL-6 or IL-1β) in astrocytes or microglia, or the phagocytic activity of microglia. In addition, MF exposure for 1 h per day did not significantly influence expression levels of microtubule-associated protein tau, microtubule-associated protein 2, postsynaptic density 95 or gephyrin in cortical neurons, indicating an absence of effects of MF exposure on the development of cortical neurons. In conclusion, our data suggest that exposure to a 50 Hz MF at 2.0 mT did not elicit DNA damage effects or abnormal cellular functions in the neurogenic cells studied.

Occupational factors and a risk of cardiovascular diseases

The paper gives Russian and foreign authors’ data on a relationship between occupational factors and cardiovascular diseases. It considers the impact of psychosocial stress on the risk of hypertension, coronary heart disease, and cardiovascular events in representatives of different professional groups.

The effect of electromagnetic radiation emitted by display screens on cell oxygen metabolism - in vitro studies

INTRODUCTION

Research studies carried out for decades have not solved the problem of the effect of electromagnetic radiation of various frequency and strength on the human organism. Due to this fact, we decided to investigate the changes taking place in human blood platelets under the effect of electromagnetic radiation (EMR) emitted by LCD monitors.

MATERIAL AND METHODS

The changes of selected parameters of oxygen metabolism were measured, i.e. reactive oxygen species concentration, enzymatic activity of antioxidant defence proteins - superoxide dismutase (SOD-1) and catalase (CAT) - and malondialdehyde concentration (MDA). A suspension of human blood platelets was exposed to electromagnetic radiation of 1 kHz frequency and 150 V/m and 220 V/m intensity for 30 and 60 min. The level of changes of the selected parameters of oxidative stress was determined after the exposure and compared to the control samples (not exposed).

RESULTS

The measurements revealed an increase of the concentration of reactive oxygen species. The largest increase of ROS concentration vs. the control sample was observed after exposure to EMF of 220 V/m intensity for 60 min (from x = 54.64 to x = 72.92). The measurement of MDA concentration demonstrated a statistically significant increase after 30-min exposure to an EMF of 220 V/m intensity in relation to the initial values (from x = 3.18 to x = 4.41). The enzymatic activity of SOD-1 decreased after exposure (the most prominent change was observed after 60-min and 220 V/m intensity from x = 3556.41 to x = 1084.83). The most significant change in activity of catalase was observed after 60 min and 220 v/m exposure (from x = 6.28 to x = 4.15).

CONCLUSIONS

The findings indicate that exposure to electromagnetic radiation of 1 kHz frequency and 150 V/m and 220 V/m intensity may cause adverse effects within blood platelets' oxygen metabolism and thus may lead to physiological dysfunction of the organism.

Health Implications of Electromagnetic Fields, Mechanisms of Action, and Research Needs

Electromagnetic fields (EMF) have been implicated to influence a range of bodily functions. Given their ubiquitous nature, widespread applications, and capability to produce deleterious effects, conclusive investigations of the health risks are critical. Accordingly, this paper has been constructed to weigh the bioeffects, possible biointeraction mechanisms, and research areas in bioelectromagnetics seeking immediate attention. The several gaps in the existing knowledge do not permit one to reach a concrete conclusion but possibility for harmful effects cannot be underestimated in absence of consistent findings and causal mechanisms. Several studies with appropriate methodologies reflect the capacity of electromagnetic radiations to cause adverse health effects and there are several credible mechanisms that can account for the observed effects. Hence, need of the hour is to activate comprehensive well-coordinated blind scientific investigations, overcoming all limitations and demerits of previous investigations especially replication studies to concretize the earlier findings. Furthermore, appropriate exposure assessment is crucial for identification of dose-response relation if any, and the elucidation of biological interaction mechanism. For the time being, the public should follow the precautionary principle and limit their exposure as much as possible.