The British Services Dhaulagiri Medical Research Expedition 2016: a unique military and civilian research collaboration.

INTRODUCTION: High-altitude environments lead to a significant physiological challenge and disease processes which can be life threatening; operational effectiveness at high altitude can be severely compromised. The UK military research is investigating ways of mitigating the physiological effects of high altitude. METHODS: The British Service Dhaulagiri Research Expedition took place from March to May 2016, and the military personnel were invited to consent to a variety of study protocols investigating adaptation to high altitudes and diagnosis of high-altitude illness. The studies took place in remote and austere environments at altitudes of up to 7500 m. RESULTS: This paper gives an overview of the individual research protocols investigated, the execution of the expedition and the challenges involved. 129 servicemen and women were involved at altitudes of up to 7500 m; 8 research protocols were investigated. CONCLUSIONS: The outputs from these studies will help to individualise the acclimatisation process and inform strategies for pre-acclimatisation should troops ever need to deploy at high altitude at short notice.

Incidence, prevalence and consequences of illness in academy rugby league players.

OBJECTIVES: To assess the incidence, prevalence and consequences of illness in one professional academy rugby league club during an in-season period. DESIGN: Observational prospective cohort study. METHOD: Seventeen male rugby league players (age 17.7±0.7 years, stature 178.8±5.1cm, body mass 87.2±9.6kg) completed a weekly self-report illness questionnaire using an amended version of the Oslo Sports Trauma Research Centre (OSTRC) questionnaire on health problems. RESULTS: A total of 24 new illnesses were reported over the 25-week study period. 65% of players experienced at least one illness during the study. The incidence of illness in this cohort was 14.3 per 1000-player days, with the respiratory system being most commonly affected (n=15; 62.5%). The average weekly illness prevalence was 10.3%. Time-loss illness incidence was 1.4 per 1000-player days. Loss of body mass and sleep disruptions were the most commonly reported consequences of illness episodes. Mean body mass loss during a period of illness was 2.2±0.6kg. CONCLUSIONS: Academy rugby league players are most commonly affected by respiratory illness with a total of nineteen training and competition days lost to illness. Associated consequences of illness, such as loss of body mass and sleep disruptions may present a challenge and negatively impact a rugby league player's development. Appropriate medical provisions should be provided for Academy rugby league players to support them during periods of illness to limit the impact of these consequences.

The effect of high altitude on central blood pressure and arterial stiffness.

Central arterial systolic blood pressure (SBP) and arterial stiffness are known to be better predictors of adverse cardiovascular outcomes than brachial SBP. The effect of progressive high altitude (HA) on these parameters has not been examined. Ninety healthy adults were included. Central BP and the augmentation index (AI) were measured at the level of the brachial artery (Uscom BP+ device) at <200 m and at 3619, 4600 and 5140 m. The average age of the subjects (70% men) were 32.2±8.7 years. Compared with central arterial pressures, brachial SBP (+8.1±6.4 mm Hg; P<0.0001) and pulse pressure (+10.9±6.6 mm Hg; P<0.0001) were significantly higher and brachial diastolic BP was lower (-2.8±1.6 mm Hg; P<0.0001). Compared with <200 m, HA led to a significant increase in brachial and central SBP. Central SBP correlated with AI (r=0.50; 95% confidence interval (CI): 0.41-0.58; P<0.0001) and age (r=0.32; 95% CI: 21-0.41; P<0.001). AI positively correlated with age (r=0.39; P<0.001) and inversely with subject height (r=-0.22; P<0.0001), weight (r=-0.19; P=0.006) and heart rate (r=-0.49; P<0.0001). There was no relationship between acute mountain sickness scores (Lake Louis Scoring System (LLS)) and AI or central BP. The independent predictors of central SBP were male sex (coefficient, t=4.7; P<0.0001), age (t=3.6; P=0.004) and AI (t=7.5; P<0.0001; overall r2=0.40; P<0.0001). Subject height (t=2.4; P=0.02), age (7.4; P<0.0001) and heart rate (t=11.4; P<0.0001) were the only independent predictors of AI (overall r2=0.43; P<0.0001). Central BP and AI significantly increase at HA. This rise was influenced by subject-related factors and heart rate but not independently by altitude, LLS or SpO2.

Serum cholesterol and colorectal polyps.

Colorectal cancer and hypocholesterolemia have recently been associated, and colorectal polyps have a known relationship with colorectal cancer. In order to establish further evidence regarding the nature of the serum cholesterol-colorectal cancer relationship, this study investigated the hypothesis that men with colorectal polyps would have lower serum cholesterol levels than men without polyps. Of the 1380 men screened by sigmoidoscopy for colorectal polyps, 246 had at least one polyp. The men with polyps were older than those without, and also had higher cholesterol levels, but after controlling for age, there were no serum cholesterol differences. These data suggest that low serum cholesterol is not etiologically linked to cancer. Analyses of potentially confounding variables showed smoking to be strongly related to the presence of polyps.

Prevalence of colorectal polyps among Michigan pattern and model makers.

A group of 902 pattern and model makers were screened for colorectal cancer and polyps using a 60-cm flexible sigmoidoscope. Three recent mortality studies have found a significant excess of colorectal malignant neoplasms in this occupational group. Four adenocarcinomas, two carcinoids, and two cancers in situ were found. In addition, 150 (17%) of the individuals were found to have polyps. Among white males 40 to 70 years of age, the prevalence rate was found to be 23%. The prevalence of colorectal polyps among the pattern and model makers was compared with that of four previously studied asymptomatic populations who were also examined using a 60-cm flexible sigmoidoscope. Polyp rates were found to be significantly greater among pattern and model makers than among three of the four comparison populations. The odds ratios between these three populations and the study population ranged from 1.9 to 2.7 and closely approximate the ratios found in previous studies evaluating colon cancer in this occupational group.