Selected Exogenous (Occupational and Environmental) Risk Factors for Cardiovascular Diseases in Military and Aviation.

Cardiovascular diseases are a group of disorders of heart and blood vessels which are the leading cause of death globally. They are also a very important cause of military unsuitability especially among military pilots. Some of the risk factors cannot be modified, but a large group of them can be modified by introducing healthy habits or behaviors, such as regular physical activity, quitting of tobacco smoking, cessation of harmful alcohol consumption, or stress avoidance. Specific occupational and environmental factors, such as acceleration, pressure changes, hypoxia, thermal stress, noise, vibration, prolonged sedentary posture, difficulties in moving the limbs, shifts, work shift irregularities, circadian dysrhythmia, variations in the microclimate, motion sickness, radiation, toxicological threats, occupational stress, emotional tension, highly demanding tasks especially during take-off and landing, predominance of intellectual over physical activity, and forced operation speed against time shortage are considered as characteristic for military personnel, especially military aircrews. They are of special concern as some of them are considered as potential CVD risk factors. The aim of this study was to discuss the influence of selected occupational and environmental factors (noise, altitude, hypoxia, acceleration forces, tobacco smoking, oral health, and stress) regarding their importance for CVD risk in military professionals and military aviators. The performed revision confirmed that they are exposed to certain characteristic conditions, which may influence the CVD risk but the number of solid scientific data regarding this subject are limited. There is a great need to perform complex studies on environmental and occupational risk factors for CVDs in military personnel and military aviators as well as how to minimize their influence to prolong the state of health and military suitability of this professional groups.

Endogenous Risk Factors of Cardiovascular Diseases (CVDs) in Military Professionals with a Special Emphasis on Military Pilots.

Cardiovascular disease (CVD) risk factors can be categorized as non-modifiable and modifiable. Modifiable risk factors include some exogenous and behavioral factors that can be easily modified, whereas endogenous modifiable risk factors, such as hypertension, hyperlipidemia, diabetes, or obesity may be modified to a limited extend. An increased prevalence of CVDs as well as their risk factors have been observed in military personnel, as specific military-related stressors are highly correlated with acute cardiac disorders. Military pilots are a subpopulation with great CVD risk due to an accumulation of different psychological and physical stressors also considered to be CVD risk factors. This review presents data concerning CVD risk in military professionals, with a special emphasis on military pilots and crew members. We also discuss the usefulness of novel indicators related to oxidative stress, inflammation, or hormonal status as well as genetic factors as markers of CVD risk. For a correct and early estimation of CVD risk in asymptomatic soldiers, especially if no environmental risk factors coexist, the scope of performed tests should be increased with novel biomarkers. An indication of risk group among military professional, especially military pilots, enables the implementation the early preventive activities, which will prolong their state of health and military suitability.

Assessment of Risk Factors for Development of Overweight and Obesity among Soldiers of Polish Armed Forces Participating in the National Health Programme 2016-2020.

The aim of this study was to assess the prevalence of overweight and obesity among Polish Armed Forces soldiers and to analyze risk factors impacting body mass. In total, 1096 male, Caucasian soldiers (36.31 ± 8.03 years) participated in this study. Anthropometric data were obtained, and questionnaires evaluated sociodemographic, environmental, behavioral and biological factors known to be associated with obesity. Only 33% of the total number of participants had normal body weight, and 17.3% were considered obese (according to WHO criteria). The results showed that being 40 years or older, sleeping six hours or less per day, more frequent reaching for food in stressful situations, having a mother with excessive body weight, not exercising or exercising at most two days per week, and spending two hours a day or more in front of the TV increase the risk of obesity. Taken together, the results show that factors such as family history of obesity, dietary habits, physical activity, length of sleep and ability to cope with stress could be used to identify soldiers at higher risk of developing obesity in order to provide them with personalized prevention programs.

Association of Interleukin Genes IL10 and IL10RB with Parameters of Overweight in Military Students.

BACKGROUND: To date, nearly 300 single-nucleotide polymorphisms (SNPs) associated with BMI, waist-to-hip ratio, and other adiposity traits have been identified by GWAS. With regards to IL10, at least 49 IL10-associated polymorphisms have been reported. However, little is known regarding the relationship between SNPs of the IL10 gene and the risk of obesity in young men. The aim of the present study was to investigate the relationship between SNPs of the IL10 and IL10RB genes and the risk of obesity in young men. METHODS: A cohort of 139 male students were enrolled and the following IL10 and IL10RB SNPs were analyzed: IL10 (rs1518110), IL10 (rs3024491), IL10RB (rs2834167). The subjects were divided into groups depending on obesity parameters: body mass index (BMI), fat mass index (FMI) and fat percentage (Fat%). Statistical analysis was conducted for a single locus and haplotypes, an association between SNPs and body composition parameters was tested with four genetic models: dominant, recessive, codominant and overdominant mode of inheritance (MOI). RESULTS: Significant association was found for interaction IL10 (rs1518110) × IL10RB (rs2834167) with Fat% value exceeding 20 in codominant (p-value = 0.03, OR = 0.34, 95% CI 0.08 1.44) and dominant model (p-value = 0.03, OR = 0.34, 95% CI 0.08 1.44) Conclusion: Our study shows for the first time that there is a correlation between the occurrence of specific polymorphisms of IL10 gene (rs1518110, rs3024491 and rs2834167) and the possibility of obesity.

The interactions between interleukin-1 family genes: IL1A, IL1B, IL1RN, and obesity parameters.

BACKGROUND: Obesity has been recognized as a worldwide growing problem, producing many pathologies including the promotion of "proinflammatory state." The etiology of human obesity is still only partially understood; however, the genetic background has been proved. Its nature is complex, and currently, it appears that the combined effects of the interactions among multiple genes should receive more attention. Due to the fact that obesity promotes proinflammatory conditions, in this study, we investigated the genetic polymorphism of IL-1 family genes in healthy people with normal and elevated body mass index (BMI) and fat %. RESULTS: The single-nucleotide polymorphisms (SNPs) within the IL1A -889C > T (rs1800587), IL1B + 3954 T > C (rs1143634), and IL1RN -87G > A (rs2234677) genes alone were associated neither with BMI nor fat % values in tested group. The associations between SNP-SNP interaction and BMI for the IL1B × IL1RN interactions were significant for dominant model (p = 0.02) and codominant model (p = 0.03). The same SNP-SNP interaction (IL1B × IL1RN) was associated also with fat % for codominant (p = 0.01) and recessive (p = 0.002) models. CONCLUSIONS: This study further confirmed that IL-1 family genes are involved in genetic background of obesity. It has been shown that interaction IL1B × IL1RN was associated with both BMI and fat % with rare T allele protecting form higher values. Thus, even if certain polymorphisms in single genes of IL-1 family cannot be defined as related to obesity in examined population, the genetic interrelationships should be analyzed.

Evaluation of a Fatigue Detector Using Eye Closure-Associated Indicators Acquired from Truck Drivers in a Simulator Study.

This paper presents a camera-based prototype sensor for detecting fatigue and drowsiness in drivers, which are common causes of road accidents. The evaluation of the detector operation involved eight professional truck drivers, who drove the truck simulator twice-i.e., when they were rested and drowsy. The Fatigue Symptoms Scales (FSS) questionnaire was used to assess subjectively perceived levels of fatigue, whereas the percentage of eye closure time (PERCLOS), eye closure duration (ECD), and frequency of eye closure (FEC) were selected as eye closure-associated fatigue indicators, determined from the images of drivers' faces captured by the sensor. Three alternative models for subjective fatigue were used to analyse the relationship between the raw score of the FSS questionnaire, and the eye closure-associated indicators were estimated. The results revealed that, in relation to the subjective assessment of fatigue, PERCLOS is a significant predictor of the changes observed in individual subjects during the performance of tasks, while ECD reflects the individual differences in subjective fatigue occurred both between drivers and in individual drivers between the 'rested' and 'drowsy' experimental conditions well. No relationship between the FEC index and the FSS state scale was found.

IL-6 Polymorphisms Are Not Related to Obesity Parameters in Physically Active Young Men.

Interleukin 6 (IL-6) is a cytokine with both pro- and anti-inflammatory actions, but is also considered as a "metabolic hormone" involved in immune responses, affecting glucose, protein and lipid metabolism. It has been proposed to be related to obesity, but various results have been presented. Thus, in this study, the very homogenous population of young, male military professionals, living in the same conditions involving high physical activity, has been selected to avoid the influence of environmental factors. The subjects were divided into groups depending on the obesity parameters BMI (body mass index) and fat percentage (fat%), and the following IL-6 SNPs (Single Nucleotide Polymorphisms) were analyzed: rs1800795, rs1800796 and rs13306435. No relation was found between obesity parameters and IL-6 polymorphisms rs1800795, rs1800796 and rs13306435. It may be postulated that even if a genetic predisposition involves IL-6 genes, this effect in individuals with obesity of a low grade is minor, or can be avoided or at least markedly reduced by changes in lifestyle.

Deep learning-based method for the continuous detection of heart rate in signals from a multi-fiber Bragg grating sensor compatible with magnetic resonance imaging.

A method for the continuous detection of heart rate (HR) in signals acquired from patients using a sensor mat comprising a nine-element array of fiber Bragg gratings during routine magnetic resonance imaging (MRI) procedures is proposed. The method is based on a deep learning neural network model, which learned from signals acquired from 153 MRI patients. In addition, signals from 343 MRI patients were used for result verification. The proposed method provides automatic continuous extraction of HR with the root mean square error of 2.67 bpm, and the limits of agreement were -4.98-5.45 bpm relative to the reference HR.

Association between peroxisome proliferator-activated receptor-alpha, -delta and -gamma gene (PPARA, PPARD, PPARG) polymorphisms and overweight parameters in physically active men.

Peroxisome proliferator-activated receptors (PPARs) have unique functions in energy metabolism regulation but are also involved in regulation of the inflammatory process and obesity. The aim of this study was to analyse potential associations between polymorphisms of PPARA (rs1800206), PPARD (rs1053049; rs2267668) and PPARG (rs1801282) and overweight parameters. One hundred and sixty-six males, unrelated Caucasian military professionals, were recruited in the genetic case-control study conducted in the period 2016-2019. All the participants were aged 21-41 and had similar levels of physical activity. Body mass, height and body composition were measured. The participants were divided into two groups depending on their BMI (body mass index) and FMI (fat mass index). The control group consisted of people with BMI between 20.0 and 25.0 or FMI values ≤ 6, while the overweight group consisted of people with BMI of ≥ 25.0 or FMI values > 6. Genomic DNA was isolated from extracted buccal cells. All samples were genotyped using real-time polymerase chain reaction (real-time PCR). It was found that two polymorphisms rs2267668 and rs1053049 of the PPARD gene were significantly associated with BMI: SNP rs2267668 for the dominant (OR = 2.04, 95%CI 1.01-4.11, p-value = 0.04) model (A/G-G/G vs A/A). The likelihood of being overweight was over 2 times smaller for allele A. A relationship between the polymorphism of PPARG (rs1801282) and BMI was found for the overdominant (OR = 2.03, 95%CI 1.03-4.00, p-value = 0.04) model (C/G vs C/C-G/G). Significant associations were found in different models for PPARD, PPARG and PPARA genes with BMI. In SNP rs2267668 for the codominant genetic model (G/G vs A/A) (p-value = 0.04) and in SNP rs1053049 for the codominant (C/C vs T/T) (p-value = 0.01) and the recessive genetic model (C/C vs T/T-C/T) (p-value = 0.004) all polymorphisms were associated with BMI. In conclusion, it was found that three of the four polymorphisms (rs1053049, rs2267668, rs1801282) selected are associated with the risk of being overweight. Having said that, one has to bear in mind that DNA variants do not fully explain the reasons for being overweight. Therefore more research is needed to make a thorough assessment using the latest genomic methods in sequencing and genotyping, combined with epigenomics, proteomics, transcriptomics, and metabolomics.

Detection of respiratory rate using a classifier of waves in the signal from a FBG-based vital signs sensor.

BACKGROUND AND OBJECTIVE: Monitoring of changes in respiratory rate provides information on a patient's psychophysical state. This paper presents a respiratory rate detection method based on analysis of signals from a fiber Bragg grating (FBG)-based sensor. METHODS: The detection method is based on a system of software blocks that identify notches in the signal waveforms, determine their parameters, and then transmit them to the classifier, which decides which of them are the characteristic waves of the respiratory cycle. The classifier of respiratory waves was developed by means of machine learning methods and using the training data obtained from 10 volunteers (7 males, 3 females, age: 41.1 ±â€¯8.28 years, weight: 73.6 ±â€¯15.25 kg, height 173.5 ±â€¯6.43 cm), who were lying in the tube of a 3-Tesla magnetic resonance imaging (MRI) scanner. RESULTS: In the verification study, aimed at assessing the performance of the method for detecting respiratory rate, 15 subjects (14 males, 1 female, age: 20.2 ±â€¯3.00 years, weight: 75.47 ± 10.58 kg, height 179.13 ± 6.27 cm) were involved. Clinically satisfactory results of respiratory rate detection were obtained: root mean square error of 1.48 rpm and the limits of agreement at -2.73 rpm and 3.04 rpm. The results indicate a high efficiency of the classifier, i.e., sensitivity: 96.50 ± 3.44%, precision: 95.42 ± 2.84%, and accuracy: 92.99 ± 3.37%. CONCLUSION: The all-dielectric sensor acquires the respiration curve and the proposed scheme of computation enables for extracting respiratory rate automatically and continuously. This scheme based on machine learning procedures will be integrated into a system to facilitate non-invasive continuous monitoring of MRI patients.

A study of the relationship between the level of anxiety declared by MRI patients in the STAI questionnaire and their respiratory rate acquired by a fibre-optic sensor system.

Magnetic resonance imaging (MRI) patients often experience anxiety-related respiratory disorders, including hyperventilation, but their respiratory indicators are not routinely monitored during scanning. Free from metal parts and immune to electromagnetic radiation, fibre-optic sensors have the potential to better control the patient's condition by providing continuous non-invasive monitoring of the respiratory rate (RR). The study was purposed to assess the relationship between anxiety in MRI patients and their RR acquired by a fibre-optic sensor system. Forty-four subjects were involved in the study. The mean RR values recorded for 2 minutes immediately after the beginning and immediately before the end of the scanning were assessed relative to the State-Trait Anxiety Inventory (STAI) X-1 scores obtained immediately before and immediately after the scanning, respectively. A growth mixture model analysis was performed to statistically differentiate two groups of subjects according to the trends in repeated measures of RR. A significant lowering of the anxiety state was observed in the group characterised by a decrease in RR, whereas essentially no change in anxiety level was observed in the group with a stable RR. The t-test showed significant differences in changes in anxiety between these groups (t(39) = -2.349, p = 0.012, Cohen's d = 2.13).

Development and evaluation of a novel system for inducing orthostatic challenge by tilt tests and lower body negative pressure.

Lower body negative pressure (LBNP) is a method derived from space medicine, which in recent years has been increasingly used by clinicians to assess the efficiency of the cardiovascular regulatory mechanisms. LBNP with combined tilt testing is considered as an effective form of training to prevent orthostatic intolerance. We have developed a prototype system comprising a tilt table and LBNP chamber, and tested it in the context of the feasibility of the device for assessing the pilots' efficiency. The table allows for controlled tilting in the range from -45 to +80° at the maximum change rate of 45°/s. The LBNP value can smoothly be adjusted down to -100 mmHg at up to 20 mmHg/s. 17 subjects took part in the pilot study. A 24-minute scenario included -100 mmHg supine LBNP, head up tilt (HUT) and -60 mmHg LBNP associated with HUT, separated by resting phases. The most noticeable changes were observed in stroke volume (SV). During supine LBNP, HUT and the combined stimulus, a decrease of the SV value by 20%, 40% and below 50%, respectively, were detected. The proposed system can map any pre-programed tilt and LBNP profiles, and the pilot study confirmed the efficiency of performing experimental procedures.

[Simulator sickness and its measurement with Simulator Sickness Questionnaire (SSQ)]. / Zjawisko choroby symulatorowej oraz jej pomiar na przykladzie kwestionariusza do badania choroby symulatorowej - SSQ.

One of the most common methods for studying the simulator sickness issue is the Simulator Sickness Questionnaire (SSQ) (Kennedy et al., 1993). Despite the undoubted popularity of the SSQ, this questionnaire has not as yet been standardized and translated, which could allow us to use it in Poland for research purposes. The aim of our article is to introduce the SSQ to Polish readers, both researchers and practitioners. In the first part of this paper, the studies using the SSQ are discussed, whereas the second part consists of the description of the SSQ test procedure and the calculation method of sample results. Med Pr 2016;67(4):545-555.

Preliminary Results of the LF/HF Ratio as an Indicator for Estimating Difficulty Level of Flight Tasks.

INTRODUCTION: The main aim of this study was to differentiate the magnitude of a pilot's heart rate variability (HRV) when performing assisted and unassisted flights, as well as simple and complex flight tasks. METHODS: Cardiac monitoring in flights was carried out using a compact, mobile ECG recorder. A frequency analysis of the heart rate (HR) signal was performed to determine the ratio of low-frequency spectral power (LF) to high-frequency spectral power (HF). RESULTS: The LF/HF ratio observed in the zone (M=1.047, SD=0.059) was significantly different than the LF/HF calculated preflight (M=0.877, SD=0.043) and postflight (M=0.793, SD=0.037). There was no main effect of the flight type (unassisted zone flight vs. zone flight with an instructor) on the LF/HF parameter. However, greater psychophysiological load of a pilot was observed in the training zone flights when compared to simple circle flights (main effect of the flight type). CONCLUSIONS: As the LF/HF ratio turned out to be significantly higher in the zone than pre- and postflight, this parameter can be useful for predicting the risk of excessive stress and arousal of pilots during flights. Based on the LF/HF ratio we can also estimate difficulty level of flight tasks, because our research has shown higher values of this parameter in the training zone flights than in simple circle flights.

A method of detecting heartbeat locations in the ballistocardiographic signal from the fiber-optic vital signs sensor.

We present a flexible, easy-to-expand digital signal processing method for detecting heart rate (HR) for cardiac vibration signals of fiber Bragg grating (FBG) sensor. The FBG-based method of measuring HR is possible to use during the magnetic resonance imaging procedure, which is its unique advantage. Our goal was to design a detection method with plurality of parameters and to subject these parameters to genetic algorithm optimization technique. In effect, we arrived at a method that is well able to deal with much distorted signals with low SNR. We proved that the method we developed allows automatic adjustment to the shape of the waves of signal carrying useful information about the moments of heartbeat. Thus, we can easily adapt our technique to the analysis of signals, which contains information on HR, from sensors employing different techniques of strain detection. The proposed method has the capabilities of analyzing signals in semi-real-time (online) with beat-to-beat resolution, significantly low delay, and negligible computational power requirements. We verified our method on recordings in a group of seven subjects. Verification included over 6000 heartbeats (82 min 47 s of recordings). The root-mean-square error of our method does not exceed 6.0 bpm.

Fiber-optic sensors for monitoring patient physiological parameters: a review of applicable technologies and relevance to use during magnetic resonance imaging procedures.

The issues involved with recording vital functions in the magnetic resonance imaging (MRI) environment using fiber-optic sensors are considered in this paper. Basic physiological parameters, such as respiration and heart rate, are fundamental for predicting the risk of anxiety, panic, and claustrophobic episodes in patients undergoing MRI examinations. Electronic transducers are generally hazardous to the patient and are prone to erroneous operation in heavily electromagnetically penetrated MRI environments; however, nonmetallic fiber-optic sensors are inherently immune to electromagnetic effects and will be crucial for acquiring the above-mentioned physiological parameters. Forty-seven MRI-tested or potentially MRI-compatible sensors have appeared in the literature over the last 20 years. The author classifies these sensors into several categories and subcategories, depending on the sensing element placement, method of application, and measure and type. The author includes five in-house-designed fiber Bragg grating based sensors and shares experience in acquiring physiological measurements during MRI scans. This paper aims to systematize the knowledge of fiber-optic techniques for recording life functions and to indicate the current directions of development in this area.

Mood and simulator sickness after truck simulator exposure.

OBJECTIVES: Studies involving simulators are increasingly popular. We examined to what extent exposure to a variety of test conditions on the simulator affects the level of mood and severity of simulator sickness. In addition, we were interested in finding out to what degree the changes in mood are associated with the severity of the symptoms of simulator sickness. MATERIAL AND METHODS: Twelve men (aged M: 29.8, SD: 4.26) participated in the study, performing two 30-minute tasks in a driving simulator truck (fixed-base and mobile platform). For measuring mood, the UMACL questionnaire was used, and to assess the severity of the symptoms of simulator sickness, the SSQ questionnaire was used. Mood and the severity of simulator sickness symptoms were measured 3 times during the study (pretest, 2 min and 0.5 h after the test). RESULTS: Symptoms of nausea and disorientation occurred after the tests on both simulators. In the case of the mobile platform, exacerbation of the symptoms associated with oculomotor disturbances was observed. These symptoms were particularly severe 2 min after completion of the test on the simulator, and they persisted for at least 0.5 h after the end of the test. The correlations between simulator sickness and mood explained from 35% to 65% of the variance of these variables. In particular, a strong association was observed between the oculomotor disturbances and a decrease in energetic arousal. This refers both to the effect level and the duration of these symptoms. CONCLUSIONS: Simulator sickness is a major problem in the use of simulators in both the research and the training of operators. In the conditions involving the mobile platform, not only was a higher severity of the symptoms of simulator sickness observed, but also a decrease in energetic arousal. Therefore, the implementation of the mobile platform can provide an additional source of conflict at the level of incoming stimuli and changes in mood may increase this effect. Thus, it seems important to consider the tasks performed on the simulator in the context of utility and the purpose for which we use them.

The effects of simulated fog and motion on simulator sickness in a driving simulator and the duration of after-effects.

In the study, we checked: 1) how the simulator test conditions affect the severity of simulator sickness symptoms; 2) how the severity of simulator sickness symptoms changes over time; and 3) whether the conditions of the simulator test affect the severity of these symptoms in different ways, depending on the time that has elapsed since the performance of the task in the simulator. We studied 12 men aged 24-33 years (M = 28.8, SD = 3.26) using a truck simulator. The SSQ questionnaire was used to assess the severity of the symptoms of simulator sickness. Each of the subjects performed three 30-minute tasks running along the same route in a driving simulator. Each of these tasks was carried out in a different simulator configuration: A) fixed base platform with poor visibility; B) fixed base platform with good visibility; and C) motion base platform with good visibility. The measurement of the severity of the simulator sickness symptoms took place in five consecutive intervals. The results of the analysis showed that the simulator test conditions affect in different ways the severity of the simulator sickness symptoms, depending on the time which has elapsed since performing the task on the simulator. The simulator sickness symptoms persisted at the highest level for the test conditions involving the motion base platform. Also, when performing the tasks on the motion base platform, the severity of the simulator sickness symptoms varied depending on the time that had elapsed since performing the task. Specifically, the addition of motion to the simulation increased the oculomotor and disorientation symptoms reported as well as the duration of the after-effects.

Fiber Bragg grating-based sensor for monitoring respiration and heart activity during magnetic resonance imaging examinations.

We present a fiber-optic sensor for monitoring respiration and heart activity designed to operate in the magnetic resonance imaging (MRI) environment. The sensor employs a Plexiglas springboard, which converts movements of the patient's body lying on the board (i.e., lung- and heart-induced vibrations) to strain, where a fiber Bragg grating attached to the board is used to measure this strain. Experimental studies are carried out during thoracic spine MRI examinations. The presence of the metal-free sensor construction in the MRI environment does not pose a threat to the patient and has no influence over the quality of imaging, and the signal is identical to that obtained without any electromagnetic interference. The results show that the sensor is able to accurately reflect the ballistocardiographic signal, enabling determinations of the respiration rate (RR) and heart rate (HR). The data delivered by the sensor are normally distributed on the Bland-Altman plot for the characteristic point determination and exhibit clear dependence on the RR and HR values for the RR and HR determinations, respectively. Measurement accuracies are better than 7% of the average values, and thus, with further development, the sensor will be implemented in routine MRI examinations.

[Simulator sickness as a valid issue of simulator-based research]. / Choroba symulatorowa jako realny problem badan na symulatorach.

Simulators are increasingly being used in both research and training as well as in medicine, e.g., therapy of patients with diagnosed post traumatic stress disorders (PTSD). The use of simulators with strict control of environmental conditions allows for workload assessment or procedures improvement. Despite all the advantages of the utilization of simulators, the simulator sickness issue remains still topical. Simulator sickness may interfere with the measurement accuracy or effectiveness of training or therapy, but it can also be a source of stress for those carrying out the assignments on simulators. This article discusses problems associated with simulator sickness, paying particular attention to the scope of this phenomenon, its explaining theories and measurement methods.