Relationship between acute stress and sleep disorder in grass-root military personnel:Mediating effect of social support

Background: To explore the relationship between acute stress, social support and sleep disorder in grass-root military personnel, and construct the relational model through structural equation modeling. Methods: A total of 2,411 grass-root military personnel were randomly selected by cluster sampling, and administered the Chinese Military Personnel Sleep Disorder Scale, Military Acute Stress Scale and Social Support Rating Scale.Results: The total score of acute stress scale was positively correlated with the total score and factor scores of sleep disorder scale(r=0.209~0.465, P【0.01); The total score of social support scale was positively correlated with the total score of acute stress scale and the total score and factor scores of sleep disorder scale(r=0.356~0.537, P【0.01). The analysis of mediating effects showed that lack of social support partially mediated between acute stress and the factors of sleep disorder. The analysis of structural equation model showed that acute stress not only had a direct effect on sleep disorder(the path coefficient was 0.29, P=0.000), but also on lack of social support(the path coefficient was 0.39, P=0.000); lack of social support had a direct effect on sleep disorder(the path coefficient was 0.48, P=0.000).Conclusions: Acute stress and lack of social support are two significant factors of sleep disorder in grass-root military personnel. Well-established social support could alleviate sleep disorder induced by acute stress. Lack of social support was a partial mediator between acute stress and sleep disorder.

Relative longevity among retired military personnel: an historical-cohort study

Background: Occupation is a significant factor in life, health and well-being. Long-term military service is a unique career path that may influence life expectancy, even after excluding obvious risks such as battlefield mortality. However, it remains unclear what the effects of a military career are on the life trajectory of personnel who retire from service. We aimed to compare life expectancy among retired military personnel(RMP) to their sex- and birth cohortspecific reference populations.Methods: For this historical-cohort study we collected data on sex, year of birth, year of death, time in service, and rank at end of service for 4,862 Israeli RMPs. Data on reference populations were provided by the Israel Central Bureau of Statistics, by birth decade from 1900 to 1989. We calculated the difference between each individual RMP's age at death and the "expected" age at death, based on sex- and birth cohort-specific means in the reference populations. Results: Overall, 67.9% of RMPs lived longer than average relative to their sex specific birth cohort. This difference in life expectancy was more pronounced among women than among men. There was a significant trend of increasing difference between RMP males and reference males over time(P<0.002), whereas no significant trend was identified among females. Length of service and rank were not associated with relative longevity for RMPs.Conclusions: The mechanism of the protective effect of military service on life expectancy remains unknown, but our findings indicate that it affects men and women differently, with women being more likely to benefit from the protective effect of military service. The healthy worker effect is known to vary from one occupation to another. To the best of our knowledge, this is the first attempt to quantify the magnitude of the healthy worker effect among career military servicemen and women.

Hydration status,body composition,and anxiety status in aeronautical military personnel from Spain:a crosss-ectional study

Background: An adequate hydration status is critical to ensure efficiency during mental and physical activities.Our goal was to assess the hydration status of a Spanish group of aeronautical military men and to determine the association of hydration status with body composition and anxiety.Methods: A total of 188 men were evaluated through a validated hydration questionnaire, anthropometric and biochemical parameters, and an anxiety questionnaire. Based on these methods, the criteria of hydration were established.Results: Of the total sample, 81% met the hydration criteria(urine color = well hydrated, water balance ≥0 ml, and total water intake/weight ≥35 ml/kg), and 19% did not meet the hydration criteria(urine color = not sufficiently hydrated or dehydrated, water balance <0 ml, and total water intake/weight <35 ml/kg). Subjects not meeting the hydration criteria had lower urine pH, negative water balance, and lower water intake. The latter also had higher anxiety status(score=4 vs. 3, P=0.026), weight [(84.7±10.5) kg vs.(80.5±10.2) kg], body mass index [(26.3±3.1) kg/m;vs.(25.2±2.8) kg/m;], body fat [(22.3±5.6)% vs.(18.3±6.5)%], urine specific gravity, and urine color. Using a logistic binary regression model, hydration status was related significantly with the percentage of body fat(P=0.004), but no relation was found with age, comorbidities, or medications. Furthermore, total water intake/weight was positively correlated with percentage of body water(r=0.357, P=0.000) and negatively with body fat(kg)(r=–0.427, P=0.000), percentage of body fat(r=–0.405, P=0.000), and waist/hip ratio(r=–0.223, P=0.002). Based on a linear regression model, total water intake/weight was related significantly with percentage of body fat(P=0.001) and percentage of body water content(P=0.035). No relation was found, however, with waist/hip ratio, age, comorbidities, or medications.Conclusions: These findings all suggest a relationship between hydration status and body composition but also set the bases for future studies that relate hydration status and anxiety status. These results can be used to improve the hydration status and body composition of military personnel.

Laser in situ keratomiileusis surgery is not safe for military personnel

Objective： To investigate the relationship between eye injury and laser in-situ keratomileusis （LASIK） surgery in military personnel. Methods： This retrospective study collected the data from 27 evacuation hospitals of Chinese army. All medical records of eye injuries in military personnel admitted to the 27 hospitals between January 2006 and December 2010 were reviewed. Patients＇ detailed information was analyzed, including the injury time, place, type, cause, as well as examination, treatment and outcome. Results： There were 72 eye-injured patients who had been treated by LASIK before. The incidence was risingyear by year. Among them, 69 patients were diagnosed with mechanical ocular injury and 3 with non-mechanical ocular injury; 29 patients had traumatic flap-related complications and 21 patients need surgery. There was statistical difference when compared with those having no refractive sur- gery history. Visual acuity recovered well at discharge. Conclusion： There is a high risk of potential traumatic flap problems after LASIK and it is not recommended in army service.

Epidemiology of eye injuries sustained by military personnel in China

Objective： To investigate the epidemiological characteristics of eye injuries sustained by military personnel in Chinese army. Methods： Eleven military evacuation hospitals located in different regions were selected for this study. We reviewed all the medical records of eye injuries sustained by military personnel between January 2005 and December 2009. Patients＇ information was collected. All data were put into database and analyzed statistically. Results： Totally there were 415 inpatients with eye injuries （442 eyes） and their mean age was 24.40 years. Eye injury accounts for 13.51% of all eye diseases in this study. From 2006 to 2009, the number of eye injury increased gradually. Among them, 175 （42.17%） were injured in leisure time, and 145 （34.94%） in working time. Twenty-two （5.30%） patients had an eye surgery or history of eye disease before injury. In all, 246 patients （59.28%） were sent to evacuation hospital within 24 hours and 64 （56.64%） underwent surgeries in 24 hours after injury. There were 389 patients （93.73%） hospitalized for 1 time. Visual acuities of 187 eyes （42.31%） were grade 1 （≥ 20/40） after injury. When discharge, 349 eyes （78.96%） obtained a visual acuity of grade 1. Conclusion： Eye injury has a very frequent incidence in Chinese army and much more attention should be paid to prevent it.

Impact of adolescent complex regional pain syndrome on the psychopathology of young men ahead of military service: A retrospective cohort analysis of Korean conscription data

Background: The relationship between physical and psychopathological features in complex regional pain syndrome(CRPS) has been a subject of constant interest, but no data are available in adolescents. Therefore, we aimed to identify the factors associated with psychopathology in adolescents with CRPS ahead of military service.Methods: We retrospectively reviewed all conscription examinees who had completed a Military Personality Inventory(MPI) during a period between February 2013 and December 2016. A total of 63 persons with a history of CRPS(19-years of age for all) were enrolled. Basic demographic and pain-related data were analyzed to examine their association with MPI results. The mean FGR score as well as the 8 subdomain scores were compared between those with pain duration at <15 months(n=30) vs. ≥15 months(n=33). Binary MPI results(normal-abnormal) were also compared between the two groups.Results: In multivariate analysis, abnormal MPI was associated with pain duration, with an odds ratio(OR) at 1.05 for every 1-month increase [95% confidence interval(CI) 1.02–1.08;P=0.002]. Subjects with pain duration at ≥15 months have lower faking good response score(P<0.001 vs. those with pain duration at <15 months), and higher abnormal MPI result rate, faking bad response, inconsistency, anxiety, depression, somatization, paranoid, personality disorder cluster A, and personality disorder cluster B scores(P<0.05). Pain duration was significantly associated with the MPI variables.Conclusions: Pain duration is associated with psychopathology in adolescents with CRPS. Psychopathologic features increased as the disease duration increased. A comprehensive understanding of time-dependent psychopathological factors could support the planning of multimodal approaches for managing adolescent CRPS.

Comparison of dietary intakes of Canadian Armed Forces personnel consuming field rations in acute hot, cold, and temperate conditions with standardized infantry

Background:Dietary Reference Intakes are used to guide the energy intake of the Canadian Armed Forces(CAF)field rations provided to military personnel deployed for training or operations.However,the high energy expenditures likely to occur under harsh environmental/metabolically challenging deployment conditions may not be adequately considered.This study examined the Ad libitum energy and nutrient intakes of CAF personnel(n=18)consuming field rations in a resting thermoneutral environment and during a day of standardized strenuous infantry activities at varying environmental temperatures.Methods:Dietary intake was assessed using a measured food intake/food waste method during the experimental treatment and for 6 h after treatment.Four treatments were administered in a randomized counterbalanced design:exercise(as standardized infantry activities)in the heat(30℃),exercise in the cold(–10℃),exercise in temperate thermoneutral(21℃)air temperatures and a resting(sedentary)trial(21℃).Results:The average Ad libitum consumption of field rations was 70%of the provided total energy(2776±99 kcal/8 h)during all treatments.Even with an acute challenge of increased energy expenditure and temperature stress in the simulated field conditions,participants’energy intakes(1985±747 kcal/8 h)under hot,cold and temperate treatments did not differ from energy intake during the sedentary condition(1920±640 kcal/8 h).Participants’energy intakes(1009±527 kcal/6 h)did not increase during the 6 h posttreatment period when the stresses of the strenuous physical activities and the harsh environmental temperatures had subsided.Conclusions:These results should be considered when planning the provision of field rations for CAF personnel expected to be engaged in strenuous physical activities with prolonged exposure to temperature extremes.

Impact of noise on hearing in the military

Hearing plays a vital role in the performance of a soldier and is important for speech processing. Noise-induced hearing loss is a significant impairment in the military and can affect combat performance. Military personnel are constantly exposed to high levels of noise and it is not surprising that noise induced hearing loss and tinnitus remain the second most prevalent service-connected disabilities. Unfortunately, unlike civilian personnel, military personnel have little option but to remain in noisy environments in order to complete specific tasks and missions. Use of hearing protection devices and follow-up audiological tests have become the mainstay of prevention of noise-induced hearing loss. This review focuses on sources of noise within the military, pathophysiology and management of patients with noise induced hearing loss.

Acute Respiratory Disease at a Chinese Military Recruitment Training Center: Three-Year Consecutive Investigation

Background Military recruits are at a higher risk of acute respiratory disease(ARD) and the causative agents might change over time, which needs to be investigated. Methods The nasopharyngeal swabs and blood samples were consecutively collected from conscripts for three years in a military training center. The real-time fluorescent quantitative PCR assays were conducted for 15 species of common respiratory pathogens; the serum anti-Legionella pneumophila antibodies were detected by indirect immunofluorescence(IIF) assay, and serum anti-Microplasma pneumoniae antibodies, serum anti-influenza B virus and anti-influenza A virus-Ig M and Ig G were detected by ELISA. Results The prevalences of ARD were 59.3%(108/182) in 2008, 23.3%(50/215) in 2009,and 19.6%(40/204) in 2010. Among the patients with ARD from 2008 to 2010, the influenza B virus infection accounted for 45.4%, 30.0% and 55.0%, and seasonal influenza A virus infection for 8.3%, 8.0% and 5.0%, respectively; the positive rates of serum anti-Legionella pneumophila and anti-Microplasma pneumoniae antibodies in recruits was lower than 10% each year respectively in the three years without diagnostic significance. Conclusion The early appropriate diagnosis and treatment of ARD in military personnel will ensure the power strength of armed forces.

Prevalence of musculoskeletal injuries and a proposal for neuromuscular training to prevent lower limb injuries in Brazilian Army soldiers:an observational study

Background: The activities carried out by soldiers in the army involve great physical demands and require intense trainings to perform combat-specific tasks. Musculoskeletal injury is a potential threat to the health and physical integrity of the soldier. This study aimed to evaluate the prevalence of lower limb musculoskeletal injuries among soldiers and to propose a training protocol to prevent the most frequent injuries.Methods: This observational(cross-sectional) study recruited a sample of 103 soldiers who required medical attention,from a total 202 new battalion soldiers. The medical records(paper and online) had a form of running text. All data collected were recorded by the registered physicians of the battalion medical post. The records were analyzed by the following variables: medical diagnosis, injury site, mechanism, type of treatment, time loss, existence of previous injury,and recurring injury.Results: A total of 112 musculoskeletal injuries were diagnosed in 71 soldiers, and other types of diseases/injuries were diagnosed in the other soldiers. Joint pain accounted for 55.4% of the diagnoses. The knee was the most affected site, while trauma and overload were the most common mechanisms of injury. Drug treatment was used most frequently, accounting for 58% of the cases. The majority of the sample obtained a temporary leave of absence for1 to 6 days or not at all. Previous injuries and recurrence were not presented as risk factors for injury. With the data received, a protocol for the prevention of injuries to the lower limbs was proposed.Conclusions: This study indicated that the most frequent site of injury is the knee, and joint pain is the most common diagnosis. These results may support the necessity to develop a neuromuscular training protocol to prevent lower limb injuries, which we suggest to be applied in future studies.

Emerging and re-emerging infectious diseases: Challenges and opportunities for militaries

The communal nature of living and training environments, alongside suboptimal hygiene and stressors in the field, place military personnel at higher risk of contracting emerging infectious diseases. Some of these diseases spread quickly within ranks resulting in large outbreaks, and personnel deployed are also often immunologically na?ve to otherwise uncommonly-encountered pathogens. Furthermore, the chance of weaponised biological agents being used in conventional warfare or otherwise remains a very real, albeit often veiled, threat. However, such challenges also provide opportunities for the advancement of preventive and therapeutic military medicine, some of which have been later adopted in civilian settings. Some of these include improved surveillance, new vaccines and drugs, better public health interventions and inter-agency co-operations. The legacy of successes in dealing with infectious diseases is a reminder of the importance in sustaining efforts aimed at ensuring a safer environment for both military and the community at large.