Objective:To investigate the diagnosis, treatment, prognosis and aeromedical assessment of nasopharyngeal non-Hodgkin lymphoma (NHL) in civil aviation pilots.Methods:The clinical data of a civil pilot with nasopharyngeal NHL was retrospectively analyzed while related literature was reviewed. The clinical characteristics, diagnosis, treatment, prognosis and identification of nasopharyngeal NHL were traced.Results:A civil pilot was diagnosed with nasopharyngeal NHL in January 2016 before being grounded by aviation physicians. After treatment with systematic chemoradiation and chemotherapy by the Department of Oncology, West China Hospital of Sichuan University, the patient′s results of blood routine tests, blood biochemistry, EB virus DNA detection, electrical audiometry, and sound immittance returned to normal as evidenced by multiple outpatient examinations between June 2016 and April 2017. No signs of malignant tumor were found by fiber nasopharyngoscopy, nasopharyngeal MRI or positron emission tomography/computed tomography. In June 2017, he applied for specially-permitted assessment for the first time, and the aeromedical assessment conclusion was waiver to flight, but his flight was limited to 60 h or less. The pilot was able to perform flight duties ever since. EB virus DNA detection, nasopharyngeal MRI, fiber nasopharyngoscopy and other related examinations were repeated in each physical examination, and the pilot was given specially-permitted eligibility for fight missions annually for 6 consecutive years, but the monthly flying hours was limited to 60 h or less. So far, the disease neither recurred nor progressed.Conclusions:Nasopharyngeal NHL is rare in civil aviation pilots, so missed diagnosis and misdiagnosis should be avoided. Patients with nasopharyngeal NHL who have recovered after treatment may apply for specially-permitted health assessment and resume their work after comprehensive assessment by related experts.

Objective:To investigate the effects of 10° head up tilt bed rest (HUT) on human cardiac function via 3D speckle tracking echocardiography (3D-STE), and to study the difference in cardiac function under the submaximal exercise load between the horizontal position and 10° HUBR.Methods:Thirty young healthy volunteers were recruited as the subjects, who were randomly divided into an 10° HUT exercise group and horizontal exercise group with 15 subjects in each. Subjects in both groups were asked to ride the bicycle ergometer in the 10° HUBR position and supine position respectively. The load started with 50 W and was increased by 25 W every 3 min until it reached the maximum of 125 W. Before the exercise (resting state), 1 min after the load was increased each time, and 3 min after exercise (recovery period), the following indices were collected: ①basic cardiac function indices: heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), ②conventional cardiac ultrasound indices: left ventricular ejection fraction (LVEF), stroke volume (SV) and cardiac output (CO), ③left ventricular strain indices: global longitudinal strain (GLS), global circumferential strain (GCS), and global area strain (GAS) measured by 3D-SET. The changes of these indices in the 2 groups of subjects under different exercise loads were observed.Results:The differences in the major effect of the basic heart indices (HR, SBP and DBP), conventional cardiac ultrasound indices (LVEF, SV and CO) and left ventricular strain indices (GLS, GCS and GAS) in response to the exercise load were statistically significant ( F=194.90, 113.66, 17.19, P=0.017, 0.018, 0.001). With the increase of the exercise load, the basic heart indices and conventional cardiac ultrasound indices kept rising, the left ventricular strain indices reached the minimum under a moderate exercise load (75 W), HR, SBP and CO were higher than those of the resting state ( P<0.05 or 0.01). Both LVEF under exercise loads of 75, 100, 125 W and during recovery, and SV under exercise loads of 100, 125 W and during recovery were significantly higher than those of the resting state ( P<0.05 or 0.01), while GLS and GCS under exercise loads of 50, 75, 125 W ( P<0.05 or 0.01), and GAS under exercise loads of 50, 75 W ( P<0.01) were significantly lower. There were statistically significant differences not only in GCS across the groups ( F=4.60, P=0.026) but also in DBP due to the interactions between the grouping and exercise loads ( F=3.13, P=0.031). DBP was higher than that of the resting state when the exercise load was 125 W in both groups. Conclusions:During submaximal exercise, myocardial contractility shows sustained enhancement with the increase of the exercise load. The results of GLS, GCS and GAS indicate that myocardial strain reaches its lowest value under a moderate exercise load, suggesting that moderate exercise can be used to evaluate cardiac function via 3D-SET. Under a simulated lunar gravity of 10° HUT, there is less deformation in the short axis direction of the myocardium, indicating that GCS can be used as a sensitive indicator to detect changes in cardiac function under different gravities.

Objective:To investigate the characteristics and determinants of total scores of cerebral small vessel disease (CSVD) and to analyze the factors associated with enlarged perivascular space (EPVS) grading in pilots.Methods:The physical examination data of 72 pilots who were hospitalized and diagnosed with CSVD by MRI in the Air Force Medical Center (General Hospital of Air Force) between 2019 and 2022 was retrospectively analyzed. The pilots were grouped by the total CSVD score (0, 1, 2, 3, 4 points), and the distribution of CSVD imaging biomarkers was compared across groups. The severity of EPVS was classified into 3 levels: none or mild (0-10), moderate (11-20), and severe (>20). The impact of vascular risk factors on the total CSVD score and EPVS grading was analyzed.Results:The results of the total CSVD score showed that there were 19 cases (26.39%) with a score of 0, 43 cases (59.72%) with a score of 1, 10 cases (13.89%) with a score of 2, and 0 case with scores of 3 or 4. Among those who scored 1, there were 2 cases (4.65%) of lacunar infarction (LA), 1 case (2.33%) of moderate to severe white matter hyperintensity (WMH), 2 cases (4.65%) of cerebral microbleed (CMB), and 38 cases (88.37%) of moderate and severe EPVS. Among those who scored 2, there were 7 cases (70.00%) of LA combined with EPVS, 2 cases (20.00%) of CMB combined with EPVS, and 1 case (10.00%) of WMH combined with EPVS. According to the CSVD imaging classification of these pilots, there were 9 cases (12.50%) of LA, 52 cases (72.22%) of WMH, 4 cases (5.60%) of CMB and 61 cases (84.72%) of EPVS. Multiple ordered Logistic regression analysis showed that systolic blood pressure ( OR=1.068, 95% CI: 1.016-1.122) and high-density lipoprotein cholesterol ( OR=0.111, 95% CI: 0.015-0.843) made a difference in the total CSVD score. High-density lipoprotein cholesterol ( OR=0.166, 95% CI: 0.031-0.893) could affect the EPVS grading. Spearman′s correlation analysis showed that the systolic blood pressure level was positively correlated with the total CSVD score ( r=0.299, P=0.011), while the high-density lipoprotein cholesterol level was negatively correlated with the total CSVD score and EPVS grading ( r=-0.313, -0.263, P=0.041, 0.026). Conclusions:The total CSVD score of pilots is at a mild level with EPVS as the leading contributor. The systolic blood pressure and the high-density lipoprotein cholesterol level are determinants for the total CSVD score, while the high-density lipoprotein cholesterol level is a determinant for the EPVS grading of pilots. Blood pressure control and lipid regulation can go a long way towards preventing CSVD in pilots. The total CSVD score is of value for stratified evaluation and individual identification of pilots with CSVD.

Objective:To explore the distribution and determinants of abnormal blood lipid metabolism among flying personnel with lumbar disc herniation and with different flying hours and to provide data for targeted intervention strategies.Methods:The hospitalization data of 214 male flying personnel was retrospectively analyzed who were admitted to the Air Force Medical Center between September 2020 and September 2023, diagnosed with lumbar intervertebral disc protrusion, and underwent blood lipid testing within 24 h of admission. According to the hours of flying, they were divided into <1 000 h group (45 cases), 1 000-<3 000 h group (107 cases), and ≥3 000 h group (62 cases). The blood lipid biochemical indicators [total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol (non-HDL-C)], basic information and personal history of the flying personnel were collected. The detection rates of blood lipid metabolism disorders among flying personnel with different durations of flight were compared. The chi-square test for linear trend was used to find out whether there was a trend of linear changes in the detection rates of various blood lipid disorders. The multivariate Logistic regression analysis was conducted to analyze the determinants of abnormal blood lipid metabolism.Results:There were significant differences in age, levels of total cholesterol and low-density lipoprotein cholesterol, and non-HDL-C between flying personnel in different flying hours groups ( F=80.76, 4.67, 4.00, 6.35, P<0.001,=0.010, 0.020, 0.002). The levels of total cholesterol and low-density lipoprotein cholesterol, and non-HDL-C in the 1 000-<3 000 h group were higher than those in the <1 000 h group ( P=0.023, 0.029, 0.003). The total detection rate of elevated triglyceride was the highest (28.04%). There was a significant difference in the detection rate of elevated low-density lipoprotein cholesterol between the 3 groups ( χ2=6.50, P=0.039), which was lower in the 1 000-<3 000 h group than in the <1 000 h group ( P=0.010). The results of the chi-square analysis of linear association showed that with the increase of flight duration, there was a linear decrease in the detection rates of elevated total cholesterol and elevated non-HDL-C ( χ2=4.17, 4.16, P=0.041, 0.041). The univariate Logistic regression analysis showed that compared with the <1 000 h, the 1 000-<3 000 h was an influencing factor for elevated triglyceride ( OR=4.406, 95% CI: 1.604-12.103) and elevated non-HDL-C ( OR=6.217, 95% CI: 1.403-27.551) while body mass index was an influencing factor for elevated total cholesterol ( OR=1.237, 95% CI: 1.055-1.450) and elevated non-HDL-C ( OR=1.298, 95% CI: 1.087-1.548). Current smoking was an influencing factor for elevated triglyceride ( OR=3.214, 95% CI:1.700-6.078) and decreased high-density lipoprotein cholesterol ( OR=3.200, 95% CI: 1.724-5.941). The multivariate Logistic regression analysis showed that body mass index was a risk factor for elevated total cholesterol ( OR=1.245, 95% CI: 1.054-1.471) and elevated non-HDL-C ( OR=1.301, 95% CI: 1.082-1.564). Current smoking was a risk factor for elevated triglyceride ( OR=3.439, 95% CI: 1.550-7.631) and decreased high-density lipoprotein cholesterol ( OR=4.047, 95% CI: 1.901-8.729). Conclusions:Flying personnel with lumbar intervertebral disc protrusion and with different flying hours exhibit distinct features of phased blood lipid metabolism disorders. The triglyceride levels of those with 1 000-<3 000 h deserve more attention while the levels of low-density lipoprotein cholesterol should be brought under control for those with <1 000 h. It is recommended that hierarchical interventions be exercised according to flight stages, and that priority be given to controlling daily adjustable behavioral factors such as body mass index and smoking.

Objective:To review the current research on mechanisms for bone and muscle loss among astronauts in a microgravity environment and predict progress in prevention and treatment. Literature resource and selection Related literature retrieved from CNKI, Wanfang Data, PubMed and other Chinese and English databases that was published as of December 2023. Such key words as weightless, microgravity, bone, muscle and osteoporosis were used. Literature quotation Fifty seven related articles that had been published at home and abroad were included. Literature synthesis The loss of bone and muscle in a microgravity environment was receiving increasing attention in the field of aerospace medicine, but the process of bone and muscle loss was influenced by a range of factors. The microgravity environment altered the function and expression of osteoblasts, osteocytes and osteoclasts, thus impacting bone formation, mineralization and absorption. In addition, the microgravity environment led to muscle cell atrophy, apoptosis, functional decline and degradation of muscle proteins. Complex signaling pathways and molecular regulatory mechanisms existed between bone and muscle cells, and these interactions were disrupted in the microgravity environment. Conclusions:Current strategies for prevention and treatment of bone and muscle loss in a microgravity environment include mechanical stimulation, pharmacologic interventions and nutritional supplementation. More effort is needed to study the related mechanisms and targets.

Objective:To provide references for the research on visual fatigue by reviewing the advances in diagnosis and treatment of pilots at home and abroad.Literature resource and selection:Related literature on visual fatigue published at home and abroad.Literature quotation:Forty-one references were cited.Literature synthesis:The pathogenesis of visual fatigue is different between fighter/transporter/helicopter pilots and unmanned aerial vehicle pilots. The causes of visual fatigue are also different between military pilots and the general population. Diagnosis primarily relies on subjective evaluation scales, for objective and quantifiable indicators are lacking that can help assess the level of visual fatigue and its impact on flight safety. Most of the treatments that focus on symptomatic relief are ineffective for military pilots. Safe and effective treatment regimens and precautions are badly needed. In this regard, traditional Chinese medicine promises very good applications.Conclusions:Visual fatigue experienced by military pilots has a significant impact on their visual task performance. Therefore, it is of critical importance to accurately access the severity of visual fatigue in military pilots and its impact on flight safety, and find effective means to manage and prevent this disease. TCM-related research should be given priority.

Objective:To analyze the patterns of change of brain function among civil pilots in prospective memory tasks by using task-state functional magnetic resonance imaging (fMRI) and a cue-based repetitive search task.Methods:A total of 85 subjects were enrolled, including 47 civil pilots (pilot group) and 38 ordinary workers (control group). The task-state fMRI data during the execution of the prospective memory task was analyzed using a general linear model to find out about the activation patterns of brain functions in the 2 groups in the 3 phases of encoding, maintenance, and retrieval of the prospective memory task. The differences in activation patterns between the 2 groups and correlations between regions of interest and the rate of accuracy, reaction time and flying hours were analyzed.Results:The repeated measurement analysis of variance showed that there were no interactions of reaction time or of the rate of accuracy between the task and grouping ( P>0.05), and that the difference in the main effect of grouping was significant ( F=5.67, 15.46, P=0.020, <0.001). The difference in the main effect of grouping on the rate of accuracy was significant ( F=5.42, P=0.022), and the rate of accuracy in the pilot group was higher than in the control group ( P=0.048). In the phase of encoding, the activation in the bilateral cerebellum, bilateral superior frontal gyrus, bilateral fusiform gyrus, and temporal lobe regions decreased in the pilot group compared with the control group ( t=2.68-4.13, all P<0.05), while the activation in the fusiform gyrus and the right parietal superior gyrus increased, and the differences were statistically significant ( t=3.28, 3.35, 3.02, P=0.038, 0.024, 0.042). During the phase of maintenance, the pilot group showed significantly reduced activation in the bilateral cerebellum, bilateral medial superior frontal gyrus, bilateral middle occipital gyri, and the right middle temporal gyrus compared with the control group ( t=2.24-3.36, P<0.05 or 0.01). In the retrieval phase, activation in the right peri-calcarine cortex, bilateral caudate nuclei, and bilateral precentral and postcentral gyri was enhanced in the pilot group compared with the control group ( t=2.57-3.35, all P<0.05), especially in the right middle frontal gyrus ( t=3.12, P=0.007). In the encoding phase, activation was increased in the left fusiform gyrus and right parietal superior gyrus of the pilot group, which was positively correlated with flying hours in the last 3 months ( r=0.347, 0.418, P=0.020, 0.005). Conclusions:Due to long-term flights, the way in which such regions as the frontal lobe, cerebellum, and default mode network are activated in civil pilots is likely to undergo some changes during prospective memory activities, which is why they have higher processing efficiency when performing prospective memory tasks.

Objective:To analyze the results of detection and determinants of thyroid nodules among civil pilots, and to provide evidence for health management and aeromedical support.Methods:The results of health examination and flight data of 2 451 pilots at Xiamen Airlines Co., Ltd. collected between July 1, 2021 and June 30, 2022 was retrospectively analyzed. These pilots were divided into a non-nodule group and a nodule group based on thyroid ultrasound findings. Gender,age, flying hours, body mass index, prevalence of hypertension, blood routine parameters, lipid profiles, liver and kidney function, fasting plasma glucose, and long-haul flight frequency were compared between the 2 groups. Multivariate Logistic regression was performed to identify risk factors for thyroid nodules.Results:Among the 2 397 civil pilots, 2 301 were in the non-nodule group and 96 in the nodule group, with a detection rate of 4.01%. Most of these nodules were solitary and small (<1 cm in diameter, 52.08%), and classified as Chinese Thyroid Imaging Reporting and Data System 3 (likely benign, 53.13%). Detection rates of nodules were significantly higher among clivil pilots of older age or with longer flying hours ( χ2=25.17,36.86,both P<0.001). Overweight/obesity, hypertension, hypertriglyceridemia, hyperuricemia, and frequent long-haul flights were also associated with higher prevalence of thyroid nodules ( χ2=14.81, 6.17, 10.86, 11.57, 4.12, P<0.001,=0.013, 0.001, 0.001,0.042). Multivariate Logistic regression analysis pointed to the following independent risk factors: flying hours of 10 001-15 000 ( OR=4.005, 95% CI: 1.952-8.216) and over 15 000 ( OR=5.220, 95% CI: 2.415-11.285), overweight/obesity ( OR=1.646, 95% CI: 1.052-2.576) and hyperuricaemia ( OR=1.838, 95% CI: 1.204-2.804). Conclusions:The detection rate of thyroid nodules among civil pilots is relatively low. The occurrence is linked to advanced age, hypertension, hypertriglyceridemia and long-haul flight frequency, with cumulative flying hours, overweight/obesity and hyperuricemia as key risk factors. Aviation healthcare providers and medical examiners should provide targeted guidance and interventions related to modifiable risk factors to safeguard clivil pilots′ occupational health.

Objective:To evaluate the effectiveness of anti-G straining maneuver (AGSM) in pilots by surface electromyography (sEMG), and to explore the relationships between characteristics of sEMG and anti-G endurance in pilots.Methods:Thirty-eight male high-performance fighter pilots who completed the human centrifuge test at the Air Force Medical Center were selected. Among them, 25 completed the 8.0 G for 10 s anti-G endurance test and 13 completed the 9.0 G for 10 s anti-G endurance test. The sEMG tester was used to keep track of the changes of sEMG in rectus abdominis, rectus femoris, anterior tibial and gastrocnemius muscles while pilots were engaged in AGSM. The anti-G endurance was evaluated according to the changes of visual fields and consciousness. The pilots were divided into 3 groups: the good vision and consciousness group, peripheral visual field narrowing group and endurance endpoint group. The differences in the integral electromyogram (iEMG), mean power frequency (MPF) and muscle input rates between the 3 groups were investigated.Results:A total of 25 pilots completed the 8.0 G for 10 s anti-G endurance test. Among them, 8 (32.0%) were in the good vision and consciousness group, 13 (52.0%) in the peripheral visual field narrowing group and 4 (16.0%) reached the endurance endpoint. Among the 13 pilots who completed the 9.0 G for 10 s anti-G endurance test, 3 (23.1%) were in the good vision and consciousness group, 6 (46.1%) in the peripheral visual field narrowing group, and 4 (30.8%) in the endurance endpoint group. The results of sEMG showed that the iEMG values of the anterior tibialis muscle in pilots under the 9.0 G for 10 s load were significantly different across endurance groups ( H=7.54, P=0.023), and that the iEMG values of the tibialis anterior muscle in the good vision and consciousness group were higher than those in the endurance endpoint group ( P=0.036). The negative slopes of MPF for the rectus abdominis, rectus femoris, anterior tibialis, and gastrocnemius muscles were higher in the good vision and consciousness group than in the other 2 groups, but the differences were not statistically significant ( P>0.05). During the 8.0 G for 10 s anti-G endurance test, there were significant differences in lower limb muscle contribution rates between the 3 groups ( F=4.19, P=0.029). The endurance endpoint group exhibited a lower contribution rate than the good vision and consciousness group ( P=0.025). During the 9.0 G for 10 s anti-G endurance test, there were significant differences in tibialis anterior muscle contribution rates between the 3 groups ( F=4.16, P=0.049). The endurance endpoint group demonstrated a lower contribution rate than the good vision and consciousness group ( P=0.049). Conclusions:The full and balanced activation of abdominal muscles and lower limb muscles, especially the effective mobilization of calf muscles, plays a pivotal role in improving pilots′ AGSM efficiency in high G environments.

Objective:To evaluate the training efficacy of the autonomic nervous system stability assessing and enhancing capsule (hereinafter referred to as the EC), and to study the difference in physiological indicators for autonomic nervous system stability training between the EC and a non-capsule environment.Methods:A total of 1 478 male military pilots under autonomic nervous system stability training between February 2022 and February 2024 were selected before they completed training sessions in both the EC and a non-capsule environment. The pre-training time-domain and frequency-domain indices of heart rate variability (HRV) and the 0.1 Hz index were compared with the post-training ones, and across difficulty levels (low, moderate, and high). The difference that the EC made in relaxation training was analyzed.Results:①Time-domain indices of HRV were of statistical significance in the main effects of training difficulty, those of training environments, and their interactions ( F=4.40-160.80, all P<0.05 or 0.01). Simple effect analysis revealed that in the same phase of training the standard deviation of all NN intervals (SDNN) at the low level of difficulty in the EC was lower than in the non-capsule environment. However, all time-domain indices after training were higher in the EC than in the non-capsule environment. The differences were statistically significant (all P<0.05 or 0.01).②For frequency-domain HRV indices, significant differences were observed in both the main effect of training difficulty and the interactions ( F=4.40-1 524.33, all P<0.01). Very low frequency power (VLF), high frequency (HF), the ratio of low frequency to high frequency (LF/HF), normalized low frequency (LFnorm), and normalized high frequency (HFnorm) were significantly different in the main effect of training environments ( F=4.24, 12.00, 6.91, 23.39, 23.39, P=0.040, <0.001, =0.009, <0.001, <0.001). Simple effect analysis revealed that at the same level of training difficulty, the EC delivered significantly lower values of LF and LFnorm but higher values of HF and HFnorm than the non-capsule environment before training (all P<0.05). VLF across levels of training difficulty and LF/HF at the high level of difficulty level were significantly lower in the EC than in the non-capsule environment. After training, total power, VLF, LF, HF, and HFnorm were significantly higher in the EC than in the non-capsule environment, but LF/HF and LFnorm were significantly lower (all P<0.05). ③For the 0.1 Hz index, significant differences were observed in both the main effect of training difficulty and the interactions ( F=2 147.75, 6.63, both P<0.001). Subsequent simple effect analysis revealed that at the same level of training difficulty, 0.1 Hz indices of pilots in the EC were lower than in the non-capsule environment before and after training (all P<0.01). Conclusions:During the autonomic nervous system stability training, the EC can effectively and quickly regulate and alleviate pilots′ fatigue and stress. Furthermore, it provides sustained autonomic nervous system training, thereby stabilizing pilots′ autonomic nervous system.