Zinc transporters and their functional integration in mammalian cells

Zinc is a ubiquitous biological metal in all living organisms. The spatiotemporal zinc dynamics in cells provide crucial cellular signaling opportunities, but also challenges for intracellular zinc homeostasis with broad disease implications. Zinc transporters play a central role in regulating cellular zinc balance and subcellular zinc distributions. The discoveries of two complementary families of mammalian zinc transporters (ZnTs and ZIPs) in the mid-1990s spurred much speculation on their metal selectivity and cellular functions. After two decades of research, we have arrived at a biochemical description of zinc transport. However, in vitro functions are fundamentally different from those in living cells, where mammalian zinc transporters are directed to specific subcellular locations, engaged in dedicated macromolecular machineries, and connected with diverse cellular processes. Hence, the molecular functions of individual zinc transporters are reshaped and deeply integrated in cells to promote the utilization of zinc chemistry to perform enzymatic reactions, tune cellular responsiveness to pathophysiologic signals, and safeguard cellular homeostasis. At present, the underlying mechanisms driving the functional integration of mammalian zinc transporters are largely unknown. This knowledge gap has motivated a shift of the research focus from in vitro studies of purified zinc transporters to in cell studies of mammalian zinc transporters in the context of their subcellular locations and protein interactions. In this review, we will outline how knowledge of zinc transporters has been accumulated from in-test-tube to in-cell studies, highlighting new insights and paradigm shifts in our understanding of the molecular and cellular basis of mammalian zinc transporter functions.

Characterization of Limited Duty Neuromusculoskeletal Injuries and Return to Duty Times in the U.S. Army During 2017-2018

INTRODUCTION

Neuromusculoskeletal injuries (MSKI) are the leading cause of medical encounters, lost or limited duty days, medical evacuations, and disability in the U.S. Army. In the U.S. Army, objective MSKI incidence rate metrics can be determined through medical encounter data (M2SKIs) with International Classification of Diseases (ICD) 9 and ICD 10 codes or through documented limited duty profiles (LDPs) documenting time-loss MSKI (TLMSKI). The purpose of the current study was to characterize the population incidence of TLMSKIs among U.S. Army soldiers.

MATERIALS AND METHODS

This study was approved by the Medical Research and Development Command's Institutional Review Board. This was a retrospective population-level study. The U.S. Army's eProfile system was utilized to characterize all LDPs issued during 2017-2018 and to describe the body regions injured and activities associated with these TLMSKIs.

RESULTS

The incidence rate of TLMSKIs was found to be 44 and 40 TLMSKI/100 soldier-years for 2017 and 2018, respectively, which is lower than previously published incidence rates using MSKI receiving medical care. Approximately one quarter of the total active duty Army population in 2017 and 2018 recorded limited duty injuries, where those to the ankle/foot region resulted in the most LDPs and those to the knee resulted in the most lost duty days. The majority of all TLMSKIs were associated with fitness training-related activities.

CONCLUSION

This descriptive study is the first to present the U.S. Army population rates for MSKIs that result in LDPs, representing key time losses when soldiers cannot participate in their military occupational and physical training tasks. This study utilizes the LDP system to calculate limited duty days instead of attempting to estimate this information from other means. The eProfile system is limited in that it combines body regions such as ankle/foot and does not allow isolation of ankle or foot independently. It is recommended that research and training programs target the identification, development, and validation of effective and scaleable strategies to maximize performance without severely reducing combat effectiveness because of training TLMSKIs.

Sleep health of incoming army trainees and how it changes during basic combat training

OBJECTIVE

To examine the sleep health of incoming Army trainees and how it is impacted during basic combat training (BCT).

DESIGN

Prospective.

SETTING

BCT site (Fort Jackson, SC).

PARTICIPANTS

A total of 1349 trainees (936 = male, 413 = female, 20.73 ± 3.67 years).

MEASUREMENTS

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.

RESULTS

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]).

CONCLUSIONS

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.

Effect of Environmental Temperature and Humidity on Permethrin Biomarkers of Exposure in U.S. Soldiers Wearing Permethrin-Treated Uniforms

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.

The ZIP6/ZIP10 heteromer is essential for the zinc-mediated trigger of mitosis

Zinc has been known to be essential for cell division for over 40 years but the molecular pathways involved remain elusive. Cellular zinc import across biological membranes necessitates the help of zinc transporters such as the SLC39A family of ZIP transporters. We have discovered a molecular process that explains why zinc is required for cell division, involving two highly regulated zinc transporters, as a heteromer of ZIP6 and ZIP10, providing the means of cellular zinc entry at a specific time of the cell cycle that initiates a pathway resulting in the onset of mitosis. Crucially, when the zinc influx across this heteromer is blocked by ZIP6 or ZIP10 specific antibodies, there is no evidence of mitosis, confirming the requirement for zinc influx as a trigger of mitosis. The zinc that influxes into cells to trigger mitosis additionally changes the phosphorylation state of STAT3 converting it from a transcription factor to a protein that complexes with this heteromer and pS³⁸Stathmin, the form allowing microtubule rearrangement as required in mitosis. This discovery now explains the specific cellular role of ZIP6 and ZIP10 and how they have special importance in the mitosis process compared to other ZIP transporter family members. This finding offers new therapeutic opportunities for inhibition of cell division in the many proliferative diseases that exist, such as cancer.

Permethrin exposure from wearing fabric-treated military uniforms in high heat conditions under varying wear-time scenarios

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.

Detailed analyses of the crucial functions of Zn transporter proteins in alkaline phosphatase activation

Numerous zinc ectoenzymes are metalated by zinc and activated in the compartments of the early secretory pathway before reaching their destination. Zn transporter (ZNT) proteins located in these compartments are essential for ectoenzyme activation. We have previously reported that ZNT proteins, specifically ZNT5-ZNT6 heterodimers and ZNT7 homodimers, play critical roles in the activation of zinc ectoenzymes, such as alkaline phosphatases (ALPs), by mobilizing cytosolic zinc into these compartments. However, this process remains incompletely understood. Here, using genetically-engineered chicken DT40 cells, we first determined that Zrt/Irt-like protein (ZIP) transporters that are localized to the compartments of the early secretory pathway play only a minor role in the ALP activation process. These transporters included ZIP7, ZIP9, and ZIP13, performing pivotal functions in maintaining cellular homeostasis by effluxing zinc out of the compartments. Next, using purified ALP proteins, we showed that zinc metalation on ALP produced in DT40 cells lacking ZNT5-ZNT6 heterodimers and ZNT7 homodimers is impaired. Finally, by genetically disrupting both ZNT5 and ZNT7 in human HAP1 cells, we directly demonstrated that the tissue-nonspecific ALP-activating functions of both ZNT complexes are conserved in human cells. Furthermore, using mutant HAP1 cells, we uncovered a previously-unrecognized and unique spatial regulation of ZNT5-ZNT6 heterodimer formation, wherein ZNT5 recruits ZNT6 to the Golgi apparatus to form the heterodimeric complex. These findings fill in major gaps in our understanding of the molecular mechanisms underlying zinc ectoenzyme activation in the compartments of the early secretory pathway.

Cognitive Behavioural Therapy for Nightmares for Patients with Persecutory Delusions (Nites): An Assessor-Blind, Pilot Randomized Controlled Trial

OBJECTIVE

Nightmares are relatively common in patients experiencing psychosis but rarely assessed or treated. Nightmares may maintain persecutory delusions by portraying fears in sensory-rich detail. We tested the potential benefits of imagery-focused cognitive behavioural therapy (CBT) for nightmares on nightmare severity and persecutory delusions.

METHOD

This assessor-blind parallel-group pilot trial randomized 24 participants with nightmares and persecutory delusions to receive CBT for nightmares delivered over 4 weeks in addition to treatment as usual (TAU) or TAU alone. Assessments were at 0, 4 (end of treatment), and 8 weeks (follow-up). Feasibility outcomes assessed therapy uptake, techniques used, satisfaction, and attrition. The primary efficacy outcome assessed nightmare severity at week 4. Analyses were intention to treat, estimating treatment effect with 95% confidence intervals (CIs).

RESULTS

All participants offered CBT completed therapy (mean [SD], 4.8 [0.6] sessions) with high satisfaction, and 20 (83%) participants completed all assessments. Compared with TAU, CBT led to large improvements in nightmares (adjusted mean difference = -7.0; 95% CI, -12.6 to -1.3; d = -1.1) and insomnia (6.3; 95% CI, 2.6 to 10.0; d = 1.4) at week 4. Gains were maintained at follow-up. Suicidal ideation was not exacerbated by CBT but remained stable to follow-up, compared with TAU, which reduced at follow-up (6.8; 95% CI, 0.3 to 3.3; d = 0.7). CBT led to reductions in paranoia (-20.8; 95% CI, -43.2 to 1.7; d = -0.6), although CIs were wide. Three serious adverse events were deemed unrelated to participation (CBT = 2, TAU = 1).

CONCLUSIONS

CBT for nightmares is feasible and may be efficacious for treating nightmares and comorbid insomnia for patients with persecutory delusions. It shows promise on paranoia but potentially not on suicidal ideation.

The comments of voices on the appearance of patients with psychosis: 'the voices tell me that I am ugly'

BACKGROUND

There are high rates of obesity and low self-esteem in patients with psychosis. The occurrence of negative voice content directly about appearance is therefore plausible. Derogatory comments about appearance are likely to be distressing, increase depression and contribute to social withdrawal.

AIMS

To systematically assess the occurrence of voice content regarding appearance and identify correlates.

METHOD

Sixty patients experiencing verbal auditory hallucinations at least once a week in the context of non-affective psychosis completed a measure assessing positive and negative voice content about appearance. They also completed assessments about body image, self-esteem, psychiatric symptoms and well-being.

RESULTS

Fifty-five (91.7%) participants reported hearing voices comment on their appearance. A total of 54 (90%) patients reported negative voice content about their appearance with 30 (50%) patients experienced negative appearance comments on a daily basis. The most common negative comment was 'the voices tell me that I am ugly' (n = 48, 80%). There were 39 (65%) patients who reported positive voice content on appearance. The most frequent positive comment was 'I look as nice as other people' (n = 26, 43.3%). Negative voice content about appearance was associated with body image concerns, paranoia, voice hearing severity, depression, worry, negative self-beliefs and safety-seeking behaviours. Positive appearance voice content was associated with greater body esteem and well-being and lower levels of depression and insomnia.

CONCLUSIONS

Voice content about appearance is very common for patients seen in clinical services. Negative voice content may reflect - and subsequently reinforce - negative beliefs about one's appearance, low self-esteem, worry and paranoia.

DECLARATION OF INTEREST

None.

The weeks before 100 persecutory delusions: the presence of many potential contributory causal factors

BACKGROUND

The period before the formation of a persecutory delusion may provide causal insights. Patient accounts are invaluable in informing this understanding.

AIMS

To inform the understanding of delusion formation, we asked patients about the occurrence of potential causal factors - identified from a cognitive model - before delusion onset.

METHOD

A total of 100 patients with persecutory delusions completed a checklist about their subjective experiences in the weeks before belief onset. The checklist included items concerning worry, images, low self-esteem, poor sleep, mood dysregulation, dissociation, manic-type symptoms, aberrant salience, hallucinations, substance use and stressors. Time to reach certainty in the delusion was also assessed.

RESULTS

Most commonly it took patients several months to reach delusion certainty (n = 30), although other patients took a few weeks (n = 24), years (n = 21), knew instantly (n = 17) or took a few days (n = 6). The most frequent experiences occurring before delusion onset were: low self-confidence (n = 84); excessive worry (n = 80); not feeling like normal self (n = 77); difficulties concentrating (n = 77); going over problems again and again (n = 75); being very negative about the self (n = 75); images of bad things happening (n = 75); and sleep problems (n = 75). The average number of experiences occurring was high (mean 23.5, s.d. = 8.7). The experiences clustered into six main types, with patients reporting an average of 5.4 (s.d. = 1.0) different types.

CONCLUSIONS

Patients report numerous different experiences in the period before full persecutory delusion onset that could be contributory causal factors, consistent with a complex multifactorial view of delusion occurrence. This study, however, relied on retrospective self-report and could not determine causality.

DECLARATION OF INTEREST

None.

Treatable clinical intervention targets for patients with schizophrenia

BACKGROUND

Treatment approaches for patients with psychosis need major improvement. Our approach to improvement is twofold: target putative causal mechanisms for psychotic experiences that are treatable and also that patients wish treated. This leads to greater treatment engagement and clinical benefit. To inform mental health service provision we assessed the presence of treatable causal mechanisms and patient treatment preferences.

METHODS

Patients with non-affective psychosis attending NHS mental health services completed assessments of paranoia, hallucinations, anxious avoidance, worry, self-esteem, insomnia, analytic reasoning, psychological well-being, and treatment preferences.

RESULTS

1809 patients participated. Severe paranoia was present in 53.4% and frequent voices in 48.2%. Of the causal mechanisms, severe worry was present in 67.7%, avoidance at agoraphobic levels in 64.5%, analytic reasoning difficulties in 55.9%, insomnia in 50.1%, poor psychological well-being in 44.3%, strongly negative self-beliefs in 36.6%, and weak positive self-beliefs in 19.2%. Treatment target preferences were: feeling happier (63.2%), worrying less (63.1%), increasing self-confidence (62.1%), increasing activities (59.6%), improving decision-making (56.5%), feeling safer (53.0%), sleeping better (52.3%), and coping with voices (45.3%). Patients with current paranoia and/or hallucinations had higher levels of the causal factors and of wanting these difficulties treated.

CONCLUSIONS

Patients with non-affective psychosis have high levels of treatable problems such as agoraphobic avoidance, worry, low self-esteem, and insomnia and they would like these difficulties treated. Successful treatment of these difficulties is also likely to decrease psychotic experiences such as paranoia.

Activated zinc transporter ZIP7 as an indicator of anti-hormone resistance in breast cancer

ZIP7, a member of the ZIP family of zinc importers, resides on the endoplasmic reticulum membrane and transports zinc from intracellular stores to the cytoplasm after activation by CK2 phosphorylation on two serine residues (S275 and S276). ZIP7 is known to be required for the growth of anti-hormone resistant breast cancer models, especially those with acquired tamoxifen resistance developed from MCF-7. Using our new pS275S276ZIP7 antibody which only recognises activated ZIP7 (pZIP7), we have demonstrated that the hyperactivation of ZIP7 is prevalent in tamoxifen-resistant breast cancer cells. This evidence suggests that pZIP7 might have potential as a biomarker of acquired resistance to such anti-hormones in breast cancer, a current unmet clinical need. In this regard, we have also developed a new immunohistochemical assay for pZIP7 which allowed pZIP7 to be tested on a small clinical series of breast cancer tissues confirming its prevalence in such tumours and relationship to a variety of clinicopathological parameters and biomarkers previously associated with endocrine resistant phenotypes, notably increased activated MAPK signalling, expression of ErbB2, CD71 and the proto-oncogene c-Fos, as well as with increased tumour grade.

Suicidal ideation and behaviour in patients with persecutory delusions: Prevalence, symptom associations, and psychological correlates

BACKGROUND

To determine the prevalence of suicidal ideation and behaviour - and their correlates - in patients with persecutory delusions.

METHODS

110 patients with persecutory delusions in the context of non-affective psychosis were assessed for suicidal thoughts and behaviours over the past month. Symptom and psychological assessments were also completed.

RESULTS

The severity of suicidal ideation was: no suicidal ideation (n = 26, 23.6%); wish to be dead (n = 21, 19.1%); nonspecific active suicidal thoughts (n = 14, 12.7%); suicidal thoughts with methods but no intent (n = 29, 26.4%); suicidal thoughts with intent but no specific plan (n = 13, 11.8%); and suicidal intent with plan (n = 7, 6.4%). In the past month, five patients (4.5%) had made an actual, interrupted, or aborted suicide attempt. The severity of suicidal ideation was associated with higher levels of depression, paranoia, hallucinations, anger, insomnia, negative beliefs about the self and others, pessimism, worry, and delusion safety-seeking behaviours and lower levels of psychological well-being and reward responsiveness. Severity of ideation was not associated with cannabis or alcohol use, working memory, pain, or meaningful activity levels.

CONCLUSIONS

Patients with persecutory delusions are typically in a severe state of psychological stress, and at risk of suicide, as indicated by very high levels of suicidal ideation. This exploratory study also identifies correlates of suicidal ideation that could be investigated in causal research designs.

A prospective field study of U.S. Army trainees to identify the physiological bases and key factors influencing musculoskeletal injuries: a study protocol

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.

ZnR/GPR39 upregulation of K+/Cl--cotransporter 3 in tamoxifen resistant breast cancer cells

Expression of the zinc receptor, ZnR/GPR39, is increased in higher grade breast cancer tumors and cells. Zinc, its ligand, is accumulated at larger concentrations in the tumor tissue and can therefore activate ZnR/GPR39-dependent Ca²⁺ signaling leading to tumor progression. The K⁺/Cl^- co-transporters (KCC), activated by intracellular signaling, enhance breast cancer cell migration and invasion. We asked if ZnR/GPR39 enhances breast cancer cell malignancy by activating KCC. Activation of ZnR/GPR39 by Zn²⁺ upregulated K⁺/Cl^- co-transport activity, measured using NH₄⁺ as a surrogate to K⁺ while monitoring intracellular pH. Upregulation of NH₄⁺ transport was monitored in tamoxifen resistant cells with functional ZnR/GPR39-dependent Ca²⁺ signaling but not in MCF-7 cells lacking this response. The NH₄⁺ transport was Na⁺-independent, and we therefore focused on KCC family members. Silencing of KCC3, but not KCC4, expression abolished Zn²⁺-dependent K⁺/Cl^- co-transport, suggesting that KCC3 is mediating upregulated NH₄⁺ transport. The ZnR/GPR39-dependent KCC3 activation accelerated scratch closure rate, which was abolished by inhibiting KCC transport with [(DihydroIndenyl) Oxy] Alkanoic acid (DIOA). Importantly, silencing of either ZnR/GPR39 or KCC3 attenuated Zn²⁺-dependent scratch closure. Thus, a novel link between KCC3 and Zn²⁺, via ZnR/GPR39, promotes breast cancer cell migration and proliferation.

A mixed methods randomised control trial to evaluate the effectiveness of the journey to social inclusion - phase 2 intervention for chronically homeless adults: study protocol

Background

Chronic homelessness is a problem characterised by longstanding inability to attain or maintain secure accommodation. Longitudinal research with homeless populations is challenging, and randomised controlled trials that evaluate the effectiveness of intensive, case management interventions aimed at improving housing and health-related outcomes for chronically homelessness people are scant. More research is needed to inform programmatic design and policy frameworks in this area. This study protocol details an evaluation of the Journey to Social Inclusion – Phase 2 program, an intervention designed to reduce homelessness and improve outcomes in chronically homeless adults.

Methods/design

J2SI Phase 2 is a three-year, mixed methods, multi-site, RCT that enrolled 186 participants aged 25 to 50 years between 07 January 2016 and 30 September 2016 in Melbourne. The intervention group (n = 90 recruited) receives the J2SI Phase 2 program, a trauma-informed intervention that integrates intensive case management and service coordination; transition to housing and support to sustain tenancy; and support to build social connections, obtain employment and foster independence. The comparison group (n = 96 recruited) receives standard service provision. Prior to randomisation, participants completed a baseline survey. Follow-up surveys will be completed every six months for three years (six in total). In addition to self-report data on history of homelessness and housing, physical and mental health, substance use, quality of life, social connectedness and public service utilisation, linked administrative data on participants’ public services utilisation (e.g., hospitalisation, justice system) will be obtained for the three-year period pre- and post-randomisation. Semi-structured, qualitative interviews will be conducted with a randomly selected subset of participants and service providers at three time-points to explore changes in key outcome variables and to examine individual experiences with the intervention and standard service provision. An economic evaluation of the intervention and associated costs will also be undertaken.

Discussion

Results of this trial will provide robust evidence on the effectiveness of J2SI Phase 2 compared to standard service provision. If the intervention demonstrates effectiveness in improving housing, health, quality-of-life, and other social outcomes, it may be considered for broader national and international dissemination to improve outcomes among chronically homeless adults.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12616000162415 (retrospectively registered 10-February-2016).

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6644-1) contains supplementary material, which is available to authorized users.

Nonsteroidal Anti-Inflammatory Drug Prescriptions Are Associated With Increased Stress Fracture Diagnosis in the US Army Population

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 American Society for Bone and Mineral Research.