Performance of Impulse Oscillometry in Identifying Restrictive Lung Defects in a Veteran Cohort.

Background: Impulse oscillometry (IOs) is a technique used to evaluate lung function that uses sound waves imposed over tidal breathing to characterize the airways and lung parenchyma. IOs has been particularly useful in the identification of obstructive lung defects. The present analysis seeks to explore the use of IOs in the identification of restrictive lung physiology among a group of Gulf War I veterans exposed to depleted uranium (DU). Methods: A total of 36 out of a dynamic 85-veteran cohort attended in-person surveillance visits in 2019 and completed both IOs and PFTs. Performance on IOs was evaluated in a cross-sectional analysis of the group overall and in those identified as having restrictive lung defects defined by either spirometry (FEV1/FVC ≥ LLN and FVC < LLN) or lung volumes (TLC < LLN). Results: A total of 6 individuals were identified as having restriction (4 based on spirometry alone and an additional 2 by lung volumes). When restriction was present, IOs values of both resistance and reactance were significantly more abnormal. Conclusion: In the assessment of lung function, IOs may be advantageous over PFTs because it is faster to perform and effort-independent. Although little is known about the utility of IOs in identifying restrictive lung physiology, our results support its use.

Occupational Health Providers' Perceptions of Employee Vaccine Hesitancy.

OBJECTIVE: This study examined the perspectives of occupational health providers (OHPs) on the most frequently encountered clinically relevant reasons for employee vaccine hesitancy. METHODS: We conducted an anonymous, online, cross-sectional survey of US OHPs ( N = 217). The survey asked OHPs about the major reasons that employees cite for being unwilling to receive the following three categories of vaccines: COVID-19, annual influenza, and others relevant to the workplace. RESULTS: Concern about adverse effects was the most frequently reported reason for employee vaccine hesitancy for each vaccine category. Mistrust was reported more frequently for COVID-19 than for the influenza vaccine or other vaccines (χ 2P < 0.05). Targets of employee mistrust included government and researchers or scientists, but mistrust of healthcare providers was uncommon. CONCLUSIONS: These results can be used to inform interventions to address vaccine hesitancy in the occupational health setting.

The Department of Veterans' Affairs Depleted Uranium Cohort in the Time of COVID-19: Translating a Traditional Surveillance Protocol to a Telehealth Platform.

OBJECTIVE: In 2021, 37 members of a cohort of depleted uranium-exposed Gulf War I veterans were evaluated using a protocol tailored to accommodate COVID-19 safety practices on a telehealth platform. METHODS: Individual elements of the legacy protocol were reviewed for urgency and feasibility of inclusion in a modified, telehealth platform. RESULTS: The redesigned protocol included a participant readiness for telehealth assessment, nurse and physician telehealth visits, collection of usual health questionnaires, and urine collections for exposure monitoring for uranium and other fragment-related metal measures. CONCLUSIONS: Despite some limitations in scope, the telehealth platform permitted a visual "visit" with surveillance participants who expressed a high comfort level with the format. The telehealth platform has apparent utility for occupational surveillance and should be explored as a standard approach for surveillance outside of public health emergencies.

Surveillance of Depleted Uranium-exposed Gulf War Veterans: More Evidence for Bone Effects.

ABSTRACT: Gulf War I veterans who were victims of depleted uranium (DU) "friendly-fire" incidents have undergone longitudinal health surveillance since 1994. During the spring of 2019, 36 members of the cohort were evaluated with a monitoring protocol including exposure assessment for total and isotopic uranium concentrations in urine and a comprehensive review of health outcomes, including measures of bone metabolism and bone mineral density (BMD) determination. Elevated urine U concentrations were observed in cohort members with retained depleted uranium (DU) shrapnel fragments. In addition, a measure of bone resorption, N-telopeptide, showed a statistically significant increase in those in the high DU subgroup, a finding consistent with a statistically significant decrease in bone mass also observed in this high DU subgroup compared to the low DU subgroup. After more than 25 y since first exposure to DU, an aging cohort of military veterans continues to show few U-related health effects in known target organs of U toxicity. The new finding of impaired BMD in the high DU subgroup has now been detected in two consecutive surveillance visits. While this is a biologically plausible uranium effect, it is not reflected in other measures of bone metabolism in the full cohort, which have largely been within normal limits. However, ongoing accrual of the U burden from fragment absorption over time and the effect of aging further impairing BMD suggest the need for future surveillance assessments of this cohort.

Cleaning and Disinfection Perceptions and Use Practices Among Elastomeric Respirator Users in Health care.

BACKGROUND: Reusable elastomeric respirator use in health care may represent one solution to address N95 respirator shortages experienced during infectious disease outbreaks, but cleaning and disinfection requirements may limit their utility. Evidence of respirator cleaning and disinfection behaviors and practices by health care workers may inform guidance on reusable respirator use. METHODS: Medical system elastomeric respirator users were surveyed about respirator cleaning and disinfection practices and perceptions via an electronic survey. Respondents were subsequently classified based on reported compliance with their assigned respirator use. To explore whether respirator cleaning and disinfection issues affected compliance with assigned device use, responses were compared between user groups and adjusted for covariates. RESULTS: A total of 432 of 2,024 (21%) eligible elastomeric respirator users completed the survey. Most (>90%) reported that their respirator was clean, but only 52% reported that they always disinfect their respirators after use according to the hospital's expected practice. Only 40 respondents (9%) reported regularly cleaning the respirator with soap and water, in accordance with manufacturer recommendations. Reporting of suboptimal decontamination practice was not associated with assigned device compliance, however, except among providers and respiratory therapists. CONCLUSION/APPLICATION TO PRACTICE: Although perceptions of cleanliness and adherence to expected decontamination practices during routine use did not appear to influence compliance with assigned respirator use overall, this did predict compliance among providers and respiratory therapists, both of whom have nonfixed workstations. Practical and effective strategies to assure easy access to and availability of clean reusable respiratory protective devices are needed to facilitate their use in health care respiratory protection programs.

Self-reported impact of respirator use on health care worker ability to perform patient care.

In a study of 1,152 health care workers surveyed prior to the COVID-19 pandemic, most disagreed that respiratory protective equipment use interferes with patient care but reported that it would affect respirator use compliance if it did. A patient's fear reaction variably influenced self-reported health care worker compliance with respirator use. Strategies to improve protective equipment design may remove potential barriers to respirator use and allow better health care worker-patient relationships.

Storage and Availability of Elastomeric Respirators in Health Care.

Use of reusable respirators, such as elastomeric half-face respirators (EHFRs), may serve as one solution to combating the problem of N95 respirator shortages experienced during infectious disease emergencies. To clarify whether logistical issues like respirator storage and availability are barriers to implementation of healthcare respiratory protection strategies that include EHFRs, this study aimed to evaluate the availability, storage, and respirator and filter replacement practices of EHFRs used in healthcare settings under routine use. Healthcare workers using EHFRs were surveyed about their use practices. To explore whether issues related to storage and availability of EHFRs affected compliance with assigned respirator use, responses were compared between concordant users and EHFR users who were assigned to use EHFRs but currently use different respirators ("discordant users"). Most concordant EHFR users reported that their respirator was always available when needed (63.8%). Almost two-thirds of concordant but only half of discordant users reported storing their EHFRs conveniently in the patient care area (p = <0.001). Among mobile workers, discordant users had higher odds (aOR = 3.2, 95% CI [1.4,7.5]) of reporting that their respirator was not stored in the patient care area, suggesting that storage location has a significant impact on compliance with expected practice, particularly in this group. Storage and access are barriers to optimal elastomeric respirator use in healthcare. Strategies to assure ready availability and storage of respirators will permit EHFR inclusion in pandemic and routine respiratory protection programs.

User acceptance of reusable respirators in health care.

BACKGROUND: Inclusion of reusable respirators, such as elastomeric half-face respirators (EHFRs) and powered air-purifying respirators (PAPRs), in hospital respiratory protection inventories may represent 1 solution to the problem of N95 respirator shortages experienced during pandemics. User acceptance of these devices is 1 potential barrier to implementing such a strategy in respiratory protection programs. METHODS: To assess user attitudes toward various respirators, health care workers enrolled in respiratory protection programs in a medical system using EHFRs, N95s, and PAPRs and completed an online questionnaire that addressed attitudes, beliefs, and respirator preferences under different risk scenarios. Responses were compared between user groups. RESULTS: Of 1,152 participants, 53% currently used N95s, 24% used EHFRs, and 23% used PAPRs. N95 users rated their respirators more favorably compared with EHFR and PAPR users (P < .001) regarding comfort and communication, however, EHFR users rated their respirators much more highly regarding sense of protection (P < .001). For all user groups, reusable respirators were significantly more likely (odds ratios 2.3-7.7) to be preferred over N95 filtering facepiece respirators in higher risk scenarios compared to "usual circumstance" scenarios. CONCLUSIONS: Despite somewhat less favorable ratings on comfort and communication, experienced EHFR and PAPR users still prefer reusable respirators over N95s in certain higher risk scenarios. This suggests that reusable respirators are an acceptable alternative to N95 respirators in health care and offer 1 viable solution to prevent pandemic-generated respirator shortages.

Semen Uranium Concentrations in Depleted Uranium Exposed Gulf War Veterans: Correlations with Other Body Fluid Matrices.

Environmental metal exposure, as well as dietary metals, may adversely affect semen quality even as others play an essential role in normal spermatogenesis and fertility. Measures of seminal fluid metals have therefore been of high interest in the last several decades but have shown inconsistent results in correlations with some semen quality parameters. As well, environmental metal measures across various body fluid matrices have not been consistently correlated contrary to what one might hypothesize based on a systemic body burden of metal. This may be due to the body fluid matrices assessed and to other differences in laboratory methods and sample preparation. Measures of uranium, a potentially toxic metal in humans, have not previously been reported in the semen of environmentally metal-exposed populations. We report here uranium seminal fluid results and the high correlation of uranium concentrations across several body fluid matrices in a cohort of military veterans exposed to depleted uranium in combat events during the Iraqi Gulf War. These results inform the risk communication conversation for exposed populations and broaden the public health assessments from various exposure scenarios.

Surveillance results and bone effects in the Gulf War depleted uranium-exposed cohort.

A small group of Gulf War I veterans wounded in depleted uranium (DU) friendly-fire incidents have been monitored in a clinical surveillance program since 1993. During the spring of 2017, 42 members of the cohort were evaluated with a protocol which includes exposure monitoring for total and isotopic uranium concentrations in urine and a comprehensive assessment of health outcomes including measures of bone metabolism, and for participants >50 years, bone mineral density (BMD) determination. Elevated urine U concentrations were observed in cohort members with retained DU shrapnel fragments. Only the mean serum estradiol concentration, a marker of bone metabolism, was found to be significantly different for lower-vs- higher urine U (uU) cohort sub-groups. For the first time, a significant deficit in BMD was observed in the over age 50, high uU sub-group. After more than 25 years since first exposure to DU, an aging cohort of military veterans continues to exhibit few U-related adverse health effects in known target organs of U toxicity. The new finding of reduced BMD in older cohort members, while biologically plausible, was not suggested by other measures of bone metabolism in the full (all ages) cohort, as these were predominantly within normal limits over time. Only estradiol was recently found to display a difference as a function of uU grouping. As BMD is further impacted by aging and the U-burden from fragment absorption accrues in this cohort, a U effect may be clarified in future surveillance visits.

Impulse oscillometry measurement of distal airways obstruction in depleted uranium-exposed Gulf War veterans.

INTRODUCTION: A cohort of Gulf War I veterans who sustained exposure to depleted uranium undergoes biennial surveillance for potential uranium-related health effects. We performed impulse oscillometry and hypothesized that veterans with higher uranium body burdens would have more obstructive abnormalities than those with lower burdens. METHODS: We compared pulmonary function of veterans in high versus low urine uranium groups by evaluating spirometry and oscillometry values. RESULTS: Overall mean spirometry and oscillometry resistance values fell within the normal ranges. There were no significant differences between the high and low uranium groups for any parameters. However, more veterans were classified as having obstruction by oscillometry (42%) than spirometry (8%). CONCLUSIONS: While oscillometry identified more veterans as obstructed, obstruction was not uranium-related. However, the added sensitivity of this method implies a benefit in wider surveillance of exposed cohorts and holds promise in identifying abnormalities in areas of the lung historically described as silent.

The U.S. Department of Veterans' Affairs depleted uranium exposed cohort at 25 Years: Longitudinal surveillance results.

BACKGROUND: A small group of Gulf War I veterans wounded in depleted uranium (DU) friendly-fire incidents have been monitored for health changes in a clinical surveillance program at the Veterans Affairs Medical Center, Baltimore since 1994. METHODS: During the spring of 2015, an in-patient clinical surveillance protocol was performed on 36 members of the cohort, including exposure monitoring for total and isotopic uranium concentrations in urine and a comprehensive assessment of health outcomes. RESULTS: On-going mobilization of U from embedded fragments is evidenced by elevated urine U concentrations. The DU isotopic signature is observed principally in participants possessing embedded fragments. Those with only an inhalation exposure have lower urine U concentration and a natural isotopic signature. CONCLUSIONS: At 25 years since first exposure to DU, an aging cohort of military veterans continues to show no U-related health effects in known target organs of U toxicity. As U body burden continues to accrue from in-situ mobilization from metal fragment depots, and increases with exposure duration, critical tissue-specific U concentration thresholds may be reached, thus recommending on-going surveillance of this veteran cohort.

Qualitative Analysis of Origins and Evolution of an Elastomeric Respirator-based Hospital Respiratory Protection Program.

Elastomeric respirators (elastomerics) may serve as one alternative to disposable N95 respirator use in healthcare. We explored factors which drove elastomeric adoption and continued use in a large academic medical center. We conducted semi-structured and focus group interviews in 2015 with a) 11 leadership key informants (KIs) with involvement in the respiratory protection program (RPP) when elastomerics were introduced and b) 11 healthcare workers (HCWs) recruited from hospital departments assigned to use elastomerics. Interview transcripts and responses were open-coded to capture emergent themes, which were collapsed into broader categories and iteratively refined. Factors identified by leadership KIs as influencing elastomeric adoption included: 1) N95 shortages during 2009's H1N1 influenza pandemic and 2) the presence of trained, certified safety professionals who were familiar with respiratory protection requirements. Factors identified as influencing ongoing use of elastomerics included: 1) cleaning/decontamination practices, 2) storage, 3) safety culture, 4) HCW respirator knowledge, and 5) risk perception. HCW users expressed dissatisfaction related to breathing, communication and cleaning of elastomerics. Other themes included convenience use of N95s rather than assigned elastomerics, despite perceptions that elastomerics are more protective. Through semi-structured and focus group interviews, we learned that 1) leadership introduced elastomerics due to necessity but now face challenges related to ongoing use, and 2) HCWs were not satisfied with elastomerics for routine care and preferentially used N95s because they were conveniently available at point of use. Although the impetus behind incorporation of elastomerics was clear, the most complex themes related to sustainability of this form of RPP. These themes were used to inform a broader questionnaire and will address the utility of elastomerics as a feasible and acceptable practical alternative to N95s in healthcare.

Significance of dermatologic findings in a cohort of depleted uranium-exposed veterans of Iraqi conflicts.

BACKGROUND: Depleted uranium (DU)-containing weapons have been used in military operations since 1991. There is interest in following veterans who were occupationally exposed to DU by either inhalation or retention of fragments. A cohort of DU-exposed Gulf War I veterans has been followed longitudinally at the Baltimore Veterans Administration Medical Center since 1993. OBJECTIVE: The aim was to monitor chronic dermatological findings associated with occupational DU exposure in the 2013 cohort. METHODS: Thirty-five veterans were evaluated. This study was reviewed and approved by the institutional review board and the Baltimore Veterans Administration Medical Center research service. Depleted uranium exposure was measured using creatinine-adjusted urine uranium concentrations (micrograms of uranium per gram of creatinine [µgU/gCrea]). Detailed medical histories, physical examinations, and exposure histories were performed. RESULTS: Using a cutoff level of 0.1 µgU/gCrea, 11 veterans were placed in the high-uranium exposure group, whereas 23 veterans were placed in the low-uranium exposure group. Retained fragments were documented in 91% of the high-exposure group versus that in 13% of the low-exposure group (P < 0.001), and fragment-related scarring was significantly increased in the high-exposure group (P = 0.002). Other dermatological findings such as dermatitis were also assessed. CONCLUSIONS: Fragment retainment and related scarring was significantly increased in veterans exposed to high levels of DU. Continuous monitoring of this cohort will yield interesting dermatological findings related to DU exposure.

Biologic monitoring and surveillance results for the department of veterans affairs' depleted uranium cohort: Lessons learned from sustained exposure over two decades.

BACKGROUND: A small group of Gulf War I veterans wounded in depleted uranium (DU) friendly fire incidents have been monitored in a clinical surveillance program at the Veterans Affairs Medical Center, Baltimore since 1994. METHODS: An in-patient clinical surveillance protocol was performed on 35 members of the cohort, including exposure monitoring for total and isotopic uranium concentrations in urine and a comprehensive assessment of health outcomes. RESULTS: Although urine U concentrations continue to be elevated in this group, illustrating on-going in situ mobilization of U from embedded fragments, no consistent U-related health effects have been observed. CONCLUSIONS: Now more than 20 years since first exposure to DU, an aging cohort of military veterans continues to show no U-related health effects in known target organs of U toxicity. As tissue concentrations continue to accrue with exposure duration, critical tissue-specific U concentration thresholds may be reached, thus recommending on-going surveillance of this veteran cohort.

Mutagenicity monitoring following battlefield exposures: Longitudinal study of HPRT mutations in Gulf War I veterans exposed to depleted uranium.

A total of 70 military Veterans have been monitored for HPRT T-cell mutations in five separate studies at 2-year intervals over an 8-year period. Systemic depleted uranium (DU) levels were measured at the time of each study by determining urinary uranium (uU) excretion. Each HPRT study included 30-40 Veterans, several with retained DU-containing shrapnel. Forty-nine Veterans were evaluated in multiple studies, including 14 who were in all five studies. This permitted a characterization of the HPRT mutation assay over time to assess the effects of age, smoking and non-selected cloning efficiencies, as well as the inter- and intra-individual variability across time points. Molecular analyses identified the HPRT mutation and T-cell receptor (TCR) gene rearrangement in 1,377 mutant isolates. An unexpected finding was that in vivo clones of HPRT mutant T-cells were present in some Veterans, and could persist over several years of the study. The calculated HPRT mutant frequencies (MFs) were repeatedly elevated in replicate studies in three outlier Veterans with elevated urinary uranium excretion levels. However, these three outlier Veterans also harbored large and persistent in vivo HPRT mutant T-cell clones, each of which was represented by a single founder mutation. Correction for in vivo clonality allowed calculation of HPRT T-cell mutation frequencies (MutFs). Despite earlier reports of DU associated increases in HPRT MFs in some Veterans, the results presented here demonstrate that HPRT mutations are not increased by systemic DU exposure. Additional battlefield exposures were also evaluated for associations with HPRT mutations and none were found.

Mutagenicity monitoring following battlefield exposures: Molecular analysis of HPRT mutations in Gulf War I veterans exposed to depleted uranium.

Molecular studies that involved cDNA and genomic DNA sequencing as well as multiplex PCR of the HPRT gene were performed to determine the molecular mutational spectrum for 1,377 HPRT mutant isolates obtained from 61 Veterans of the 1991 Gulf War, most of whom were exposed to depleted uranium (DU). Mutant colonies were isolated from one to four times from each Veteran (in 2003, 2005, 2007, and/or 2009). The relative frequencies of the various types of mutations (point mutations, deletions, insertions, etc.) were compared between high versus low DU exposed groups, (based on their urine U concentration levels), with HPRT mutant frequency (as determined in the companion paper) and with a database of historic controls. The mutational spectrum includes all classes of gene mutations with no significant differences observed in Veterans related to their DU exposures.

Pulmonary health effects in Gulf War I service members exposed to depleted uranium.

OBJECTIVE: In a population of Gulf War I veterans who sustained inhalational exposure to depleted uranium during friendly fire incidents in 1991, we evaluated whether those with high body burdens of uranium were more likely to have pulmonary health abnormalities than those with low body burdens. METHODS: We compared self-reported respiratory symptoms, mean pulmonary function values, and prevalence of low-dose chest computed tomography abnormalities between high and low urine uranium groups. RESULTS: We found no significant differences in respiratory symptoms, abnormal pulmonary function values, or prevalence of chest computed tomography abnormalities between high and low urine uranium groups. Overall, the cohort's pulmonary function values fell within the expected clinical range. CONCLUSIONS: Our results support previous estimates that the depleted uranium levels inhaled during the 1991 friendly fire incidents likely do not cause long-term adverse pulmonary health effects.

The Gulf War depleted uranium cohort at 20 years: bioassay results and novel approaches to fragment surveillance.

During the 1991 GulfWar, U.S. service members were exposed to depleted uranium (DU) through friendly-fire incidents involving DU munitions and vehicles protected by DU armor. Routes of exposure to DU involved inhalation of soluble and insoluble DU oxide particles, wound contamination, and retained embedded DU metal fragments that continue to oxidize in situ and release DU to the systemic circulation. A biennial health surveillance program established for this group of Veterans by the U.S. Department of Veterans Affairs has shown continuously elevated urine DU concentrations in the subset of veterans with embedded fragments for over 20 years. While the 2011 assessment was comprehensive, few clinically significant U-related health effects were observed. This report is focused on health outcomes associated with two primary target organs of concern for long term effects of this combat-related exposure to DU. Renal biomarkers showed minimal DU-related effects on proximal tubule function and cytotoxicity, but significant biomarker results were observed when urine concentrations of multiple metals also found in fragments were examined together. Pulmonary tests and questionnaire results indicate that pulmonary function after 20 y remains within the clinical normal range. Imaging of DU embedded fragment-associated tissue for signs of inflammatory or proliferative reactions possibly associated with foreign body transformation or with local alpha emissions from DU was also conducted using PET-CT and ultrasound. These imaging tools may be helpful in guiding decisions regarding removal of fragments.