Approximately half of cancers are attributed to modifiable risk factors or inherited genetic mutations, thus there remains the potential for as-yet unidentified environmental risk factors to explain substantially more of the global cancer burden. Current estimates of the environmental and occupational cancer burden account for a relatively small number of exposures, because of challenges in characterizing exposure patterns and human cancer risks. Hence, the environmental cancer burden may be underestimated because of combinations of not having identified all carcinogenic agents, lack of understanding of cancer risks at very low exposure levels of even known carcinogens, and lack of understanding of joint effects. The International Agency for Research on Cancer has a long history of addressing these challenges, and of advancing our understanding of occupational and environmental causes of cancer, with primary research predominantly conducted by the Environment and Lifestyle Epidemiology Branch. The International Agency for Research on Cancer's position within the World Health Organization has facilitated the conduct of cross-border collaborations on important and sensitive topics, ranging from asbestos, ionizing radiation, and pesticides to its current work on artisanal petroleum refining. Here, we highlight some important Environment and Lifestyle Epidemiology contributions to several areas of occupational and environmental cancer, describe recent progress in other important and emerging exposures, and finally, provide suggestions for future research. In our constantly changing world, with new products, technologies, and demands transforming our environment and workplaces, there is a continued need for high-quality human cancer investigations of potential occupational and environmental carcinogens, especially those characterizing environmental levels of exposure encountered by the general population in their daily life and in underresearched regions of the world.
Historically musculoskeletal injury has substantially affected United States (US) service members. Lumbosacral spine injuries are among the most common sites of injury for service members across all US military branches and usually presents with pain in the lower back and extremities. The aim of this study is to identify and describe the 50 most-cited articles relevant to military medicine on the subject of the spine. In April 2020 Web of Science was used to search the key words: spinal cord injury, spine, thoracic spine, lumbar spine, cervical spine, sacrum, sacral, cervical fusion, lumbar fusion, sacral fracture, combat, back pain, neck pain, and military. Articles published from 1900 to 2020 were evaluated for relevance to military spine orthopaedics and ranked based on citation number. The 50 most-cited articles were characterized based on country of origin, journal of publication, affiliated institution, topic, military branch, and conflict. 1900 articles met search criteria. The 50 most-cited articles were cited 24 to 119 times and published between 1993 and 2017. 30 articles (60%) originated in the United States. Aviation, Space, and Environmental Medicine accounted for the most frequent (n = 10) destination journal followed by Spine (n = 8). 37 institutions contributed to the top 50 most-cited articles. The most common article type was clinically focused retrospective analysis 36% (n = 18), clinically focused cohort study 10% (n = 5), and clinically focused cohort questionnaire, cross-sectional analysis, and randomized study 8% each (n = 4). 90% of articles were non-surgical (n = 45). The US Army had the greatest number of associated articles. Operation Iraqi Freedom and Operation Enduring Freedom were the most-cited conflicts. The 50 most-cited articles relevant to military spine orthopaedics are predominantly clinically focused, arising from the US, and published in Aviation, Space, and Environmental Medicine, Spine, and The Spine Journal.
Galactic cosmic radiation (GCR) is a naturally occurring environmental radiation that originates from outer space. GCR is modulated by solar activity, and its intensity increases with increasing geomagnetic latitude and altitude, reaching a peak of up to approximately 20 km in the atmosphere. Therefore, commercial flight passengers (flyers) are exposed to elevated levels of cosmic radiation while flying onboard commercial aircraft. Although the recent COVID-19 pandemic, which began in early 2020, is believed to have significantly affected public exposure to cosmic radiation, this impact is yet to be quantified. Based on the official records of Japanese flyers, their annual per-capita doses (APCDs) of cosmic radiation exposure on international and domestic flights were calculated using the established code JISCARD EX over a 7-year period from 2014 to 2020 (including the first year of the pandemic). For estimating the APCDs on international flights, the world was divided into eight regions. The aviation route dose to a representative city in each region was determined at three cruising altitudes: 34,000 ft. (10.4 km), 37,000 ft. (11.3 km), and 40,000 ft. (12.2 km). At a typical cruising altitude of 37,000 ft., the flyer-average APCD from international flights was estimated to be approximately 60 μSv y-1, while the APCD from domestic flights was approximately 2 μSv y-1 over the target period, including the pandemic year (2020). These results indicate that the distribution of Japanese travel destinations did not change significantly during the pandemic period. In contrast, the population-average APCD significantly decreased from approximately 10 μSv y-1 in the pre-pandemic period (2014-2019) to 2 μSv y-1 in 2020, representing a reduction of more than 80%, which corresponds to a decline in the number of travelers. The results of this study indicate that the population-average APCD of Japanese flyers decreased significantly during the COVID-19 pandemic, while the flyer-average APCD remained largely unchanged. Further studies will be performed to determine APCDs for the subsequent period and to assess the overall effect of the pandemic on public health.
Hyperbaric oxygen therapy (HBOT) involves the therapeutic administration of 100% oxygen in a pressure chamber at pressures above one atmosphere absolute. This therapy has been used as an adjunct to surgery and antibiotics in the treatment of patients with necrotizing fasciitis with the aim of reducing morbidity and mortality. To review the evidence concerning the use of HBOT as an adjunctive treatment for patients with necrotizing fasciitis (NF). Specifically, we wish to address the following questions.1. Does administration of HBOT reduce mortality or morbidity associated with NF?2. What adverse effects are associated with use of HBOT in the treatment of individuals with NF? We searched the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE Ovid (1966 to September 2014); the Cumulative Index to Nursing and Allied Health Literature (CINAHL) Ovid (1982 to September 2014); EMBASE Ovid (1980 to September 2014); and the Database of Randomised Controlled Trials in Hyperbaric Medicine (DORCTHIM, M Bennett) (from inception to September 2014). In addition, we performed a systematic search of specific hyperbaric literature sources. This included handsearching of relevant hyperbaric textbooks; hyperbaric journals (Hyperbaric Medicine Review, South Pacific Underwater Medicine Society Journal, European Journal of Underwater and Hyperbaric Medicine, Aviation Space and Environmental Medicine Journal); and conference proceedings of the major hyperbaric societies (Undersea and Hyperbaric Medical Society, South Pacific Underwater Medicine Society, European Underwater and Baromedical Society, International Congress of Hyperbaric Medicine). We included all randomized and pseudo-randomized trials (trials in which an attempt at randomization has been made but the method was inappropriate, for example, alternate allocation) that compared the effects of HBOT with the effects of no HBOT (no treatment or sham) in the treatment of children and adults with necrotizing fasciitis. We planned independent data collection by two review authors using standardized forms. We found no trials that met the inclusion criteria. This systematic review failed to locate relevant clinical evidence to support or refute the effectiveness of HBOT in the management of necrotizing fasciitis. Good quality clinical trials are needed to define the role, if any, of HBOT in the treatment of individuals with necrotizing fasciitis.
This study examined the uptake and effectiveness of fatigue mitigation guidance material including sleep recommendations for a trip with a westward ultra-long-range flight and return long-range flight. There were 52 flight crew (4-pilot crews, mean age 55 yr) who completed a sleep/duty diary and wore an actigraph prior to, during, and after the trip. Primary crew flew the takeoff and landing, while relief crew flew the aircraft during the Primary crew's breaks. At key times in flight, crewmembers rated their fatigue (Samn-Perelli fatigue scale) and sleepiness (Karolinska Sleepiness Scale) and completed a 5-min Psychomotor Vigilance Task. Napping was common prior to the outbound flight (54%) and did not affect the quantity or quality of in-flight sleep (mean 4.3 h). Primary crew obtained a similar amount on the inbound flight (mean 4.0 h), but Secondary crew had less sleep (mean 2.9 h). Subjective fatigue and sleepiness increased and performance slowed across flights. Performance was faster on the outbound than inbound flight. On both flights, Primary crew were less fatigued and sleepy than Secondary crew, particularly at top of descent and after landing. Crewmembers slept more frequently and had more sleep in the first 24 h of the layover than the last, and had shifted their main sleep to the local night by the second night. The suggested sleep mitigations were employed by the majority of crewmembers. Fatigue levels were no worse on the outbound ultra-long-range flight than on the return long-range flight.
Work is beneficial for health, but many individuals develop cardiovascular disease (CVD) during their working lives. Occupational cardiology is an emerging field that combines traditional cardiology sub-specialisms with prevention and risk management unique to specific employment characteristics and conditions. In some occupational settings incapacitation through CVD has the potential to be catastrophic due to the nature of work and/or the working environment. These are often termed 'hazardous' or 'high-hazard' occupations. Consequently, many organizations that employ individuals in high-hazard roles undertake pre-employment medicals and periodic medical examinations to screen for CVD. The identification of CVD that exceeds predefined employer (or regulatory body) risk thresholds can result in occupational restriction, or disqualification, which may be temporary or permanent. This article will review the evidence related to occupational cardiology for several high-hazard occupations related to aviation and space, diving, high altitude, emergency workers, commercial transportation, and the military. The article will focus on environmental risk, screening, surveillance, and risk management for the prevention of events precipitated by CVD. Occupational cardiology is a challenging field that requires a broad understanding of general cardiology, environmental, and occupational medicine principles. There is a current lack of consensus and contemporary evidence which requires further research. Provision of evidence-based, but individualized, risk stratification and treatment plans is required from specialists that understand the complex interaction between work and the cardiovascular system. There is a current lack of consensus and contemporary evidence in occupational cardiology and further research is required.
The prevalence, progression rates, and outcomes affecting aviator valvular heart disease have not been extensively studied. The U.S. Air Force (USAF) School of Aerospace Medicine's Clinical Sciences Database was used to determine prevalence and progression rates for regurgitant valvular disease. A subset of the initial population was further evaluated for risk factors that increased the likelihood of progression. Descriptive statistical analysis, analysis of variance, and t-test calculations were completed. There were 8475 unique aviators with some degree of valvular regurgitation for an overall prevalence of 3.0%. The mitral and aortic valves were most likely to have mild and moderate or greater regurgitation, respectively. Progression rates from mild to moderate were 8% in the aortic valve, 2% in the mitral valve, and less than 1% in the pulmonic and tricuspid valves. Progression rates from moderate to severe were over 20% for both the mitral and aortic valves. The only risk factors correlating to progression of valvular disease were lower levels of high-density lipoproteins in the mitral and aortic valves and triglycerides in the mitral valve. In USAF aviators, progression rates for mild or greater aortic valve regurgitation and moderate or greater mitral valve regurgitation are significant and should be followed closely. Classic risk factors of age, tobacco use, elevated blood pressure, and hyperlipidemia have no association with increased risk of valvular progression or rate of progression. Study outcomes validate the current USAF policy for valvular heart disease in aviators.
This study was aimed at investigating the caries status of Chinese civilian pilots and the relationship between caries and oral health behaviors, including sugar intake, smoking, alcohol consumption, tooth brushing, and dental check-up attendance. This cross-sectional investigation enrolled pilots from Shenzhen Airline. A questionnaire was used to collect general information and oral health behaviors. The Decayed, Missing, and Filled Teeth (DMFT) Index, International Caries Detection and Assessment System (ICDAS) II, caries prevalence, and rate of missing teeth were recorded via oral examination. Rank correlation was used to reveal the correlation between caries and oral health behavior. All of the pilots were men ages 21-58 yr (mean, 31.48 ± 7.20). In the caries group (CG), the frequency of tooth brushing and flossing was a little higher; more subjects had already given up smoking; more subjects had higher alcohol consumption; the sugar intake index (SII) was a little bit higher; and the last dental attendance time (LDAT) was shorter than that in the noncaries group (NCG). A total of 211 pilots (37.95%) had caries and 85 (15.29%) had missing teeth. The average DMFT was 2.19, while the mean ICDAS was 0.72. The frequency of sugary beverage consumption was negatively correlated with caries (r = -0.088), while a positive relationship was found between LDAT and caries (r = 0.094). Chinese civilian pilots have relatively good oral hygiene behavior and dental health. A relationship was found between sugary beverage consumption/LDAT and caries.
Military pilots are routinely exposed to environmental stressors such as hypoxia, dry air, and G-forces, which may affect pulmonary function. Although spirometry is performed regularly to assess flight fitness, the long-term effects of flying on lung function remain unclear. This retrospective study analyzed data from the Center for Man in Aviation of the Royal Netherlands Air and Space Force, encompassing two parts. First, all medical assessments from 2012 to early 2025 were reviewed to determine how often pilots were declared unfit to fly due to abnormal spirometry. Second, a Generalized Estimating Equation model was used to assess the effect of cumulative flight time, smoking status, and age on the forced expiratory volume in 1 s/vital capacity (FEV1/FVC) ratio using data collected between 2012 and mid-2019 (before the adoption of standardized Z-scores). Out of 9182 assessments, 3 pilots were deemed unfit to fly solely due to an abnormal spirometry. In the Generalized Estimating Equation analysis of 4558 assessments, flight hours showed a nonsignificant trend toward a positive, albeit clinically irrelevant, association with FEV1/FVC. There was no significant difference between aircraft types or between former and never-smokers. FEV1/FVC declined significantly with age and was significantly lower in current smokers compared to never-smokers. Pulmonary abnormalities rarely led to unfit declarations and no evidence was found for a negative long-term effect of military flying on pulmonary function. Age and smoking status were significant predictors of FEV1/FVC decline. These findings may inform future refinement of pulmonary assessment protocols for military pilots. Konings M, Wiekenkamp AC, Wingelaar-Jagt YQ, Wingelaar TT. Evaluating the impact of flight hours on pulmonary function in military pilots. Aerosp Med Hum Perform. 2025; 96(12):1079-1083.
At +1 Gz, electrical muscle stimulation (EMS) has been shown to increase systemic blood pressure similarly to a standard G-suit or lower body muscle straining. It was hypothesized that EMS might improve G protection at increased G levels. An EMS suit was developed with electrodes over the calves, thighs, gluteal, and abdominal muscles. Using nine subjects, the EMS suit was compared to a standard five-bladder G-suit during various G profiles up to +9 Gz in a human-rated centrifuge with EMS activated by electrical muscle stimulators at G levels at or above +4 Gz. The optimal EMS stimulation for a solid muscle contraction was determined for each muscle group in each subject prior to the G exposures. The mean maximal G level attained in the standard suit was 1.1 G higher during a relaxed gradual onset profile, 1.5 G higher during a relaxed rapid onset profile, and 2.0 G higher during a straining rapid onset profile when compared to the EMS suit. During a simulated aerial combat maneuver (SACM) ride, duration was 46 s longer with the standard suit compared to the EMS. During the SACM, the average heart rate was 23 bpm lower with the standard suit compared to EMS. All of the above differences were statistically significant. Finally, there were four G-LOCs with the EMS and none with the standard suit. The tested EMS suit did not give sufficient G protection at high Gs for pilots, nor substitute for a standard G-suit, as indicated by lower G protection and the episodes of G-LOC.
Flight deck alerts provide system malfunction information designed to lead corresponding pilot reactions aimed at guaranteeing flight safety. This study examined the roles of expertise and flight responsibility and their relationship to pilots' reactions to flight deck alerts. There were 17 pilots composing 12 flight crews that were assigned into pairs according to flight hours and responsibilities. The experiment included 9 flight scenarios and was carried out in a CRJ-200 flight simulator. Pilot performance was recorded by a wide angle video camera, and four kinds of reactions to alerts were defined for analysis. Pilots tended to have immediate reactions to uninterrupted cautions, with a turning off rate as high as 75%. However, this rate decreased sharply when pilots encountered interrupted cautions and warnings; they also exhibited many wrong reactions to warnings. Pilots with more expertise had more reactions to uninterrupted cautions than those with less expertise, both as pilot flying and pilot monitoring. Meanwhile, the pilot monitoring, regardless of level of expertise, exhibited more reactions than the pilot flying. In addition, more experienced pilots were more likely to have wrong reactions to warnings while acting as the monitoring pilot. These results suggest that both expertise and flight responsibility influence pilots' reactions to alerts. Considering crew pairing strategy, when a pilot flying is a less experienced pilot, a more experience pilot is suggested to be the monitoring pilot. The results of this study have implications for understanding pilots' behaviors to flight deck alerts, calling for specialized training and design of approach alarms on the flight deck.
Hot air ballooning incidents are relatively rare; however, when they do occur they are likely to result in a fatality or serious injury. Human error is commonly attributed as the cause of hot air ballooning incidents; however, error in itself is not an explanation for safety failures. This research aims to identify and establish the relative importance of factors contributing toward hot air ballooning incidents. Twenty-two Australian Ballooning Federation (ABF) incident reports were thematically coded using a bottom-up approach to identify causal factors. Subsequently, 69 balloonists (mean 19.51 yr experience) participated in a survey to identify additional causal factors and rate (out of 7) the perceived frequency and potential impact to ballooning operations of each of the previously identified causal factors. Perceived associated risk was calculated by multiplying mean perceived frequency and impact ratings. Incident report coding identified 54 causal factors within 9 higher level areas: Attributes, Crew Resource Management, Equipment, Errors, Instructors, Organizational, Physical Environment, Regulatory Body, and Violations. Overall, 'weather', 'inexperience,' and 'poor/inappropriate decisions' were rated as having greatest perceived associated risk. Although errors were nominated as a prominent cause of hot air ballooning incidents, physical environment and personal attributes are also particularly important for safe hot air ballooning operations. In identifying a range of causal factors, the areas of weakness surrounding ballooning operations have been defined; it is hoped that targeted safety and training strategies can now be put into place to remove these contributing factors and reduce the chance of pilot error.
There is a widely held belief that strenuous exercise should be avoided on arrival at high altitude (HA) and during acclimatization. Data from chamber studies are contradictory and the studies are usually of short duration, therefore differing from the "real world." We studied 48 trekkers during a 10-d ascent to 16,827 ft (5129 m) in the Cordillera Real area of Bolivia. Borg Rating of Perceived Exertion (RPE) scores were recorded for the hardest perceived exertion during the day after ascents to 12,576, 14,600, and 16,827 ft (3833, 4450, and 5129 m). Heart rate, Spo2, and Lake Louise Score (LLS) were recorded simultaneously. Statistical testing was performed using SPSS 21 software. A P-value of ≤ 0.05 was deemed significant. Acute mountain sickness (AMS) rates were higher after trekking days with higher levels of perceived exertion. The LLS was higher in those with a Borg RPE score ≥ 15 both following exercise (mean LLS 2.6 vs. 1.7) and at rest the following day (mean LLS 2.7 vs. 1.7). Heart rate was higher in those with high Borg RPE scores (80 vs. 87) and oxygen saturations lower at rest (86 vs. 83) the following morning. This data lends weight to the advice of moderate exertion during a trek to HA and suggests that reducing perceived exertion may reduce AMS.
Respiratory sinus arrhythmia (RSA) is characterized by normal fluctuations in heart rate in phase with the respiratory cycle. There are many proposed mechanisms underlying the RSA phenomenon, including respiratory-induced cardiac loading (i.e., Bainbridge reflex), arterial baroreflex activation, vagal feedback from pulmonary stretch receptors, and central neural mechanisms. It is currently unclear to what extent these mechanisms are responsible for eliciting RSA in humans, particularly in response to stressors. Here we present a case report of a healthy 26-yr-old woman (BMI 22.95 kg · m(-2)) who developed extreme RSA when exposed to the simultaneous cardiac loading stressors of 45° head-down tilt (HDT) and increased tidal volume during CO2 rebreathing. During baseline breathing in both supine and 45° HDT position, RSA magnitude was similar (mean ∼10-14 bpm). RSA was tidal volume-dependent, whereby in the supine position the RSA magnitude doubled with an approximate doubling in tidal volume during rebreathing (mean ∼20 bpm). However, when HDT and rebreathing were superimposed, extreme RSA was elicited (mean ∼45 bpm; range ∼38-110 bpm), approximately 450% over baseline breathing in the supine position. ECG analysis and follow up medical assessment revealed no underlying cardiac pathology. The existence of extreme RSA when HDT and increased inspired volumes were superimposed suggests that the dual cardiac loading stimuli acted synergistically, increasing RSA magnitude over either stimulus alone. This case report may be relevant to situations where orthostatic stress and augmented tidal volumes are superimposed, or more generally when conflicting sympathetic and parasympathetic activation is simultaneous.
Continuous positive airway pressure (CPAP) is used in air ambulances to treat patients with impaired oxygenation. Differences in mechanical principles between CPAP devices may affect their performance at different ambient air pressures, as will occur in an air ambulance during flight. Two different CPAP systems, a threshold resistor device and a flow resistor device, at settings of 5 and 10 cm H₂O were examined. Static pressure, static airflow, and pressure during simulated breathing were measured at ground level and at three different altitudes [2400 m (7874 ft), 3000 m (9843 ft), and 10,700 m (35,105 ft)]. When altitude increased, the performance of the two CPAP systems differed during both static and simulated breathing pressure measurements. With the threshold resistor CPAP, measured pressure levels were close to the preset CPAP level. Static pressure decreased 0.71 ± 0.35 cm H₂O at CPAP 10 cm H₂O compared to ground level and 35,105 ft (10,700 m). With the flow resistor CPAP, as the altitude increased, CPAP produced pressure levels increased. At 35,105 ft (10,700 m), the increase was 5.13 ± 0.33 cm H₂O at CPAP 10 cm H₂O. The velocity of airflow through the flow resistor CPAP device is strongly influenced by reduced ambient air pressure, leading to a higher delivered CPAP effect than the preset CPAP level. Threshold resistor CPAP devices seem to have robust performance regardless of altitude. Thus, the threshold resistor CPAP device is probably more appropriate for CPAP treatment in an air ambulance cabin, where ambient pressure will vary during patient transport.
Nitrogen (N2) in air causes cognitive impairment from gas narcosis when breathed at increased ambient pressures. This impairment might be reduced by using enriched air nitrox (EANx) mixtures, which have a higher oxygen and lower N2 content compared to air. This study aimed to investigate if divers differed in memory ability and self-assessment when breathing air and EANx30. The effect of depth (shallow vs. deep) and breathing gas (air vs. EANx30) on memory ability and subjective ratings of impairment was compared in 20 divers. Memory performance was significantly worse in deep water (Air: M = 22.1%, SD = 21.7%; EANx30: M = 22.1%, SD = 17.2%) compared to shallow water (Air: M = 29.2%, SD = 18.3%; EANx30: M = 33.3%, SD = 18.2%), but this impairment did not differ significantly between air and EANx30. Subjective ratings of impairment increased significantly from shallow water (Air: M = 5.2, SD = 5.9; EANx30: M = 3.0, SD = 4.4) to deep water (Air: M = 36.8, SD = 25.3; EANx30: M = 24.8, SD = 16.1) when breathing both air and EANx30. However, ratings were significantly lower when breathing EANx30 compared to air when in the deep water. It was concluded EANx30 does not reduce narcotic impairment over air. Additionally, divers were able to make a correct global self-assessment they were impaired by narcosis, but were unable to make a finer assessment, leading them to erroneously believe that EANx30 was less narcotic than air.
The T-10 parachute has been the U.S. Army standard parachute since 1952 and is now being replaced by the T-11, which has a capacity for heavier loads. This investigation compared injury rates between the two parachute systems during mass tactical parachute training exercises at Fort Bragg, NC. Investigators were on the drop zone for all parachute operations. Data on injured jumpers were collected on the drop zone and supplemented with medical records. Operational data were collected from standard reports and weather data were obtained using a Kestrel(®) Model 4500 pocket weather tracker. There were a total of 131,747 jumps resulting in 1101 injured service members for a crude incidence of 8.4 injuries/1000 jumps. Most injuries (88%) with a known injury mechanism were associated with ground impact. In univariate analysis, risk of injury with the T-10 was 9.1/1000 jumps and that with the T-11 was 5.2/1000 jumps [odds ratio (T-10/T-11) = 1.72, 95% confidence interval (95%CI) = 1.45-2.08, P < 0.01]. Other factors that independently increased injury risk included night jumps, combat loads, higher wind speeds, higher temperatures, certain aircraft, and entanglements. After controlling for these factors in a multivariate analysis, injury risk was still higher for the T-10 parachute when compared to the T-11 [odds ratio (T-10/T-11) = 1.56, 95%CI = 1.28-1.89, P < 0.01). For virtually all strata of the independent risk factors, the T-11 had a lower injury rate. Compared to the T-10, the T-11 parachute had a lower injury incidence under virtually all the operational conditions examined.
We evaluated ocular outcomes in a 14-d head-down tilt (HDT) bed rest (BR) study designed to simulate the effects of microgravity on the human body. Healthy subjects were selected using NASA standard screening procedures. Standardized NASA BR conditions were implemented (e.g., strict sleep-wake cycle, standardized diet, 24-hour-a-day BR, continuous video monitoring). Subjects maintained a 6° HDT position for 14 consecutive days. Weekly ophthalmological examinations were performed in the sitting (pre/post-BR) and HDT (in-bed phase) positions. Equivalency tests with optimal-alpha techniques evaluated pre/post-BR differences in best-corrected visual acuity (BCVA), spherical equivalent, intraocular pressure (IOP), Spectral-domain OCT retinal nerve fiber layer thickness (RNFLT), optic disc and macular parameters. 16 subjects (12 men and 4 women) were enrolled. Nearly all ocular outcomes were within our predefined clinically relevant thresholds following HDTBR, except near BCVA (pre/post-BR mean difference: -0.06 logMAR), spherical equivalent (-0.30 D), Tonopen XL IOP (+3.03 mmHg) and Spectralis OCT average (+1.14 μm), temporal-inferior (+1.58 μm) and nasal-inferior RNFLT (+3.48 μm). Modified Amsler grid, red dot test, confrontational visual field, and color vision were within normal limits throughout. No changes were detected on stereoscopic color fundus photography. A few functional and structural changes were detected after 14-d HDTBR, notably an improved BCVA possibly due to learning effect and RNFL thickening without signs of optic disc edema. In general, 6° HDTBR determined a small nonprogressive IOP elevation, which returned to baseline levels post-BR. Further studies with different BR duration and/or tilt angle are warranted to investigate microgravity-induced ophthalmological changes.
This study aimed to elucidate the overall risk and demographic/occupational predictors of neck pain among professional aviators. There were 413 surveys characterizing the severity and character of neck pain symptoms that were administered to a multinational cohort of pilots representing 3 separate airframe types. All results were compared to a nonaviator control group. Univariate and multivariate regression analyses were performed to elucidate independent predictors of occupationally related neck pain. Of the surveys, 92% were completed and returned. Multivariate analysis reveals that the pilot profession is independently predictive of increased occupational neck pain symptoms (OR 1.94, 95% CI 3.72, 1.01). High performance airframes, cargo/passenger airframes, and increasing age were also independent predictors of increased neck pain scores (OR = 3.91, 95% CI 7.10, 2.15; OR = 3.22, 95% CI 5.83, 1.77; OR = 4.00, 95% CI 7.43, 2.15, respectively). Our broad, multinational/multi-airframe analysis reveals that the pilot profession, most notably high performance and long-haul cargo/passenger airframes, display an increased risk of neck pain symptoms.
Maintaining intact cognitive performance is a high priority for space exploration. This review seeks to summarize the cumulative results of existing studies of cognitive performance in spaceflight and analogue environments. We focused on long-duration (>21 d) studies for which no review has previously been conducted. There were 11 published studies identified for long-duration spaceflight (N = 42 subjects) as well as 21 shorter spaceflight studies (N = 70 subjects). Overall, spaceflight cognitive studies ranged from 6-438 d in duration. Some 55 spaceflight analogue studies were also identified, ranging from 6 to 520 d. The diverse nature of experimental procedures and protocols precluded formal meta-analysis. In general, the available evidence fails to strongly support or refute the existence of specific cognitive deficits in low Earth orbit during long-duration spaceflight, which may be due in large part to small numbers of subjects. The studies consistently suggest that novel environments (spaceflight or other) induce variable alterations in cognitive performance across individuals, consistent with known astronaut experiences. This highlights the need to better quantify the magnitude and scope of this interindividual variability, and understand its underlying factors, when predicting in-flight cognitive functioning for extended periods.