What do environment-related illnesses tell us about the character of military medicine and future clinical requirements?

Extreme environments present medical and occupational challenges that extend beyond generic resuscitation, to formulating bespoke diagnoses and prognoses and embarking on management pathways rarely encountered in civilian practice. Pathophysiological complexity and clinical uncertainty call for military physicians of all kinds to balance intuition with pragmatism, adapting according to the predominant patterns of care required. In an era of smaller operational footprints and less concentrated clinical experience, proposals aimed at improving the systematic care of Service Personnel incapacitated at environmental extremes must not be lost to corporate memory. These general issues are explored in the particular context of thermal stress and metabolic disruption. Specific focus is given to the accounts of military physicians who served on large-scale deployments into the heat of Iraq and Kuwait (Operation TELIC) and Oman (Exercise SAIF SAREEA). Generalisable insights into the enduring character of military medicine and future clinical requirements result.

Increase in hypoglycaemia and hyperglycaemia in people with diabetes admitted to hospital during COVID-19 pandemic

BACKGROUND

We used detailed information on patients with diabetes admitted to hospital to determine differences in clinical outcomes before and during the COVID-19 pandemic in the UK.

METHODS

The study used electronic patient record data from Imperial College Healthcare NHS Trust. Hospital admission data for patients coded for diabetes was analysed over three time periods: pre-pandemic (31st January 2019-31st January 2020), Wave 1 (1st February 2020-30th June 2020), and Wave 2 (1st September 2020-30th April 2021). We compared clinical outcomes including glycaemia and length of stay.

RESULTS

We analysed data obtained from 12,878, 4008 and 7189 hospital admissions during the three pre-specified time periods. The incidence of Level 1 and Level 2 hypoglycaemia was significantly higher during Waves 1 and 2 compared to the pre-pandemic period (25 % and 25.1 % vs. 22.9 % for Level 1 and 11.7 % and 11.5 % vs. 10.3 % for Level 2). The incidence of hyperglycaemia was also significantly higher during the two waves. The median hospital length of stay increased significantly (4.1[1.6, 9.8] and 4.0[1.4, 9.4] vs. 3.5[1.2, 9.2] days).

CONCLUSIONS

During the COVID-19 pandemic in the UK, hospital in-patients with diabetes had a greater number of hypoglycaemic/hyperglycaemic episodes and an increased length of stay when compared to the pre-pandemic period. This highlights the necessity for a focus on improved diabetes care during further significant disruptions to healthcare systems and ensuring minimisation of the impact on in-patient diabetes services.

SUMMARY

Diabetes is associated with poorer outcomes from COVID-19. However the glycaemic control of inpatients before and during the COVID-19 pandemic is unknown. We found the incidence of hypoglycaemia and hyperglycaemia was significantly higher during the pandemic highlighting the necessity for a focus on improved diabetes care during further pandemics.

A game for all shapes and sizes? Changes in anthropometric and performance measures of elite professional rugby union players 1999–2018

Background

Rugby union player size has increased since the game turned professional in 1995. Changes in physical and performance capability over this period have yet to be fully described.

Hypothesis

Increases in player momentum would result from changes in body mass.

Methods

Within-player rates of change in anthropometric and kinetic variables with season played were sampled in three successively studied professional rugby union club cohorts playing at the highest level of European competition between 1999 and 2019. Data comprised 910 seasons of observation for 291 elite male players. Most players had 2, 3 or 4 seasons of observation. Mixed-effects modelling distinguished changes independent of position played, club and international status.

Results

With each season played, player body mass, fat-free mass and maximum speed increased significantly, while per cent fat decreased. The mean maximal velocity of a rugby player in 1999 was 8.2 (±0.18) m/s, which in 2019 had risen to 9.1 (±0.10) m/s. Player’s momentum in 2019 was 14% more than those playing in 1999. In the Front Five, momentum increased in this period by >25%, mainly driven by greater running speed, disproving our hypothesis.

Conclusions

The momentum of players, particularly forwards, increased markedly over 20 seasons of professional rugby. The resulting forces generated in collisions are thus significantly greater, although these may be mitigated by better player conditioning. Proactive regulation to address player safety may be required to address the changing nature of anthropometric measures and physical performance, minimising injury rates and potential long-term sequelae.

Relative changes in brain and kidney biomarkers with Exertional Heat Illness during a cool weather marathon

Background

Medical personnel may find it challenging to distinguish severe Exertional Heat Illness (EHI), with attendant risks of organ-injury and longer-term sequalae, from lesser forms of incapacity associated with strenuous physical exertion. Early evidence for injury at point-of-incapacity could aid the development and application of targeted interventions to improve outcomes. We aimed to investigate whether biomarker surrogates for end-organ damage sampled at point-of-care (POC) could discriminate EHI versus successful marathon performance.

Methods

Eight runners diagnosed as EHI cases upon reception to medical treatment facilities and 30 successful finishers of the same cool weather marathon (ambient temperature 8 rising to 12 ºC) were recruited. Emerging clinical markers associated with injury affecting the brain (neuron specific enolase, NSE; S100 calcium-binding protein B, S100β) and renal system (cystatin C, cysC; kidney-injury molecule-1, KIM-1; neutrophil gelatinase-associated lipocalin, NGAL), plus copeptin as a surrogate for fluid-regulatory stress, were sampled in blood upon marathon collapse/completion, as well as beforehand at rest (successful finishers only).

Results

Versus successful finishers, EHI showed significantly higher NSE (10.33 [6.37, 20.00] vs. 3.17 [2.71, 3.92] ug.L-1, P<0.0001), cysC (1.48 [1.10, 1.67] vs. 1.10 [0.95, 1.21] mg.L-1, P = 0.0092) and copeptin (339.4 [77.0, 943] vs. 18.7 [7.1, 67.9] pmol.L-1, P = 0.0050). Discrimination of EHI by ROC (Area-Under-the-Curve) showed performance that was outstanding for NSE (0.97, P<0.0001) and excellent for copeptin (AUC = 0.83, P = 0.0066).

Conclusions

As novel biomarker candidates for EHI outcomes in cool-weather endurance exercise, early elevations in NSE and copeptin provided sufficient discrimination to suggest utility at point-of-incapacity. Further investigation is warranted in patients exposed to greater thermal insult, followed up over a more extended period.

Nutritional support for a person with type 1 diabetes undertaking endurance swimming

Long distance and open water swimming have increased in popularity over recent years. Swimming a long distance in lakes, rivers and the sea present numerous challenges, including cold water exposure and maintaining adequate nutritional intake to fuel exercising muscles. Guidelines exist outlining issues to consider and potential solutions to overcome the difficulties in feeding athletes. Exercising with type 1 diabetes adds further complexity, mostly around matching insulin to the recommended high carbohydrate intake, but also because of the way in which higher circulating insulin levels affect glucose utilisation and fat oxidation. This paper describes the nutritional considerations for people with type 1 diabetes intending to undertake long distance open water events, and insulin management suggestions to trial alongside. In addition, we include personal testimony from a swimmer with type 1 diabetes describing the challenges and considerations he faced when undertaking marathon swimming.

Improved glycaemia during the Covid-19 pandemic lockdown is sustained post-lockdown and during the "Eat Out to Help Out" Government Scheme, in adults with Type 1 diabetes in the United Kingdom

AIMS

The majority of studies report that the Covid-19 pandemic lockdown did not have a detrimental effect on glycaemia. We sought to explore the impact of lockdown on glycaemia and whether this is sustained following easing of restrictions.

METHODS

Retrospective, observational analysis in adults and children with type 1 diabetes attending a UK specialist centre, using real-time or intermittently scanned continuous glucose monitoring. Data from the following 28-day time periods were collected: (i) pre-lockdown; (ii) during lockdown; (iii) immediately after lockdown; and (iv) a month following relaxation of restrictions (coinciding with Government-subsidised restaurant food). Data were analysed for times in glycaemic ranges and are expressed as median (IQR).

RESULTS

145 adults aged 35.5 (25.8-51.3) years with diabetes duration of 19.0 (7.0-29.0) years on multiple daily injections of insulin (60%) and continuous insulin infusion (40%) were included. In adults, % time in range (70-180mg/dL) increased during lockdown (60.2 (45.2-69.3)%) compared to pre-lockdown (56.7 (43.5-65.3)%; p<0.001). This was maintained in the post-lockdown time periods. Similarly, % time above range (>180mg/dL) reduced in lockdown compared to pre-lockdown (p = 0.01), which was sustained thereafter. In children, no significant changes to glycaemia were observed during lockdown. In multivariable analysis, a greater increase in %TIR 3.9-10mmol/L (70-180mg/dL) during lockdown was associated with higher levels of deprivation (coefficient: 4.208, 95% CI 0.588 to 7.828; p = 0.02).

CONCLUSIONS

Glycaemia in adults improved during lockdown, with people from more deprived areas most likely to benefit. This effect was sustained after easing of restrictions, with government-subsidised restaurant eating having no adverse impact on glycaemia.

Adverse outcomes in COVID-19 and diabetes: a retrospective cohort study from three London teaching hospitals

INTRODUCTION

Patients with diabetes mellitus admitted to hospital with COVID-19 have poorer outcomes. However, the drivers of poorer outcomes are not fully elucidated. We performed detailed characterization of patients with COVID-19 to determine the clinical and biochemical factors that may be drivers of poorer outcomes.

RESEARCH DESIGN AND METHODS

This is a retrospective cohort study of 889 consecutive inpatients diagnosed with COVID-19 between March 9 and April 22, 2020 in a large London National Health Service Trust. Unbiased multivariate logistic regression analysis was performed to determine variables that were independently and significantly associated with increased risk of death and/or intensive care unit (ICU) admission within 30 days of COVID-19 diagnosis.

RESULTS

62% of patients in our cohort were of non-white ethnic background and the prevalence of diabetes was 38%. 323 (36%) patients met the primary outcome of death/admission to the ICU within 30 days of COVID-19 diagnosis. Male gender, lower platelet count, advancing age and higher Clinical Frailty Scale (CFS) score (but not diabetes) independently predicted poor outcomes on multivariate analysis. Antiplatelet medication was associated with a lower risk of death/ICU admission. Factors that were significantly and independently associated with poorer outcomes in patients with diabetes were coexisting ischemic heart disease, increasing age and lower platelet count.

CONCLUSIONS

In this large study of a diverse patient population, comorbidity (ie, diabetes with ischemic heart disease; increasing CFS score in older patients) was a major determinant of poor outcomes with COVID-19. Antiplatelet medication should be evaluated in randomized clinical trials among high-risk patient groups.

Is there a need to measure preand post-capillary blood glucose following a cardiac exercise class?

Exercise training is associated with positive health outcomes in people with cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). However, fear of hypoglycaemia is a potential barrier to participants attending a cardiac exercise class. Therefore, we assessed the capillary blood glucose (CBG) responses to the Imperial NHS Trust cardiac exercise class. Forty patients (median age 66 years, interquartile range [IQR] 57-74 years) with CVD and T2DM treated with insulin and/or sulfonylureas completed a cardiac exercise class. CBG was measured immediately before and after the exercise class. Subgroup analysis assessed CBG levels in patients who had consumed food <2 and ≥2 hours and had taken their insulin and/or sulfonylureas <4 and ≥4 hours before the exercise class. Overall, post-exercise CBG had significantly decreased (-3.0 mmol/L, p≤0.0001). Subgroup analyses demonstrated significant reductions in CBG in both food consumption groups (<2 hours -2.9 mmol/L, p≤0.0001, and ≥2 hours -3.1 mmol/L, p≤0.0001) and medication groups (<4 hours -3.4 mmol/L, p≤0.0002, and ≥4 hours -2.7 mmol/L, p≤0.0001). However, there were no significant differences in CBG between the food consumption groups and the medication groups, respectively (p=0.7 and p=0.3). Cardiac exercise classes resulted in significant reductions in CBG levels. However, the timing of food consumption or medication intake did not influence the magnitude of CBG decline after the cardiac exercise class.

Loss of association between HbA1c and vascular disease in older adults with type 1 diabetes

Aims

Robust evidence supports intensive glucose control in those with recently diagnosed type 1 diabetes to reduce the risk of developing micro- and macrovascular complications. Data to support longitudinal glycaemic targets is lacking. We aimed to explore if longer duration of diabetes and greater age might reduce the impact of glycaemia on the risk of vascular complications.

Research and design methods

Data for adults age 20 years or more, was extracted from a clinical database of people with type 1 diabetes cared for at a London teaching hospital. The presence or absence of micro- and macro-vascular complications was recorded. Multivariable logistic regression analysis was performed using HbA1c as independent variable, diabetes duration and age as continuous variable and obesity, hypertension, hypercholesterolaemia, low HDL cholesterol and hypertriglyceridaemia as categorical variables.

Results

Data from 495 patients was used. HbA1c above 60 mmol/mol (7.6%) was associated with increased microvascular complications in patients aged 20–44 years, independent of age and duration of diabetes. In older people with T1DM duration of diabetes was the major risk factor.

Conclusions

Our study suggests that increased age and greater duration of diabetes reduce the impact of glycaemia on the risk of vascular complications. Intensive blood glucose management in patients aged ≥45 years may have limited benefits in terms of reducing the risk of complications although this does not dismiss the benefits of good glycaemic control in older people with T1DM.

Mapping the Steroid Response to Major Trauma From Injury to Recovery: A Prospective Cohort Study

CONTEXT

Survival rates after severe injury are improving, but complication rates and outcomes are variable.

OBJECTIVE

This cohort study addressed the lack of longitudinal data on the steroid response to major trauma and during recovery.

DESIGN

We undertook a prospective, observational cohort study from time of injury to 6 months postinjury at a major UK trauma centre and a military rehabilitation unit, studying patients within 24 hours of major trauma (estimated New Injury Severity Score (NISS) > 15).

MAIN OUTCOME MEASURES

We measured adrenal and gonadal steroids in serum and 24-hour urine by mass spectrometry, assessed muscle loss by ultrasound and nitrogen excretion, and recorded clinical outcomes (ventilator days, length of hospital stay, opioid use, incidence of organ dysfunction, and sepsis); results were analyzed by generalized mixed-effect linear models.

FINDINGS

We screened 996 multiple injured adults, approached 106, and recruited 95 eligible patients; 87 survived. We analyzed all male survivors <50 years not treated with steroids (N = 60; median age 27 [interquartile range 24-31] years; median NISS 34 [29-44]). Urinary nitrogen excretion and muscle loss peaked after 1 and 6 weeks, respectively. Serum testosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate decreased immediately after trauma and took 2, 4, and more than 6 months, respectively, to recover; opioid treatment delayed dehydroepiandrosterone recovery in a dose-dependent fashion. Androgens and precursors correlated with SOFA score and probability of sepsis.

CONCLUSION

The catabolic response to severe injury was accompanied by acute and sustained androgen suppression. Whether androgen supplementation improves health outcomes after major trauma requires further investigation.

Undifferentiated febrile illnesses in South Sudan: a case series from Operation TRENTON from June to August 2017

Undifferentiated febrile illnesses present diagnostic and treatment challenges in the Firm Base, let alone in the deployed austere environment. We report a series of 14 cases from Operation TRENTON in South Sudan in 2017 that coincided with the rainy season, increased insect numbers and a Relief in Place. The majority of patients had headaches, myalgia, arthralgia and back pain, as well as leucopenia and thrombocytopenia. No diagnoses could be made in theatre, despite a sophisticated deployed laboratory being available, and further testing in the UK, including next-generation sequencing, was unable to establish an aetiology. Such illnesses are very likely to present in tropical environments, where increasing numbers of military personnel are being deployed, and clinicians must be aware of the non-specific presentation and treatment, as well as the availability of Military Infection Reachback services to assist in the management of these cases.

Hyponatraemia: the importance of obtaining a detailed history and corroborating point-of-care analysis with laboratory testing

We describe a 67-year-old man admitted from a mental health unit with an incidental finding of hyponatraemia on routine blood tests. Laboratory investigations were in keeping with syndrome of inappropriate antidiuretic hormone secretion (SIADH). He had been recently commenced on mirtazapine. During his inpatient stay, he became increasingly confused. Review of a previous admission with hyponatraemia raised the possibility of voltage-gated potassium channel antibody-associated limbic encephalitis, although subsequent investigations deemed this unlikely as a cause of hyponatraemia. Although his sodium levels improved with fluid restriction, serial point-of-care testing proved misleading in monitoring the efficacy of treatment as inconsistencies were seen in comparison with laboratory testing. The cause of hyponatraemia may have been medication-induced SIADH and/or polydipsia. This case highlights the importance of collating detailed histories and laboratory blood testing to guide management in cases of hyponatraemia of unknown aetiology.

Cheiroarthropathy and tendinopathy in diabetes

Joint problems commonly occur in people with diabetes. Cheiroarthropathy affects the hands and results in painless limited finger joint extension, appearing to be associated with longer diabetes duration and the presence of microvascular complications. The prevalence of cheiroarthropathy seems to be falling, perhaps as a result of improvements in glycaemic management. Non-enzymatic glycation of collagen results in abnormally crosslinked protein resistant to degradation with subsequent increased build-up of collagen in joints. The management of cheiroarthropathy is predominantly conservative, with occupational and hand therapy at the forefront. Tendinopathy is more common in people with diabetes than those without, and is associated with obesity and insulin resistance. As with cheiroarthropathy, the exact causative mechanism of tendinopathy in diabetes is not known, but may be linked to inflammation, apoptosis and increased vascularity of affected tendons, driven by hyperinsulinaemia. Local fat pads have also been suggested to play a role in the pathogenesis of tendinopathy.

Variation in renal responses to exercise in the heat with progressive acclimatisation

OBJECTIVES

To investigate changes in renal status from exercise in the heat with acclimatisation and to evaluate surrogates markers of Acute Kidney Injury.

DESIGN

Prospective observational cohort study.

METHODS

20 male volunteers performed 60 min standardised exercise in the heat, at baseline and on four subsequent occasions during a 23-day acclimatisation regimen. Blood was sampled before and after exercise for serum creatinine, copeptin, interleukin-6, normetanephrine and cortisol. Fractional excretion of sodium was calculated for corresponding urine samples. Ratings of Perceived Exertion were reported every 5 min during exercise. Acute Kidney Injury was defined as serum creatinine rise ≥26.5 μmol L^-1 or fall in estimated glomerular filtration rate >25%. Predictive values of each candidate marker for developing Acute Kidney Injury were determined by ROC analysis.

RESULTS

From baseline to Day 23, serum creatinine did not vary at rest, but showed a significant (P<0.05) reduction post-exercise (120 [102, 139] versus 102 [91, 112] μmol L^-1). Acute Kidney Injury was common (26/100 exposures) and occurred most frequently in the unacclimatised state. Log-normalised fractional excretion of sodium showed a significant interaction (exercise by acclimatization day), with post-exercise values tending to rise with acclimatisation. Ratings of Perceived Exertion predicted AKI (AUC 0.76, 95% confidence interval 0.65-0.88), performing at least as well as biochemical markers.

CONCLUSIONS

Heat acclimatization is associated with reduced markers of renal stress and AKI incidence, perhaps due to improved regional perfusion. Acclimatisation and monitoring Ratings of Perceived Exertion are practical, non-invasive measures that could help to reduce renal injury from exercise in the heat.

Clinical activity at the UK military level 2 hospital in Bentiu, South Sudan during Op TRENTON from June to September 2017

Introduction

Diseases and non-battle injuries (DNBIs) are common on UK military deployments, but the collection and analysis of clinically useful data on these remain a challenge. Standard medical returns do not provide adequate clinical information, and clinician-led approaches have been laudable, but not integrated nor standardised nor used long-term. Op TRENTON is a novel UK military humanitarian operation in support of the United Nations Mission in South Sudan, which included the deployment of UK military level 1 and level 2 medical treatment facilities at Bentiu to provide healthcare for UK and United Nations (UN) personnel.

Methods

A service evaluation of patient consultations and admissions at the UK military level 2 hospital was performed using two data sets collected by the emergency department (ED) and medicine (MED) teams.

Results

Over a three-month (13-week) period, 286 cases were seen, of which 51% were UK troops, 29% were UN civilians and 20% were UN troops. The ED team saw 175 cases (61%) and provided definitive care for 113 (40%), whereas the MED team saw and provided definitive care for 128 cases (45%). Overall, there were 75% with diseases and 25% with non-battle injuries. The most common diagnoses seen by the ED team were musculoskeletal injuries (17%), unidentified non-malarial undifferentiated febrile illness (UNMUFI) (17%), malaria (13%), chemical pneumonitis (13%) and wounds (8%). The most common diagnoses seen by the MED team were acute gastroenteritis (AGE) (56%), UNMUFI (12%) and malaria (9%). AGE was due to viruses (31%), diarrhoeagenic Escherichia coli (32%), other bacteria (6%) and protozoa (12%).

Conclusion

Data collection on DNBIs during the initial phase of this deployment was clinically useful and integrated between different departments. However, a standardised, long-term solution that is embedded into deployed healthcare is required. The clinical activity recorded here should be used for planning, training, service development and targeted research.

Protein recycling and limb muscle recovery after critical illness in slow- and fast-twitch limb muscle

An impaired capacity of muscle to regenerate after critical illness results in long-term functional disability. We previously described in a long-term rat peritonitis model that gastrocnemius displays near-normal histology whereas soleus demonstrates a necrotizing phenotype. We thus investigated the link between the necrotizing phenotype of critical illness myopathy and proteasome activity in these two limb muscles. We studied male Wistar rats that underwent an intraperitoneal injection of the fungal cell wall constituent zymosan or n-saline as a sham-treated control. Rats (n = 74) were killed at 2, 7, and 14 days postintervention with gastrocnemius and soleus muscle removed and studied ex vivo. Zymosan-treated animals displayed an initial reduction of body weight but a persistent decrease in mass of both lower hindlimb muscles. Zymosan increased chymotrypsin- and trypsin-like proteasome activities in gastrocnemius at days 2 and 7 but in soleus at day 2 only. Activated caspases-3 and -9, polyubiquitin proteins, and 14-kDa fragments of myofibrillar actin (proteasome substrates) remained persistently increased from day 2 to day 14 in soleus but not in gastrocnemius. These results suggest that a relative proteasome deficiency in soleus is associated with a necrotizing phenotype during long-term critical illness. Rescuing proteasome clearance may offer a potential therapeutic option to prevent long-term functional disability in critically ill patients.

Changes in northern hemisphere male international rugby union players' body mass and height between 1955 and 2015

Objectives

We sought to establish the effects of professionalism, which officially began in 1995, on the body mass and height of northern hemisphere male international rugby union (RU) players. We hypothesised that mass would significantly increase following professionalism. We also investigated the changes in size of players according to their playing position, and we compared changes to rugby league (RL) players and the public.

Methods

The body mass and height of players representing their international team for that country’s first game of the Five Nations in 1955, 1965, 1975, 1985 and 1995 and, for 2005 and 2015, the Six Nations, were collected from matchday programmes. RL players’ data were collected from the Challenge Cup final games played in the same years.

Results

International RU player body mass has significantly increased since 1995. In 1955 mean (±SD) player body mass was 84.8  kg (±8.2); in 2015, it was 105.4  kg (±12.1), an increase of 24.3%. Between 1955 and 2015, the body mass of forwards increased steadily, whereas that of backs has mostly gone up since 1995. RU player body mass gain has exceeded that of RL, but the age-matched difference between RU players and the public has remained relatively constant.

Conclusions

The factors influencing the gain in body mass of rugby players are legion; however, we believe that the interpretation of the law relating to the scrum put-in and changes allowing substitutions have, at least in part, contributed to the observed changes. Injury severity is increasing, and this may be linked to greater forces (caused by greater body mass) occurring in contact. RU law makers should adjust the rules to encourage speed and skill at the expense of mass.

Managing diabetes at high altitude: personal experience with support from a Multidisciplinary Physical Activity and Diabetes Clinic

OBJECTIVE

Physical activity is important for well-being but can be challenging for people with diabetes. Data informing support of specialist activities such as climbing and high-altitude trekking are limited. A 42-year-old man with type 1 diabetes (duration 30 years) attended a Multidisciplinary Physical Activity and Diabetes Clinic planning to climb Mont Blanc during the summer and trek to Everest Base Camp in the autumn. His aims were to complete these adventures without his diabetes impacting on their success.

METHODS

We report the information provided that enabled him to safely facilitate his objectives, in particular, the requirement for frequent checking of blood glucose levels, the effects of altitude on insulin dose requirements, and recognition that acute mountain sickness may mimic the symptoms of hypoglycaemia and vice versa. Real-time continuous glucose monitoring was made available for his treks.

RESULTS

The effects of high altitude on blood glucose results and glycaemic variability while treated on multiple daily injections of insulin are reported. In addition, we present a first-person account of his experience and lessons learnt from managing diabetes at high altitude.

CONCLUSIONS

A dedicated Multidisciplinary Physical Activity and Diabetes Clinic delivering individualised, evidence-based, patient-focused advice on the effects of altitude on blood glucose levels, and provision of real-time continuous glucose monitoring enabled uneventful completion of a trek to Everest Base Camp in a person with type 1 diabetes.

Biochemical, Physiological and Psychological Changes During Endurance Exercise in People With Type 1 Diabetes

BACKGROUND

Increasing numbers of people with diabetes are adopting exercise programs. Fear of hypoglycemia, hypoglycemia itself, and injuries are major issues for many people with diabetes undertaking physical activity. The purpose of this study was to investigate the effects of type 1 diabetes mellitus on the risk of hypoglycemia, glycemic variability, exercise performance, changes in body composition, changes in insulin dosage, and psychosocial well-being during a multiday endurance exercise event.

METHODS

Eleven participants (7 with type 1 diabetes, 4 with normal glucose tolerance) undertook a 15-day, 2300 km cycling tour from Barcelona to Vienna. Data were prospectively collected using bike computers, continuous glucose monitors, body composition analyzers, and mood questionnaires.

RESULTS

Mean blood glucose in riders with and without diabetes significantly reduced as the event progressed. Glycemic variability and time spent in hypoglycemia did not change throughout the ride for either set of riders. Riders with diabetes in the lowest quartile of sensor glucose values had significantly reduced power output. Percentage body fat also significantly fell. Hypo- and hyperglycemia provoked feelings of anxiety and worry.

CONCLUSIONS

This is the first study to describe a real-time endurance event in type 1 diabetes, and provides important new data that cannot be studied in laboratory conditions. Hypoglycemia continues to occurs in spite of peer support and large reductions in insulin dose. Glycemic variability is shown as a potential barrier to participation in physical activity through effects on mood and psychological well-being.

Changes in gut hormones and leptin in military personnel during operational deployment in Afghanistan

OBJECTIVE

Understanding the mechanisms that drive weight loss in a lean population may elucidate systems that regulate normal energy homeostasis. This prospective study of British military volunteers investigated the effects of a 6-month deployment to Afghanistan on energy balance and circulating concentrations of specific appetite-regulating hormones.

METHODS

Measurements were obtained twice in the UK (during the Pre-deployment period) and once in Afghanistan, at Mid-deployment. Body mass, body composition, food intake, and appetite-regulatory hormones (leptin, active and total ghrelin, PYY, PP, GLP-1) were measured.

RESULTS

Repeated measures analysis of 105 volunteers showed body mass decreased by 4.9% ± 3.7% (P < 0.0001) during the first half of the deployment. Leptin concentrations were significantly correlated with percentage body fat at each time point. The reduction in percentage body fat between Pre-deployment and Mid-deployment was 8.6%, with a corresponding 48% decrease in mean circulating leptin. Pre-deployment leptin and total and active ghrelin levels correlated with subsequent change in body mass; however. no changes were observed in the anorectic gut hormones GLP-1, PP, or PYY.

CONCLUSIONS

These data suggest that changes in appetite-regulating hormones in front line military personnel occur in response to, but do not drive, reductions in body mass.

Nutrition research in the military

Military research performed in an operational environment involves mission-specific considerations. The Institute of Naval Medicine was tasked in 2008 by the Surgeon General to investigate the nutritional status of deployed British military personnel, and how this might affect body composition, physical fitness and operational capability. This paper briefly describes the logistic and technical issues specific to military research that were encountered by the study team, how these issues were overcome and how this research has influenced military practice.

Energy at high altitude

For the military doctor, an understanding of the metabolic effects of high altitude (HA) exposure is highly relevant. This review examines the acute metabolic challenge and subsequent changes in nutritional homeostasis that occur when troops deploy rapidly to HA. Key factors that impact on metabolism include the hypoxic-hypobaric environment, physical exercise and diet. Expected metabolic changes include augmentation of basal metabolic rate (BMR), decreased availability of oxygen in peripheral metabolic tissues, reduction in VO2 max, increased glucose dependency and lactate accumulation during exercise. The metabolic demands of exercise at HA are crucial. Equivalent activity requires greater effort and more energy than it does at sea level. Soldiers working at HA show high energy expenditure and this may exceed energy intake significantly. Energy intake at HA is affected adversely by reduced availability, reduced appetite and changes in endocrine parameters. Energy imbalance and loss of body water result in weight loss, which is extremely common at HA. Loss of fat predominates over loss of fat-free mass. This state resembles starvation and the preferential primary fuel source shifts from carbohydrate towards fat, reducing performance efficiency. However, these adverse effects can be mitigated by increasing energy intake in association with a high carbohydrate ration. Commanders must ensure that individuals are motivated, educated, strongly encouraged and empowered to meet their energy needs in order to maximise mission-effectiveness.

Importance of accounting for the variability of electrocardiographic data among diagnostically similar patients with inferior wall healed myocardial infarction

The authors describe a method to account for patient-to-patient variability in electrocardiographic data. The method yielded criteria for healed inferior myocardial infarction with diagnostic performances better than those of traditional electrocardiographic parameters.

A mediational model of the impact of interparental conflict on child adjustment in a multiethnic, low-income sample

Path analysis was used to determine whether the effects of interparental conflict on children's depression and conduct disorder are mediated by 3 dimensions of parenting: acceptance, inconsistent discipline, and hostile control. The study extends the literature by testing this mediational model with a low-income, predominantly ethnic minority sample of preadolescent children and by examining the effects of multiple dimensions of interparental conflict from the child's perspective. Results supported the mediational model when analyses were based on child's reports of all variables but not when mother's reports were used to assess child depression and conduct problems. Exploratory analyses revealed unique mediational paths associated with conflict frequency and resolution, which were examined along with intensity as distinct dimensions of interparental conflict.

Using digital versus analog ECG data in clinical trials

In 54 patients, we measured 3 different electrocardiogram (ECG) parameters required in the Symphony 1 trial and compared various combinations of pairs of measurements from 4 different sets of analog data and 1 set of digital data. Particularly for measurements of the durations of R waves in lead aVF, we found poor intraobserver and interobserver reliability and poor agreement between analog and digital data. There was much better agreement in measurements of the amplitudes of S waves in lead V3. The poorer agreement involving durations appears to be due to difficulties in accurately identifying the offsets of portions of the QRS complex, especially in lead AVF. We conclude that, particularly in measurements of duration, digital and analog data are not equivalent.

Hormonal response to orthostasis in elderly people with systemic systolic hypertension

BACKGROUND

Orthostatic hypotension is a common phenomenon in the elderly. Hormonal changes during orthostatic stress have been described in elderly normotensive people and in those with essential hypertension. However, the hormonal response in elderly people who have systolic hypertension during orthostasis has not yet been quantified.

METHODS

In this study we investigated 14 non-diabetic men, aged 60 to 75 years, with untreated systolic hypertension who were subjected to 45 degrees passive head-up incline on a tilt table for 15 min. Their hormonal profile and hemodynamic changes were analyzed before and after the stress.

RESULTS

In the supine position, plasma levels of norepinephrine, atrial natriuretic peptide and aldosterone were in the normal range, while the plasma renin activity was low. Immediately upon tilt the systolic blood pressure fell but it reverted to baseline values after 15 min of orthostasis. At that time the cardiac output decreased while the systemic vascular resistance and the plasma norepinephrine concentration rose. The atrial natriuretic peptide appeared to fall, and the renin-aldosterone level did not change.

CONCLUSION

The physiologic response to orthostatic stress in elderly people with systolic hypertension is comparable to that of elderly normotensive people and those with essential hypertension, i.e. a decrease in cardiac output and an increase in plasma norepinephrine levels. The atrial natriuretic peptide appeared to fall appropriately. The response of the renin-aldosterone system mimicked that in elderly patients with low renin essential isolated hypertension. These observations may have a bearing on the management of elderly people with systolic hypertension who also have orthostatic symptoms; they may not require a different approach from that needed for others of the same age group.

Does parenting differ based on social class?: African American women's perceived socialization for achievement

Research has provided some evidence of ethnic group, gender, and class differences in the socialization for achievement. However, there is little research on African American women with the exception of the studies of low-income, single mothers. To understand the similarities and differences in socialization for achievement based on social class, middle-class African American women from working- and middle-class backgrounds were studied using qualitative and quantitative methods to compare them on issues related to achievement socialization. Women from middle-class backgrounds reported that their parents had higher expectations for them and were more involved in their education than did women from working-class backgrounds. More middle-class parents expected their daughters to be successful in careers than did working-class parents. Women from working-class families did receive support from their parents but they did not have as much support as did the women from middle-class backgrounds. Women from working-class families perhaps made use of other sources to support their desire to succeed. There were no differences in perceived race-related socialization based on social class. Implications of these findings for future research are discussed.

Baroreflex function during 45-degree passive head-up tilt before and after long-term thiazide therapy in the elderly with systolic systemic hypertension

The ratio of the 30th to the 15th cardiac cycle duration on an electrocardiogram (30:15 ratio) immediately after active standing from the supine position has been used as one of the markers of baroreflex function. A ratio of < or = 1.0 has been suggested to indicate baroreflex dysfunction. Blood pressure (BP) changes were measured and the 30:15 ratio was calculated after standing and during 45-degree passive head-up tilt from the supine position in 10 nondiabetic men (mean age +/- SE 70.1 +/- 1.05 years, and BP < 150/90 mm Hg). After tilt the decrease in systolic BP (from 132 +/- 4.8 to 117 +/- 6.3 mm Hg; p < 0.001) appeared to be larger than that after standing (from 132 +/- 4.6 to 123 +/- 5.8 mm Hg; p < 0.01), whereas the 30:15 ratios were 0.965 +/- 0.006 and 0.970 +/- 0.014, respectively, which suggested baroreflex dysfunction. Although the mean of the 2 ratios did not differ, the variance appeared to be less during tilting than after standing. Thus, the 45-degree passive head-up tilt appeared to be a better and more uniform inducer of orthostatic stress than active standing. Therefore, 45-degree head-up tilt was used in a group of 10 nondiabetic male patients (aged 70 +/- 1.46 years) with isolated systolic hypertension (systolic BP > 160 mm Hg, diastolic BP of < 90 mm Hg) to assess their baroreflex function. Upon tilting, their systolic BP decreased from 190 +/- 5.5 to 179 +/- 5.8 mm Hg (p < 0.05) and their 30:15 ratio was 0.985 +/- 0.011.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic response to orthostatic stress in the elderly with systolic systemic hypertension before and after long-term thiazide therapy

The hemodynamic effects of orthostatic stress in elderly subjects with systolic hypertension were studied before and after long-term hydrochlorothiazide therapy (50 mg daily). Sixteen nondiabetic men aged 70 +/- 1 (SE) years participated in the study initially, and 12 completed 1 year of therapy. Patients underwent 45 degrees head-up incline on a tilt table before, after 1 month and after 1 year of therapy. Hemodynamic variables were measured in the following situations: (1) the supine position, (2) immediately after completion of passive 45 degrees head-up position at 0 minute, (3) at 15 minutes in the tilted state while patients performed intermittent foot movements to minimize gravitational pooling and simulate the standing position outside the laboratory, and (4) after returning to the supine position. Systolic and diastolic blood pressure (BP) decreased significantly after 1 month of therapy, and this reduction was maintained up to 1 year in all aforementioned body positions, with the exception of diastolic BP at 0 minute of tilt, which was significant at 1 year only. Before therapy was begun, there was a significant reduction in systolic BP immediately after completion of tilting; however, this was statistically insignificant both at 1 month and 1 year of therapy. Thus, the data may help dispel the concern of exacerbating the hypotensive response to orthostatic stress in patients with systolic hypertension after long-term thiazide diuretic therapy.

Mitral valve prolapse and neuroticism in chest pain patients with normal and diseased coronary arteries

Patients with chest pain and normal coronary arteries (NCA) score higher on measures of neuroticism than patients with coronary artery disease (CAD). This relationship, coupled with findings linking mitral valve prolapse (MVP) and anxiety disorders, led us to examine prospectively the possibility that a greater incidence of MVP among NCA patients accounts for their elevated neuroticism scores. One-hundred-forty-four patients completed psychological tests and a structured interview prior to cardiac catheterization. Forty-one of the 144 patients (28%) had normal coronary arteries. Within the NCA group 29 percent had MVP; within the CAD group only 13 percent had MVP. Despite the significant difference between NCA and CAD groups on measures of neuroticism, there were no differences as a function of MVP status, nor was there an interaction of MVP and coronary arterial status. These findings support the case for an association between NCA and neuroticism independent of the presence or absence of MVP.

One-year psychosocial follow-up of patients with chest pain and angiographically normal coronary arteries

As many as 30% of patients with chest pain symptoms who are referred for arteriography are found to have normal coronary arteries. Research has shown that patients with anginal symptoms and normal coronary arteries score higher on neuroticism measurements (anxiety, depression and somatic concerns) at the time of catheterization than patients with anginal symptoms who have coronary artery disease. Research examining the cardiac course of chest pain patients with normal coronary arteries indicates that this is a nonprogressive disorder. Although follow-up studies of these patients report continued chest pain and diminished physical activity, these studies have ignored the psychologic status of the patients. Thus, it is not known whether their higher neuroticism scores at the time of catheterization persist following angiography or whether such elevated indexes of neuroticism are transient phenomena associated with precatheterization anticipatory stress. The present study examined 48 Veterans Administration Medical Center patients: 24 with anginal symptoms and normal coronary arteries and 24 with documented coronary artery disease. The patients completed a structured clinical interview and a set of psychologic inventories on the day before catheterization and 1 year later. The findings established continued high neuroticism scores among patients with anginal symptoms only and supported the findings of other investigators regarding continuing chest pain and restricted physical activity. The knowledge alone of benign coronary artery status resulted in virtually no change in the psychosocial status of these patients. Alternative treatment methods are discussed.

Relationship between Doppler left ventricular diastolic filling indexes and the electrocardiographic criteria for left atrial enlargement

Traditional electrocardiographic (ECG) criteria for left atrial enlargement (LAE) emphasize the increased amplitude and width of the corresponding component of the hypertrophied atrium. Although a correlation exists between LAE and ECG criteria, a cause-and-effect relationship has not been conclusively demonstrated. Because the diastolic properties of the left ventricle directly influence left atrial emptying, these properties might also influence the ECG diagnosis of LAE. Therefore, the authors hypothesized that the ECG criteria for LAE are influenced by diastolic properties of the left ventricle as defined by Doppler-derived parameters.

Usefulness of abnormalities of repolarization in the electrocardiographic diagnosis of healed myocardial infarction

The authors evaluated the ability of criteria involving abnormalities of repolarization to diagnose healed myocardial infarction (MI). They studied the Q, R, S, and T waves and the ST-segments of the electrocardiograms (ECGs) of 60 angiographic-normal patients, 63 patients with angiographic evidence of healed inferior MI, and 33 patients with angiographic evidence of anterior MI. The best individual criteria involving repolarization were T wave amplitude less than or equal to 0.4 mm in lead II for inferior MI (specificity, 93%: sensitivity, 67%) and T wave amplitude greater than 2.4 mm for anterior MI (specificity, 100%: sensitivity, 27%). These T wave criteria enhanced the diagnostic performances of otherwise marginal QRS criteria for both inferior and anterior MI. The authors conclude that ECG criteria that involve abnormalities of the T waves are useful for diagnosing healed MI.