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Objectives Explore the impact transitioning from daytime to nighttime operations has on performance in U.S. Army Rangers. Methods Fifty-four male Rangers (age 26.1 ± 4.0 years) completed the Y-Balance Test (YBT), a vertical jump assessment, and a grip strength test at three time points. Baseline testing occurred while the Rangers were on daytime operations; post-test occurred after the first night into the nighttime operation training (after full night of sleep loss), and follow-up testing occurred six days later (end of nighttime training). Results On the YBT, performance was significantly worse at post-test compared to baseline during right posteromedial reach (104.1 ± 7.2 cm vs 106.5 ± 6.7 cm, p = .014), left posteromedial reach (105.4 ± 7.5 cm vs 108.5 ± 6.6 cm, p = .003), right composite score (274.8 ± 19.3 cm vs 279.7 ± 18.1 cm, p = .043), left composite score (277.9 ± 18.1 cm vs 283.3 ± 16.7 cm, p = .016), and leg asymmetry was significantly worse in the posterolateral direction (4.8 ± 4.0 cm vs 3.7 ± 3.1 cm, p = .030) and the anterior direction (5.0 ± 4.0 cm vs 3.6 ± 2.6 cm, p = .040). The average vertical jump height was significantly lower at post-test compared to baseline (20.6 ± 3.4 in vs 21.8 ± 3.0 in, p = .004). Baseline performance on YBT and vertical jump did not differ from follow-up. Conclusions Army Rangers experienced an immediate, but temporary, drop in dynamic balance and vertical jump performance when transitioning from daytime to nighttime operations. When feasible, Rangers should consider adjusting their sleep cycles prior to anticipating nighttime operations in order to maintain their performance levels. Investigating strategies that may limit impairments during this transition is warranted.

To examine the sleep health of incoming Army trainees and how it is impacted during basic combat training (BCT).Prospective.BCT site (Fort Jackson, SC).A total of 1349 trainees (936 = male, 413 = female, 20.73 ± 3.67 years).Participants completed the Pittsburgh Sleep Quality Index (PSQI), the Morningness/Eveningness Questionnaire, and the Epworth Sleepiness Scale at the start of BCT and a modified PSQI at the end of BCT.At baseline, trainees reported an average sleep duration of 7.65 ± 1.68 hours per night, with 81.8% rating their sleep quality as "Very Good or Fairly Good." The mean reported Morningness/Eveningness Questionnaire score was 50.63 ± 8.11 and the mean Epworth Sleepiness Scale was 8.60 ± 4.02. Reported sleep duration was significantly less during BCT (6.73 ± 0.90 hours) compared to baseline (P.001). There was no significant difference in the mean PSQI Global score at the end of BCT compared to the start (5.33 ± 3.00 vs. 5.42 ± 2.85, P = .440), however, 6 of the 7 component scores were significantly different (with Sleep Quality, Sleep Duration, and Daytime Dysfunction scores being higher/worse and Sleep Latency, Sleep Efficiency, and Sleep Medication Use scores being lower/improved [all P.01]).Army BCT trainees in this large sample reported good sleep health characteristics at entry to training, including achieving recommended sleep amounts (7 hours per night) and reporting good sleep quality. During BCT, negative changes were observed in reported sleep duration and quality in trainees. Further investigation into the factors contributing to changes in trainees' sleep health during BCT and the implications on subsequent readiness, injury risk, and performance is warranted.

OBJECTIVE To examine relationships between percent body fat (%BF) and total energy expenditure (TEE) on permethrin exposure among Army National Guard (ARNG) Soldiers wearing permethrin-treated uniforms. METHODS ARNG members (n = 47) participated in a 9-day study. Repeated body composition (height, weight, %BF) measurements and daily urine samples, analyzed for permethrin and N,N-diethyl-meta-toluamide (DEET) metabolites, were collected. TEE was determined via doubly labeled water protocol. Linear mixed and regression models were used for analyses. RESULTS Neither %BF nor TEE were significantly associated with permethrin or DEET biomarkers. However, a significant interaction effect (F = 10.76; P = 0.0027) between laundering history and %BF was observed; 10% higher %BF was significantly associated with 25% higher permethrin biomarker concentrations among those wearing uniforms washed less than or equal to 25 (compared with more than 25) times. CONCLUSIONS Uniform laundering history significantly affects the association between %BF and permethrin-treated uniform exposure.

Background Thirty years ago, Gulf War (GW) veterans returned home with numerous health symptoms that have been associated with neurotoxicant exposures experienced during deployment. The health effects from these exposures have been termed toxic wounds. Most GW exposure-outcome studies utilize group analyses and thus individual fluctuations in symptoms may have been masked. This study investigates health symptom trajectories in the same veterans over 25 years. Methods Veterans were categorized into 5 a priori trajectory groups for each health symptom and Chronic Multisymptom Illness (CMI) clinical case status. Multinomial logistic regression models were used to investigate associations between these trajectories and neurotoxicant exposures. Results Results indicate that more than 21 Pyridostigmine Bromide (PB) pill exposure was associated with consistent reporting of fatigue, pain, and cognitive/mood symptoms as well as the development of six additional symptoms over time. Chemical weapons exposure was associated with both consistent reporting and development of neurological symptoms over time. Reported exposure to tent heater exhaust was associated with later development of gastrointestinal and pulmonary symptoms. Veterans reporting exposure to more than 21 PB pills were more than 8 times as likely to consistently meet the criteria for CMI over time. Conclusion This study highlights the importance of the continued documentation of the health impacts experienced by GW veterans’, their resulting chronic health symptoms, and the importance of exposure-outcome relationships in these veterans now 30 years post-deployment.

This study examined the effect of high-temperature conditions and uniform wear time durations (expeditionary, 33 h continuous wear; garrison, 3 days, 8 h/day wear) on permethrin exposure, assessed by urinary permethrin biomarkers, from wearing post-tailored, factory-treated military uniforms. Four group study sessions took place over separate 11-day periods, involving 33 male Soldiers. Group 1 (n = 10) and Group 2 (n = 8) participants wore a study-issued permethrin-treated Army uniform under high heat environment (35 °C, 40% relative humidity (rh)) and expeditionary and garrison wear-time conditions, respectively. For comparison, Group 3 (n = 7) and Group 4 (n = 8) participants wore study-issued permethrin-treated uniforms in cooler ambient conditions under operational and garrison wear-time conditions, respectively. Urinary biomarkers of permethrin (3-phenoxybenzoic acid, and the sum of cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid) were significantly higher under high temperature compared to ambient conditions, regardless of wear-time situations (Group 1 vs. Group 3; Group 2 vs. Group 4; p < 0.001, for both). Under high-temperature conditions, expeditionary (continuous) compared to garrison wear-time resulted in significantly (p < 0.001) higher urinary biomarker concentrations (Group 1 vs. Group 2). Differences related to wear-time under the ambient conditions (Group 3 vs. Group 4) were not statistically significant. Findings suggest that wearing permethrin-treated clothing in heat conditions results in higher internal dose of permethrin above that observed under ambient conditions.

Stress fractures are common in military personnel and endurance athletes, and nonsteroidal anti‐inflammatory drug (NSAID) use is widespread in these populations. NSAIDs inhibit prostaglandin synthesis, which blunts the anabolic response of bone to physical activity and could therefore increase risk of stress fracture. The objective of this study was to determine whether prescribed NSAIDs were associated with stress fracture diagnoses among US Army soldiers. We also aimed to establish whether acetaminophen, an analgesic alternative to NSAIDs, was associated with stress fracture risk. A nested case‐control study was conducted using data from the Total Army Injury and Health Outcomes Database from 2002 to 2011 (n = 1,260,168). We identified soldiers with a diagnosis of stress fracture (n = 24,146) and selected 4 controls per case matched on length of military service (n = 96,584). We identified NSAID and acetaminophen prescriptions 180 to 30 days before injury (or match date). We also identified soldiers who participated in basic combat training (BCT), a 10‐week period of heightened physical activity at the onset of Army service. Among these individuals, we identified 9088 cases and 36,878 matched controls. Conditional logistic regression was used to calculate incident rate ratios (RR) for stress fracture with adjustment for sex. NSAID prescription was associated with a 2.9‐fold increase (RR = 2.9, 95% confidence interval [CI] 2.8–2.9) and acetaminophen prescription with a 2.1‐fold increase (RR = 2.1, 95% CI 2.0–2.2) in stress fracture risk within the total Army population. The risk was more than 5‐fold greater in soldiers prescribed NSAIDs (RR = 5.3, 95% CI 4.9–5.7) and more than 4‐fold greater in soldiers prescribed acetaminophen (RR = 4.4, 95% CI 3.9–4.9) during BCT. Our results reveal an association between NSAID and acetaminophen prescriptions and stress fracture risk, particularly during periods of heightened physical activity. Prospective observational studies and randomized controlled trials are needed to support these findings before clinical recommendations can be made. © 2018 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR).

Objective This analysis examined the relationship between Gulf War (GW) exposures and health symptoms reported in three time periods over 20 years in Ft. Devens Cohort veterans. Methods Repeated logistic regression models examined the association of exposures and health symptoms over time. Models included baseline age, active duty status, post-traumatic stress disorder status, sex, and time since deployment as covariates. Results Exposure to tent heaters was associated with increased odds of crying easily and muscle twitching. Exposure to pyridostigmine bromide (PB) pills was associated with increased odds of depression and fatigue. Exposure to the Khamisiyah sarin plume was associated with increased odds of trouble concentrating and crying easily. Conclusion This longitudinal analysis demonstrated an association between neurotoxicant exposures and increased odds of cognitive/mood, fatigue, and neurological symptoms. In addition, most symptoms increased over time since deployment regardless of exposure.

U.S. Army Basic Combat Training (BCT) prepares new recruits to meet soldier physical demands. It also serves as a model of physical changes in healthy young nonobese women and men during an intensive 10-week training program without diet restriction. In this prospective observational study, we quantified the changes in lean mass and body fat induced by BCT in a large sample of men and women undergoing the same physical training program.Young women (n = 573) and men (n = 1071) meeting Army health and fitness recruitment standards volunteered to provide DXA-derived body composition data at the beginning and end of BCT.During BCT, there was no change in body mass in women and a 1.7-kg loss in men. Relative body fat (%BF) declined by an average of 4.0 ± 2.4 and 3.4 ± 2.8 percentage points (±SD) for women and men, respectively. The greatest predictor of change in %BF during BCT for both sexes was %BF at the beginning of training. Women and men gained an average 2.7 ± 1.6 kg and 1.7 ± 2.0 kg of lean mass during BCT.Army BCT produced significant effects on body composition despite minimal changes in total body mass. These findings demonstrate the ability of a 10-week sex-integrated physical training program to positively alter body composition profiles of young adults.

Many veterans of the Iraq and Afghanistan Wars have experienced traumatic brain injury (TBI). Although prior work has examined associations between TBI and development of psychiatric syndromes, less is known about associations between TBI and component emotions constituting these syndromes, especially in the long term. The purpose of this study was to examine the long-term emotional consequences of deployment-related TBI.As part of VA Cooperative Studies Program #566, we assessed a sample ofWarzone TBI events, particularly when greater than mild in severity, were independently associated with depression, anxiety, and stress severity at long-term follow-up, even after taking into account variance attributable to pre-deployment emotional distress and war-zone stress. Post-hoc analyses did not detect independent associations of either number of events or injury mechanism with outcomes.These findings highlight the potentially enduring and multi-faceted emotional effects of deployment TBI, underscoring the need for early assessment of negative affectivity in warzone veterans reporting TBI.

Environmental factors, including high temperature and humidity, can influence dermal absorption of chemicals. Soldiers can be dermally exposed to permethrin while wearing permethrin-treated uniforms. This study aimed at examining the effects of high temperature and a combined high temperature and humid environment on permethrin absorption compared with ambient conditions when wearing a permethrin-treated uniform. Twenty-seven male enlisted soldiers wore study-issued permethrin-treated army uniforms for 33 consecutive hours in three different environments: 1) simulated high temperature (35°C, 40% relative humidity [rh]) (n = 10), 2) simulated high temperature and humidity (30°C, 70% rh) (n = 10), and 3) ambient conditions (13°C, 60% rh) (n = 7). Spot urine samples, collected at 21 scheduled time points before, during, and after wearing the study uniforms, were analyzed for permethrin exposure biomarkers (3-phenoxybenzoic acid, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid) and creatinine. Biomarker concentrations were 60-90% higher in the heat and combined heat/humidity groups (P < 0.001-0.022) than the ambient group. Also, the average daily permethrin dose, calculated 12 hours after removing the treated uniforms, was significantly higher in the heat (P = 0.01) and the heat/humidity (P = 0.03) groups than the ambient group. There were no significant differences in biomarker concentrations or computed average daily dose between the heat and the heat/humidity groups. Both hot and combined hot and humid environmental conditions significantly increased permethrin absorption in soldiers wearing permethrin-treated uniforms.

Background Rates of lower extremity musculoskeletal injury are reportedly higher in professional and collegiate athletes following concussions. However, there is a paucity of evidence on this relationship in individuals who are not high-level athletes. Objectives To examine the risk of acute lower extremity musculoskeletal injury in soldiers within 2 years of an incident concussion, compared to matched nonconcussed soldiers. Methods This was a matched-cohort study that used the medical encounter and personnel data of active-duty US Army soldiers from 2005 to 2011. Incident concussions were identified using International Classification of Diseases-Ninth Revision codes in medical encounter data of all soldiers from 2005 to 2009. One nonconcussed soldier in the US Army during the same month was matched by age, sex, rank, length of service, deployment status, and military career field to each concussed soldier. Hazard ratio (HR) and 95% confidence interval (CI) were calculated for the risk of lower extremity injury within 2 years of the incident concussion. Monthly HRs were compared to identify differences in injury rates between the groups, and an HR for the period of greatest difference was also calculated. Results A total of 23 044 individuals (11 522 concussed and 11 522 nonconcussed) were included in the study. Within 2 years of concussion, the hazard of lower extremity injury was 38% greater in concussed compared to nonconcussed soldiers (HR, 1.38; 95% CI: 1.30, 1.46), while the 15-month hazard was 45% greater (HR, 1.45; 95% CI: 1.36, 1.56). Conclusion The rate of lower extremity musculoskeletal injury among this population of physically active adults is higher following concussion, and the risk remains elevated for more than a year following injury. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2018;48(7):533-540. Epub 8 May 2018. doi:10.2519/jospt.2018.8053.

The purpose of this study was to determine the association of mild traumatic brain injury (mTBI) with subsequent post-traumatic stress disorder (PTSD) and mental health disorders (MHD), and the intervening role of acute stress disorder (ASD). This matched case-control study utilized the Total Army Injury and Health Outcomes Database (TAIHOD) to analyze soldiers' (n = 1,261,297) medical encounter data between 2002 and 2011. International Classification of Diseases, Ninth Revision (ICD-9) codes were used to identify: mTBI (following Centers for Disease Control [CDC] surveillance definition for mTBI), MHD (ICD-9 codes for depression and anxiety, excluding PTSD), PTSD (ICD-9 309.81), and ASD (ICD-9 308.3). Incident cases of mTBI (n = 79,505), PTSD (n = 71,454), and MHD (n = 285,731) were identified. Overall incidence rates per 1000 soldier years were: mTBI = 17.23, PTSD = 15.37, and MHD = 67.99. mTBI was associated with increased risk for PTSD (risk ratio [RR] 5.09, 95% confidence interval [CI] 4.82-5.37) and MHD (RR 2.94, 95% CI 2.84-3.04). A sub-analysis of the mTBI-only soldiers found that a diagnosis ASD, compared with a diagnosis of no ASD, was associated with greater risk for subsequent PTSD (RR 2.13, 95% CI 1.96-2.32) and MHD (RR 1.90, 95% CI 1.72-2.09) following mTBI. Results indicate that soldiers with previous mTBI have a higher risk for PTSD and MHD, and that ASD may also mediate PTSD and MHD risk subsequent to mTBI. These data may help guide important surveillance and clinical rehabilitation considerations for high-risk populations.

Background Musculoskeletal injuries (MSKIs) are common in military trainees and present a considerable threat to occupational fitness, deployability, and overall military readiness. Despite the negative effects of MSKIs on military readiness, comprehensive evaluations of the key known and possible risk factors for MSKIs are lacking. The U.S. Army Research Institute of Environmental Medicine (ARIEM) is initiating a large-scale research effort, the ARIEM Reduction in Musculoskeletal Injury (ARMI) Study, to better understand the interrelationships among a wide range of potential MSKI risk factors in U.S. Army trainees in order to identify those risk factors that most contribute to MSKI and may be best targeted for effective mitigation strategies. Methods This prospective study aims to enroll approximately 4000 (2000 male and 2000 female) U.S. Army trainees undergoing Basic Combat Training (BCT). Comprehensive in-person assessments will be completed at both the beginning and end of BCT. Participants will be asked to complete surveys of personal background information, medical history, physical activity, sleep behaviors, and personality traits. Physical measurements will be performed to assess anthropometrics, tibial microarchitecture and whole body bone mineral density, muscle cross-sectional area, body composition, and muscle function. Blood sampling will be also be conducted to assess musculoskeletal, genetic, and nutritional biomarkers of risk. In addition, participants will complete weekly surveys during BCT that examine MSKI events, lost training time, and discrete risk factors for injury. Participants’ medical records will be tracked for the 2 years following graduation from training to identify MSKI events and related information. Research hypotheses focus on the development of a multivariate prediction model for MSKI. Discussion Results from this study are expected to inform current understanding of known and potential risk factors for MSKIs that can be incorporated into solutions that optimize Soldier health and enhance military readiness.

The mental health toll of the Iraq and Afghanistan Wars on military veterans has been considerable, yet little is known about the persistence of these adverse outcomes, especially relative to predeployment status. We prospectively examined posttraumatic stress disorder (PTSD) as a long-term consequence of warzone deployment, integrating data collected from 2003-2014. In the Neurocognition Deployment Health Study, we measured PTSD symptoms in US Army soldiers before and shortly after Iraq War deployment. We used the PTSD Checklist-Civilian Version and a structured clinical interview (i.e., Clinician-Administered PTSD Scale) to reassess PTSD in 598 service members and military veterans a median of 7.9 years (interquartile range, 7.2-8.5 years) after an index Iraq deployment. At long-term follow-up, 24.7% (95% confidence interval (CI): 21.5, 28.4) of participants met the case definition for PTSD, which was an absolute increase of 14.2% from the percentage assessed postdeployment (10.5%; 95% CI: 7.8, 13.7) and of 17.3% from the percentage assessed predeployment (7.4%; 95% CI: 5.5, 9.8). These findings highlight that PTSD is an enduring consequence of warzone participation among contemporary military personnel and veterans. The largest increase in PTSD cases occurred between the postdeployment and long-term follow-up assessments, which suggests that adverse stress reactions cannot necessarily be expected to dissipate over time and actually may increase.

BACKGROUND: Traumatic brain injury (TBI) was not considered to be common in the 1990-1991 Gulf War (GW). Therefore, the relationship between TBI and chronic health symptoms experienced by GW veterans is unknown. Health symptoms reported by veterans deployed more recently to this region (Operations Enduring and Iraqi Freedom) are similar to those of GW veterans and have been primarily attributed to TBI. OBJECTIVE: To examine the relationships among self-reported TBI, health symptoms, chronic multisymptom illness (CMI), and health-related quality of life among GW veterans. PARTICIPANTS: Participants included 1 274 GW veterans from the Devens Cohort Study, 156 of whom self-reported a history of TBI (12.2% of the sample). DESIGN: Cross-sectional retrospective analysis of existing survey data. MAIN MEASURES: A 52-item health symptom checklist and the RAND 36-Item Health short Form Survey. RESULTS: Self-reported TBI in GW Veterans is related to increased rates of health symptoms, CMI, and poorer health-related quality of life. CONCLUSIONS: Gulf War veterans' self-reported exposure to TBI is related to increased rates of chronic health symptoms and CMI, which interfere with everyday activities of daily living. Language: en

OBJECTIVE: This study aimed to evaluate blood volatile organic compound (VOC) levels as biomarkers of occupational jet propulsion fuel 8 (JP-8) exposure while controlling for smoking. METHODS: Among 69 Air Force personnel, post-shift blood samples were analyzed for components of JP-8, including ethylbenzene, toluene, o-xylene, and m/p-xylene, and for the smoking biomarker, 2,5-dimethylfuran. JP-8 exposure was characterized based on self-report and measured work shift levels of total hydrocarbons in personal air. Multivariate regression was used to evaluate the relationship between JP-8 exposure and post-shift blood VOCs while controlling for potential confounding from smoking. RESULTS: Blood VOC concentrations were higher among US Air Force personnel who reported JP-8 exposure and work shift smoking. Breathing zone total hydrocarbons was a significant predictor of VOC blood levels, after controlling for smoking. CONCLUSIONS: These findings support the use of blood VOCs as a biomarker of occupational JP-8 exposure.

Permethrin is used to treat clothing as a personal protective measure against insect bites in military and recreational settings, and along with other pyrethroid insecticides, is sprayed in agricultural and residential sites for pest control. The widespread use of permethrin and other pyrethroid insecticides creates a potential for human exposure in occupational and non-occupational populations. This study aims to compare urinary biomarkers of pyrethroid exposure in two US military cohorts to the general US adult population from the 2009-2010 Nutritional Health and Nutrition Examination Survey (NHANES). Additional comparisons are made to previously published biomonitoring data from occupational and population cohort studies. Urine samples from two US military cohorts were analyzed for 3 permethrin metabolites: 3-phenoxybenzoic acid (3-PBA), and cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DCCA). Biomarker concentrations were adjusted for creatinine. Geometric means were calculated and then compared to creatinine-adjusted concentrations of 3-PBA and trans-DCCA in US adults (aged 20-59) using data collected as part of the 2009-2010 NHANES. Sex- and race-standardized geometric means were calculated separately for each of the US military groups using the demographic distributions from NHANES 2009-2010. Data from other military, occupational, and non-occupational population studies were extracted from the literature for further comparison. The two US military cohorts' geometric mean values, non-standardized and standardized, were markedly higher than what was observed in the general US adult population. Biomarkers of permethrin exposure were detected at a high frequency in military personnel wearing treated uniforms (90-100%). Detection rates of these biomarkers were similarly high in other studies of occupational exposure (67-100%) to pyrethroid insecticides. Adjusting for creatinine, the concentrations observed in the military groups were generally higher than levels seen in the general US adult population (NHANES, 2009-2010), other occupational groups (e.g., farmworkers, flight attendants, and pest control workers), and population cohorts from other countries.

Objectives: Military deployment is associated with increased risk of adverse emotional and cognitive outcomes. Longitudinal associations involving posttraumatic stress disorder (PTSD), relatively mild traumatic brain injury (TBI), and neurocognitive compromise are poorly understood, especially with regard to long-term outcomes, and rigorous research is necessary to better understand the corresponding relationships. The objective of this study was to examine short-term and long-term (>5 years) longitudinal associations among PTSD, neurocognitive performance, and TBI following military deployment. Methods: In this prospective study, N=315 U.S. Army soldiers were assessed at military installations before (2003–2005) and after (2004–2006) an index deployment to the Iraq War, and again an average of 7.6 years later (2010–2014) as a nationally dispersed cohort of active duty soldiers, reservists, and veterans. Thus, the study design allowed for two measurement intervals over which to examine changes. All assessments included the PTSD Checklist, civilian version, and individually-administered performance-based neurocognitive tests. TBI history was derived from clinical interview. Results: Autoregressive analyses indicated that visual reproduction scores were inversely related to subsequent PTSD symptom severity at subsequent assessments. Conversely, increases in PTSD symptom severity over each measurement interval were associated with poorer verbal and/or visual recall at the end of each interval, and less efficient reaction time at post-deployment. TBI, primarily mild in this sample, was associated with adverse PTSD symptom outcomes at both post-deployment and long-term follow-up. Conclusions: These results suggest longitudinal relationships among PTSD symptoms, TBI, and neurocognitive decrements may contribute to sustained emotional and neurocognitive symptoms over time. (JINS, 2018, 24, 311–323)

To examine military, demographic, and psychosocial predictors of military retention following operational deployment.Military status 12 months following return from Iraq deployment was assessed via service records in 740 regular active duty Army Soldiers. Potential predictors of military retention were derived from prospectively administered in-person interviews and questionnaires conducted within 3 months following return from Iraq.At 12 months following return from deployment, 18.1% (n = 134) of the sample had separated from military service. Cox proportional hazards analyses, adjusting for demographic, military, and psychosocial predictors, identified several factors that were independently associated with military attrition: less than (vs. equal to or more than) 6 years military experience (hazards ratio [HR], 3.98; 95% CI, 2.12-7.45); unmarried (vs. married) status (HR, 1.51; 95% CI, 1.06-2.16); and lower (vs. higher) levels of self-reported unit support during deployment (HR, 2.22; 95% CI, 1.42-3.47).Service members early in their career may be especially prone to military attrition. With regard to military retention, our findings suggest that it may be particularly important to develop initiatives that target organizational cohesion and support.

The long-term mental health effects of war-zone deployment in the Iraq and Afghanistan wars on military personnel are a significant public health concern. Using data collected prospectively at three distinct assessments during 2003-2014 as part of the Neurocognition Deployment Health Study and VA Cooperative Studies Program Study #566, we explored how stress exposures prior, during, and after return from deployment influence the long-term mental health outcomes of posttraumatic stress disorder (PTSD), depression, anxiety disorders, and problem drinking. Longer-term mental health outcomes were assessed in 375 service members and military veterans an average of 7.5 years (standard deviation = 1.0 year) after the initial (i.e., "index") Iraq deployment following their predeployment assessment. Anxiety disorder was the most commonly observed long-term mental health outcome (36.0%), followed by depression (24.5%), PTSD (24.3%), and problem drinking (21.0%). Multivariable regression models showed that greater postdeployment stressors, as measured by the Post-Deployment Life Events scale, were associated with greater risk of depression, anxiety disorders, and problem drinking. Anxiety disorder was the only outcome affected by predeployment stress concerns. In addition, greater postdeployment social support was associated with lower risk of all outcomes except problem drinking. These findings highlight the importance of assessing postdeployment stress exposures, such as stressful or traumatic life events, given the potential impact of these stressors on long-term mental health outcomes. This study also highlights the importance of postdeployment social support as a modifiable protective factor that can be used to help mitigate risk of long-term adverse mental health outcomes following war-zone exposure.

Petroleum-based fuels such as jet propellant (JP) 4, JP5, JP8, and jet A1 (JetA) are among the most common occupational chemical exposures encountered by military and civilian workforces. Although acute toxicity following high-level exposures to JP8 and similar chemical mixtures has been reported, the relationship between persistent low-level occupational exposures to jet fuels and both acute and longer-term central nervous system (CNS) function has been comparatively less well characterized. This paper describes results of neurocognitive assessments acquired repeatedly across a work week study design (Friday to Friday) as part of the Occupational JP8 Exposure Neuroepidemiology Study (OJENES) involving U.S. Air Force (AF) personnel with varying levels of exposure to jet fuel (JP8). JP8 exposure levels were quantified using both personal air monitoring and urinary biomarkers of exposure. Neurocognitive performance was evaluated using an objective, standardized battery of tests. No significant associations with neurocognitive performances were observed between individuals having regular contact and those with minimal/no direct contact with JP8 (measured by average work week levels of personal breathing zone exposure). Also, no significant findings were noted between repeated measures of absorbed dose (multi-day pre-shift urinary 1- and 2-naphthol) and reduced proficiency on neurocognitive tasks across the work week. Results suggest that occupational exposure to lower (than regulated standards) levels of JP8 do not appear to be associated with acute, measurable differences or changes in neurocognitive performance.

To evaluate the association between inhalation exposure to jet propulsion fuel 8 (JP-8) and urinary metabolites among US Air Force (USAF) personnel, and investigate the role of glutathione S-transferase polymorphisms.Personal air samples were collected from 37 full-time USAF personnel during 4 consecutive workdays and analyzed for JP-8 constituents and total hydrocarbons. Pre- and postshift urine samples were collected each day and analyzed for polycyclic aromatic hydrocarbon urinary metabolites.Work shift exposure to total hydrocarbons was significantly associated with postshift urinary 1-naphthol (β = 0.17; P =0.0001), 2-naphthol (β = 0.09; P = 0.005), and 2-hydroxyfluorene concentrations (β = 0.08; P = 0.006), and a significant gene-environment interaction was observed with glutathione S-transferase mu-1.USAF personnel experience inhalation exposure to JP-8, which is associated with absorption of JP-8 constituents while performing typical job-related tasks, and in our data the glutathione S-transferase mu-1 polymorphism was associated with differential metabolism of naphthalene.

The objective of the project was to ascertain whether urinary biomarkers of permethrin exposure are detected after wearing post-tailored, fabric-treated military uniforms under two different wear-time exposure scenarios. Study A occurred over 3.5 days and involved six participants wearing treated uniforms continuously for 30-32 h. Urine collection occurred at scheduled time points before, during, and after wearing the uniform. Study B, conducted over 19 days, included 11 participants wearing treated uniforms for 3 consecutive days, 8 h each day (with urine collection before, during, and after wear). Urinary biomarkers of permethrin (3-phenoxybenzoic acid (3PBA), cis- 2,2-(dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cDCCA), trans- 2,2-(dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (tDCCA)) were detected during and after wear. Biomarker detection generally occurred over the 10- to 12-h period after putting on the uniform and subsided 24 h following uniform removal (in both Study A and B scenarios). Those wearing permethrin-treated uniforms under the longer wear-time scenario (Study A) excreted significantly higher cumulative mean levels compared with those in Study B (3.29 times higher for 3PBA and 2.23 times higher for the sum of c/tDCCA (P≤0.001)). Findings suggest that wearing permethrin-treated clothing does increase absorbed, internal dose levels of permethrin above population levels and is significantly related to wear-time duration.

The objective of this study was to describe trends in the diagnostic rates for anxiety disorders (ADs) types in the U.S. military from 2000 to 2009. Data for the numbers of diagnosed cases for the first documented occurrence of ADs during ambulatory visits while serving in the military were obtained from the Defense Medical Epidemiology Database for all active duty service members and examined across branch of service and by gender. Results indicate that Anxiety Not Otherwise Specified (ANOS) was the most frequently diagnosed AD type in each of the 10 years between 2000 and 2009, with an average rate of 0.8 per 100 service members for first service occurrence, followed by PTSD at a rate of 0.5 out of every 100. Starting in 2002, the yearly first occurrence rates of ANOS and PTSD were significantly higher (p

Measurement of stress exposure is central to understanding military mental health outcomes. Although temporal stability of combat event reporting has been examined, less is known about the stability of reporting for noncombat events in military samples. Objectives are to examine consistency in reporting stressful life events in nondeployed U.S. Army soldiers and its association with posttraumatic stress disorder (PTSD) symptomatology.Examined reporting consistency over approximately 8 months among 466 soldiers. Regression models examined factors associated with decreased, increased, and stable reporting.Stability of the number of events endorsed over time was high. However, item-level agreement was slight to moderate (kappas: .13-.54), with inconsistencies due primarily to decreased reporting. After adjusting for covariates and initial PTSD, second assessment PTSD was associated with increased and stable reporting.Inconsistent reporting extends beyond combat events to other stressful life events in military personnel and is associated with PTSD.

This study evaluated associations between pre-deployment neurocognitive performance and post-deployment posttraumatic stress disorder (PTSD) symptoms in a sample of deployed active duty Army soldiers. As part of a larger longitudinal study, each participant completed baseline measures of memory, executive attention, and response inhibition, and baseline and post-deployment self-report measures of PTSD symptom severity. Data were subjected to multiple regression analyses that examined associations between baseline neurocognitive performances and longitudinal PTSD symptom outcome. Results revealed that pre-trauma immediate recall of visual information was associated with post-deployment PTSD symptom severity, even after controlling for pre-deployment PTSD symptom levels, combat intensity, age, gender, and test-retest interval. There was also an interaction between pre-deployment PTSD symptom severity and pre-deployment immediate visual recall and verbal learning, indicating that neurocognitive performances were more strongly (and negatively) associated with residualized post-deployment PTSD symptoms at higher levels of pre-deployment PTSD symptoms. These findings highlight the potential role of pre-trauma neurocognitive functioning in moderating the effects of trauma exposure on PTSD symptoms.(JINS, 2009, 15, 840–852.)

The U.S. Department of Defense invested $150 M to investigate undiagnosed Gulf War Illnesses (GWI) and twice that amount in post hoc clinical management. No new disease syndrome was identified, but the research produced new understanding and awareness of important psychosocial and neurotoxicological interactions that represented a difficult and relatively untapped frontier in biomedical research, especially concerning chronic multisymptom illnesses. Some specific Gulf War issues such as effects of depleted uranium, Leishmania diagnosis and treatment, and pesticide and prophylactic drug interactions have been intensively investigated; remaining priorities for further investigation include: markers of neurologic change (e.g., neuroimaging, neuropsychological testing), interactions between psychological resilience and neurotoxicity, structure-function relationships of neurotoxins with neurodegenerative disease potential, and predictors of individual susceptibility. The primary conclusions from the program are that no specific neurotoxic chemical has been identified that explains the chronic multisymptom illness observed but wellness of service members in future deployments may be better sustained based on continuing research on preexposure health baselining, fitness and health-damaging behaviors, and stress resilience. The many scientific discoveries and accomplishments of the GWI research effort have advanced military medical science, provided a solid basis on which to build future protections against health and performance risks to the warfighter, and improved the ability to respond to future deployment health issues.

This study examined interrelationships among combat exposure, symptoms of posttraumatic stress disorder (PTSD), and family adjustment in a sample of male and female Operation Desert Storm veterans (N = 1,512). In structural equation models for both male and female veterans, higher combat exposure was associated with higher PTSD symptoms, which in turn were associated with poorer family adjustment, although these indirect effects did not reach statistical significance. The model for female veterans evidenced a significant direct negative association between combat exposure and family adjustment when it statistically accounted for PTSD symptoms. When the relative impacts of separate PTSD symptom groupings were examined, those reflecting withdrawal/numbing symptoms and arousal/lack of control symptoms significantly and indirectly accounted for the negative effects of combat exposure on family adjustment. Study findings indicate a number of possible pathways through which war-zone deployments negatively impact military families and suggest several avenues for future research.

Information on the mental status of soldiers operating at the limits of human tolerance will be vital to their management in future deployments; it may also allow earlier intervention for conditions such as undiagnosed Gulf War illnesses and Parkinson's Disease. The Army needs a parsimonious set of neuropsychological tests that reliably identify subtle changes for: (1) early detection of individual health and military performance impairments and (2) management of occupational and deployment health risks. Testing must characterize cognitive lapses in healthy individuals faced with relevant operational stressors (i.e., anxiety, information overload, thermal strain, hypoxia, fatigue, head impact, chemical or radiation exposures, metabolic challenges). This effort must also explore the neuropsychological methods in militarily relevant conditions to extend our understanding of relevant functional domains and how well they correspond to modes of testing. The ultimate objective is unobtrusive real-time mental status monitoring.

Recent evidence suggests that cumulative lead exposure among adults in nonoccupational settings can adversely affect cognitive function. Which cognitive domains are affected has not been explored in detail.We used nonlinear spline regressions and linear repeated-measures analysis to assess the association between scores on a battery of cognitive tests over time and both blood and bone lead concentrations in the Normative Aging Study, a cohort of community-dwelling elderly men. Bone lead was measured from 1991 through 1999 with K-shell x-ray fluorescence. A total of 1089 men with a mean (+/-standard deviation) age of 68.7 (+/-7.4) years with blood lead measurements, 761 of whom also had valid bone lead measurements, completed at least one of a battery of cognitive tests. Approximately 3.5 years later, 69% of the men had at least one repeat test. Cognitive testing was performed from 1993 through 2001.On a cross-sectional basis, there was little association between blood or bone lead and cognitive test scores. Change in performance over time on virtually all tests worsened as bone lead increased, with the most robust effects on performance and reaction time scores on visuospatial/visuomotor tests.Low-level cumulative exposure to lead in nonoccupational settings may adversely affect cognitive function, particularly in the visuospatial/visuomotor domain.

OBJECTIVE: To examine the temporal consistency of self-reported deployment-related traumatic brain injury (TBI) and its association with posttraumatic stress disorder (PTSD) symptom severity. SETTING: In-person interviews at US Army installations (postdeployment); phone interviews (long-term follow-up). PARTICIPANTS: A total of 378 US Army soldiers and veterans deployed to Iraq; 14.3% (n = 54) reported TBI with loss of consciousness during an index deployment. DESIGN: Participants were evaluated after returning from deployment and again 5 to 9 years later. MAIN MEASURES: Temporal consistency of TBI endorsement based on TBI screening interviews; PTSD Checklist, Civilian Version. RESULTS: The concordance of deployment-related TBI endorsement from the postdeployment to long-term follow-up assessment was moderate (κ = 0.53). Of the 54 participants reporting (predominantly mild) TBI occurring during an index deployment, 32 endorsed TBI inconsistently over time. More severe PTSD symptoms at postdeployment assessment were independently associated with discordant reporting (P =.0004); each 10-point increase in PCL scores increasing odds of discordance by 69% (odds ratio = 1.69; 95% confidence interval, 1.26-2.26). CONCLUSIONS: Deployment-related TBI may not be reported reliably over time, particularly among war-zone veterans with greater PTSD symptoms. RESULTS of screening evaluations for TBI history should be viewed with caution in the context of PTSD symptom history. Language: en

This study examined the neurocognitive performance of U.S. military personnel completing the Automated Neuropsychological Assessment Metrics (version 4) TBI Military (ANAM4 TBI-MIL) battery as part of the Department of Defense Neurocognitive Functional Assessment Program. Descriptive analyses utilizing the ANAM4TBI Military Performance Database were performed. We examined ANAM Composite Score (ACS) differences between five injury subgroups (no injury, brain injury with current symptoms, brain injury without current symptoms, nonbrain injury with current symptoms, and nonbrain injury without current symptoms) using general linear mixed modeling. Almost 11% (70,472/641,285) reported brain injury in the 4 years before assessment. The ACS differed significantly by injury group (p0.0001). In comparison to the no injury group, those reporting brain injury with current symptoms (d = -0.44) and nonbrain injury with current symptoms (d = -0.24) demonstrated significantly reduced ACS scores (p0.0001) indicative of reduced neurocognitive proficiency. In this population-based study of U.S. military personnel, neurocognitive performance was significantly associated with reported injury within the past 4 years among those experiencing current symptoms. Occupational programs focusing on prospective brain health of injured population groups are warranted.

Background During the Gulf War (GW), in early March 1991, a munitions dump at Khamisiyah, Iraq, was destroyed. Later, in 1996, the dump was found to have contained the organophosphate chemical warfare agents, sarin and cyclosarin. Methods Data collected in a study conducted between 1994 and 1996, before the Khamisiyah incident was publicly disclosed, were used to examine neurobehavioral task performances of GW veterans ( n = 140) categorized as having received high, moderate, or low-to-no exposure dose levels to sarin and cyclosarin at Khamisiyah, Iraq. Exposure levels were based on modeled estimates of the exposure plume and on troop location information at the time of the Khamisiyah event. Based on recent findings observed in follow-up studies of persons exposed to sarin during the 1995 terrorist attacks in Japan, we hypothesized that exposure to sarin and cyclosarin would be associated with poorer performances on objective neurobehavioral tasks in specific functional domains (particularly in visuospatial abilities and psychomotor functioning) in a dose-dependent manner. Results Sarin and cyclosarin exposure was significantly associated with less proficient neurobehavioral functioning on tasks involving fine psychomotor dexterity and visuospatial abilities 4–5 years after exposure. Conclusions Findings suggest a dose–response association between low-level exposure to sarin and cyclosarin and specific functional central nervous system effects 4–5 years after exposure.

This research study examined the prevalence of symptoms and identified risk factors for reported symptoms among a group of Army Gulf War (GW) veterans. A survey was mailed to all members of the Ft. Devens cohort in 1997, representing the third assessment of a group that consisted of 2949 US Army soldiers deployed to the Gulf, and was studied initially in 1991. A total of 1290 subjects responded to the mailed survey; aggressive follow-up methods to address non-response bias were employed. Subjects were classified as having multisymptom illness if they reported symptoms from at least two of three symptom categories (fatigue, mood-cognition, musculoskeletal). Sixty percent of the respondents met criteria for multisymptom illness. Female gender, lower levels of education, psychological symptoms, self-reported use of a medical clinic in the Gulf, ingestion of anti-nerve gas pills (pyridostigmine bromide), anthrax vaccination, tent heaters, exposure to oil fire smoke, and chemical odors were significantly related to multisymptom illness in logistic regression analyses. Analyses in which subjects were stratified by level of psychological symptoms revealed different sets of GW-service environmental exposures and suggest that subgroups of GW veterans may have different sets of risk factors.

Military deployment may adversely affect not only returning veterans, but their families, as well. As a result, researchers have increasingly focused on identifying risk and protective factors for successful family adaptation to war-zone deployment, re-integration of the returning veteran, and the longer-term psychosocial consequences of deployment experienced by some veterans and families. Posttraumatic stress disorder (PTSD) among returning veterans may pose particular challenges to military and military veteran families; however, questions remain regarding the impact of the course of veteran PTSD and other potential moderating factors on family adaptation to military deployment. The Family Foundations Study builds upon an established longitudinal cohort of Army soldiers (i.e., the Neurocognition Deployment Health Study) to help address remaining knowledge gaps. This report describes the conceptual framework and key gaps in knowledge that guided the study design, methodological challenges and special considerations in conducting military family research, and how these gaps, challenges, and special considerations are addressed by the study.

Identifying characteristics that influence smoking behavior among military personnel is critical to protect health and operational functioning.This study prospectively examined rates of cigarette smoking and predictors of changes in smoking behavior as a function of Iraq deployment.One thousand eighty-two US Army soldiers (n = 773 Iraq-deployed; n = 309 nondeployed) completed assessments at two sessions [time 1: April 2003-July 2004; time 2: May 2004-July 2004 (nondeployers); January 2005-September 2006 (deployers)].Approximately 48 % of participants smoked at both time points, with 6 % initiating smoking and 6 % quitting. Smoking initiation was associated with warzone stress exposure; female gender and high military unit support predicted cessation. Military rank and alcohol use were associated with both smoking initiation and cessation.Findings highlight the potential benefits of targeting risk factors for cigarette smoking in comprehensive military health programs aimed at smoking prevention and cessation.

In a large sample of Gulf War veterans (N = 2301) we examined the relations between PTSD symptoms assessed immediately upon returning from the Gulf War and self-reported health problems assessed 18-24 months later. PTSD symptomatology was predictive of self-reported health problems over time for both men and women veterans, even after the effects of combat exposure were removed from the analysis. Female veterans reported significantly more health problems than male veterans, however, there was no interactive effect of gender and PTSD on health problems. These findings provide further support for the theory that psychological response to stressors impacts health outcome.

We describe the clinical evaluation of the nervous-system effects of solvent exposure. We review the current evidence in the epidemiological literature on neurotoxicological effects of solvents, and outline methods and issues to be taken into account in assessment of the patient whose symptoms may be related to solvent toxicity. Primary prevention of these disorders is essential, because treatment options are limited.

Research suggests that military unit support and community postdeployment social support are associated with fewer PTSD symptoms following military deployment. This study extended prior research by examining the associations among predeployment unit support and PTSD symptoms before Iraq deployment as well as unit support, PTSD symptoms, and postdeployment social support after deployment among 835 U.S. Army and 173 National Guard soldiers. Multiple regression analyses indicated that predeployment unit support was not significantly associated with postdeployment PTSD severity in either group of soldiers, whereas higher unit support during deployment was significantly associated with lower postdeployment PTSD severity among active duty soldiers only. Among both groups, higher levels of postdeployment social support were associated with lower levels of postdeployment PTSD symptom severity. These findings suggest that postdeployment social support is a particularly strong buffer against postdeployment PTSD symptoms among both groups of soldiers whereas the effects of unit support may be limited.

Previous research indicates a relationship between perceived fear for one's safety (i.e., threat appraisal) and posttraumatic stress disorder (PTSD). This prospective study examined relationships among deployment- and predeployment-related variables, threat appraisal, and postdeployment PTSD symptom severity. Prior to Iraq deployment, 774 U.S. Army soldiers completed self-report measures assessing previous life stressors, deployment history, current (predeployment) PTSD symptoms, deployment preparedness, and unit cohesion. Following deployment, participants completed self-report measures assessing combat intensity, deployment threat appraisal, and current (postdeployment) PTSD symptoms. Structural equation modeling revealed that predeployment PTSD symptom severity, prior warzone deployment, unit cohesion, and preparedness were each independently associated with deployment threat appraisal, even after taking into account combat intensity. Deployment threat appraisal was associated with postdeployment PTSD severity. Results indicated that predeployment PTSD symptom severity, history of warzone deployment, and preparedness-risk factors previously thought to influence PTSD outcomes directly-were either partially or fully mediated by threat appraisal. The model explained 15% of the variance in deployment threat appraisal and 50% of the variance in postdeployment PTSD severity. Helping service members cope with exposure to extreme stress during deployment by modifying certain prewar risk factors may facilitate reduction of PTSD symptoms following deployment.

To determine whether short-term jet propulsion fuel 8 (JP-8) exposure is associated with balance measurements in JP-8-exposed air force personnel.As part of a larger neuroepidemiology study, balance tasks were completed by JP-8-exposed individuals (n = 37). Short-term JP-8 exposure was measured using personal breathing zone levels and urinary biomarkers. Multivariate linear regression analyses were conducted to examine the relationship between workday JP-8 exposure and postural sway.Balance control decreased as the task became more challenging. Workday exposure to JP-8, measured by either personal air or urinary metabolite levels, was not significantly related to postural sway. Increases in workday postural sway were associated with demographic variables, including younger age, being a current smoker, and higher body mass index.Results suggest that short-term workday JP-8 exposure does not significantly contribute to diminished balance control.

Objective This study aimed to describe methodological challenges encountered in designing a follow-up assessment of US Army Soldiers who served in Operation Iraqi Freedom. Study Design and Setting The Neurocognition Deployment Health Study (NDHS) enrolled 1595 soldiers at 2 military installations, starting in 2003. Prior work compared predeployment and postdeployment assessments among Iraq-deployed and nondeployed soldiers. The current phase, as VA Cooperative Studies Program #566, is collecting follow-up data on participants who were deployed to Iraq or Afghanistan. Specific aims include evaluating the prevalence and course of posttraumatic stress disorder (PTSD), the persistence of previously observed neuropsychological changes, and the relationship of these changes—and traumatic brain injury—to subsequent PTSD. The target sample size is 817 participants, with 200 participants also receiving performance-based neuropsychological assessments. Results We describe 6 methodological challenges and their implications for longitudinal research among a “closed,” young, mobile study population: transitioning from cluster-based (battalion) sampling to individual-level sampling; overcoming practical barriers (such as location searches); selecting exposure and outcome measures that combine previously collected and current study data; accounting for loss of an exposed (deployed) versus (nonexposed) nondeployed comparison; determining timing of assessments; and developing a complex statistical analysis plan. Enrollment is ongoing. Conclusions The study provides unique insights regarding elements of study design and analysis that are relevant to longitudinal research. In particular, the dynamic “real-life” context of military deployment provides a basis for applying observational methodology to characterize mental health disorders associated with exposure to war-zone deployment and other contexts associated with exposure to extreme stress.

BackgroundTraumatic brain injury (TBI) is a concern of contemporary military deployments. Whether milder TBI leads to enduring impairment remains controversial.AimsTo determine the influence of deployment TBI, and posttraumatic stress disorder (PTSD) and depression symptoms on neuropsychological and functional outcomes.MethodA sample of 760 US Army soldiers were assessed pre- and post-deployment. Outcomes included neuropsychological performances and subjective functional impairment.ResultsIn total, 9% of the participants reported (predominantly mild) TBI with loss of consciousness between pre- and post-deployment. At post-deployment, 17.6% of individuals with TBI screened positive for PTSD and 31.3% screened positive for depression. Before and after adjustment for psychiatric symptoms, TBI was significantly associated only with functional impairment. Both PTSD and depression symptoms adjusted for TBI were significantly associated with several neuropsychological performance deficits and functional impairment.ConclusionsMilder TBI reported by deployed service members typically has limited lasting neuropsychological consequences; PTSD and depression are associated with more enduring cognitive compromise.

BACKGROUND Jet propulsion fuel-8 (JP-8) is the primary jet fuel used by the US military, collectively consuming ~2.5 billion gallons annually. Previous reports suggest that JP-8 is potentially toxic to the immune, respiratory, and nervous systems. The objectives of this study were to evaluate inhalation exposure to JP-8 constituents among active duty United States Air Force (USAF) personnel while performing job-related tasks, identify significant predictors of inhalation exposure to JP-8, and evaluate the extent to which surrogate exposure classifications were predictive of measured JP-8 exposures. METHODS Seventy-three full-time USAF personnel from three different air force bases were monitored during four consecutive workdays where personal air samples were collected and analyzed for benzene, ethylbenzene, toluene, xylenes, total hydrocarbons (THC), and naphthalene. The participants were categorized a priori into high- and low-exposure groups, based on their exposure to JP-8 during their typical workday. Additional JP-8 exposure categories included job title groups and self-reported exposure to JP-8. Linear mixed-effects models were used to evaluate predictors of personal air concentrations. RESULTS The concentrations of THC in air were significantly different between a priori exposure groups (2.6 mg m(-3) in high group versus 0.5 mg m(-3) in low, P < 0.0001), with similar differences observed for other analytes in air. Naphthalene was strongly correlated with THC (r = 0.82, P < 0.0001) and both were positively correlated with the relative humidity of the work environment. Exposures to THC and naphthalene varied significantly by job categories based on USAF specialty codes and were highest among personnel working in fuel distribution/maintenance, though self-reported exposure to JP-8 was an even stronger predictor of measured exposure in models that explained 72% (THC) and 67% (naphthalene) of between-worker variability. In fact, both self-report JP-8 exposure and a priori exposure groups explained more between-worker variability than job categories. CONCLUSIONS Personal exposure to JP-8 varied by job and was positively associated with the relative humidity. However, self-reported exposure to JP-8 was an even stronger predictor of measured exposure than job title categories, suggesting that self-reported JP-8 exposure is a valid surrogate metric of exposure when personal air measurements are not available.

There is a potential for widespread occupational exposure to jet fuel among military and civilian personnel. Urinary metabolites of naphthalene have been suggested for use as short-term biomarkers of exposure to jet fuel (jet propulsion fuel 8 (JP8)). In this study, urinary biomarkers of JP8 were evaluated among US Air Force personnel. Personnel (n=24) were divided a priori into high, moderate, and low exposure groups. Pre- and post-shift urine samples were collected from each worker over three workdays and analyzed for metabolites of naphthalene (1- and 2-naphthol). Questionnaires and breathing-zone naphthalene samples were collected from each worker during the same workdays. Linear mixed-effects models were used to evaluate the exposure data. Post-shift levels of 1- and 2-naphthol varied significantly by a priori exposure group (levels in high group>moderate group>low group), and breathing-zone naphthalene was a significant predictor of post-shift levels of 1- and 2-naphthol, indicating that for every unit increase in breathing-zone naphthalene, there was an increase in naphthol levels. These results indicate that post-shift levels of urinary 1- and 2-naphthol reflect JP8 exposure during the work-shift and may be useful surrogates of JP8 exposure. Among the high exposed workers, significant job-related predictors of post-shift levels of 1- and 2-naphthol included entering the fuel tank, repairing leaks, direct skin contact with JP8, and not wearing gloves during the work-shift. The job-related predictors of 1- and 2-naphthol emphasize the importance of reducing inhalation and dermal exposure through the use of personal protective equipment while working in an environment with JP8.

One of the most prevalent workplace chemical exposures historically and currently confronting the global military and civilian workforce is jet propellant (JP) fuel (e.g., JP4, JP5, JP8, jet A1), a complex mixture of numerous hydrocarbon compounds and additives. To date, numerous protective and preventive strategies (e.g., federal exposure limits, workplace procedure protocols, protective gear such as goggles, respirator use, gloves, and coveralls) have been put in place to minimize acutely toxic exposure levels. However, questions remain regarding the effect of repeated exposures at lower (than regulated) levels of JP fuel. The Occupational JP8 Exposure Neuroepidemiology Study (OJENES) was designed to examine the relationships between occupational JP8 exposure over multiple, repeated workdays and specific aspects of central nervous system (CNS) functioning among Air Force (AF) personnel. In this report, we present the OJENES methodology, descriptive findings related to participant characteristics, JP8 exposure levels observed over a work week among higher and lower exposure groups, and neuropsychological task performances at the first study assessment. Results indicated minimal differences between participants in the high and lower exposure groups in terms of descriptive characteristics, other than daily JP8 exposure levels (p

As part of an epidemiologic study of neuropsychological and renal effects of occupational exposure to organic solvents, estimates of cumulative exposure to naphtha were derived for workers at an automobile fuel-injector manufacturing plant. The approach to exposure estimation was relatively unusual in three respects: (1) a marked association between indoor naphtha air concentration and outdoor temperature was modeled and applied to detailed historical temperature data to calculate cumulative exposure estimates; (2) the large number of investigator-generated air samples allowed the use of analyses of variance to compare alternative job-grouping schemes; and (3) the young age of the plant and few process changes allowed for historical exposure estimates with a high degree of confidence. The derived estimates of cumulative exposure appear to offer a firm basis for epidemiologic analyses of exposure-health outcome relationships.

Complaints of neuropsychological dysfunction have emerged among subsets of military personnel after almost every major deployment involving western nations in recent history. Although deployments have been characterized by a range of neural risk factors, psychological stress is common to most prolonged deployments. This review uses a public health framework to address associations between deployment-related stress and neuropsychological performance. Specifically, the review covers mechanisms by which deployment-related psychological stress may affect neuropsychological functioning, considers the advantages and disadvantages of approaching the question from a public health perspective, and discusses how epidemiological research may sort out questions regarding course, cause, and effect. (JINS, 2011, 17, 000–000)

As jet fuel is a common occupational exposure among military and civilian populations, this study was conducted to characterize jet fuel (JP8) exposure among active duty U.S. Air Force personnel. Personnel (n = 24) were divided a priori into high, moderate, and low exposure groups. Questionnaires and personal air samples (breathing zone) were collected from each worker over 3 consecutive days (72 worker-days) and analyzed for total hydrocarbons (THC), benzene, toluene, ethylbenzene, xylenes, and naphthalene. Air samples were collected from inside the fuel tank and analyzed for the same analytes. Linear mixed-effects models were used to evaluate the exposure data. Our results show that the correlation of THC (a measure of overall JP8 inhalation exposure) with all other analytes was moderate to strong in the a priori high and moderate exposure groups combined. Inhalation exposure to all analytes varied significantly by self-reported JP8 exposure (THC levels higher among workers reporting JP8 exposure), a priori exposure group (THC levels in high groupmoderate grouplow group), and more specific job task groupings (THC levels among workers in fuel systems hangar grouprefueling maintenance groupfuel systems office groupfuel handling groupclinic group), with task groupings explaining the most between-worker variability. Among highly exposed workers, statistically significant job task-related predictors of inhalation exposure to THC indicated that increased time in the hangar, working close to the fuel tank (insideless than 25 ftgreater than 25 ft), primary job (entrantattendant/runner/fireguardoutside hangar), and performing various tasks near the fuel tank, such as searching for a leak, resulted in higher JP8 exposure. This study shows that while a priori exposure groups were useful in distinguishing JP8 exposure levels, job task-based categories should be considered in epidemiologic study designs to improve exposure classification. Finally, the strong correlation of THC with naphthalene suggests that naphthalene may be an appropriate surrogate of JP8 exposure. [Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a pdf file containing a table detailing concentrations of JP8 components.].

This prospective study examined: (a) the effects of Iraq War deployment versus non-deployment on pre- to postdeployment change in PTSD symptoms and (b) among deployed soldiers, associations of deployment/postdeployment stress exposures and baseline PTSD symptoms with PTSD symptom change. Seven hundred seventy-four U.S. Army soldiers completed self-report measures of stress exposure and PTSD symptom severity before and after Iraq deployment and were compared with 309 soldiers who did not deploy. Deployed soldiers, compared with non-deployed soldiers, reported increased PTSD symptom severity from Time 1 to Time 2. After controlling for baseline symptoms, deployment-related stressors contributed to longitudinal increases in PTSD symptoms. Combat severity was more strongly associated with symptom increases among active duty soldiers with higher baseline PTSD symptoms.