Hemispheric processing of memory is affected by sleep

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Sleep is known to affect learning and memory, but the extent to which it influences behavioural processing in the left and right hemispheres of the brain is as yet unknown. We tested two hypotheses about lateralised effects of sleep on recognition memory for words: whether sleep reactivated recent experiences of words promoting access to the long-term store in the left hemisphere (LH), and whether sleep enhanced spreading activation differentially in semantic networks in the hemispheres. In Experiment 1, participants viewed lists of semantically related words, then slept or stayed awake for 12 h before being tested on seen, unseen but related, or unrelated words presented to the left or the right hemisphere. Sleep was found to promote word recognition in the LH, and to spread activation equally within semantic networks in both hemispheres. Experiment 2 ensured that the results were not due to time of day effects influencing cognitive performance

Risk of Injury in Royal Air Force Training: Does Sex Really Matter?

IntroductionMusculoskeletal injuries are common during military and other occupational physical training programs. Employers have a duty of care to reduce employees’ injury risk, where females tend to be at greater risk than males. However, quantification of principle co-factors influencing the sex–injury association, and their relative importance, remain poorly defined. Injury risk co-factors were investigated during Royal Air Force (RAF) recruit training to inform the strategic prioritization of mitigation strategies.Material and MethodsA cohort of 1,193 (males n = 990 (83%); females n = 203 (17%)) recruits, undertaking Phase-1 military training, were prospectively monitored for injury occurrence. The primary independent variable was sex, and potential confounders (fitness, smoking, anthropometric measures, education attainment) were assessed pre-training. Generalized linear models were used to assess associations between sex and injury.ResultsIn total, 31% of recruits (28% males; 49% females) presented at least one injury during training. Females had a two-fold greater unadjusted risk of injury during training than males (RR = 1.77; 95% CI 1.49–2.10). After anthropometric, lifestyle and education measures were included in the model, the excess risk decreased by 34%, but the associations continued to be statistically significant. In contrast, when aerobic fitness was adjusted, an inverse association was identified; the injury risk was 40% lower in females compared with males (RR = 0.59; 95% CI: 0.42–0.83).ConclusionsPhysical fitness was the most important confounder with respect to differences in males’ and females’ injury risk, rather than sex alone. Mitigation to reduce this risk should, therefore, focus upon physical training, complemented by healthy lifestyle interventions

Characterization of pre-transplant psychosocial burden in an integrated national islet transplant programme

The psychological burden experienced by people with diabetes prior to islet transplantation is recognized but has not been studied comprehensively, especially in relation to glycemia. Therefore, we conducted a rigorous pre-operative psychosocial profile of UK islet transplant recipients, and compared groups with higher/lower HbA1 c to test the null hypothesis that pre-transplant hypoglycemia awareness and psychosocial burden would not be related to baseline HbA1 c in this high-risk cohort. Pre-transplant, recipients (n = 44) completed validated hypoglycemia awareness questionnaires and generic/diabetes-specific measures of psychological traits and states. Scores were compared in groups, dichotomized by HbA1 c (≤8% versus >8%). Participants were aged (mean±SD) 53 ± 10 years; 64% were women; with HbA1 c 8.3 ± 1.7%. Median rate of severe hypoglycemia over the preceding 12 months was 13 events/person-year and 90% had impaired awareness of hypoglycemia (Gold/Clarke score ≥4). Participants had elevated fear of hypoglycemia (HFS-II Worry), impaired diabetes-specific quality of life (DQoL) and low generic health status (SF-36; EQ-5D). One quarter reported scores indicating likely anxiety/depression (HAD). Dispositional optimism (LOT-R) and generalized self-efficacy (GSE) were within published ‘norms.’ Despite negative perceptions of diabetes (including low personal control), participants were confident that islet transplantation would help (BIPQ). Hypoglycemia awareness and psychosocial profile were comparable in lower (n = 24) and higher (n = 20) HbA1 c groups. Islet transplant candidates report sub-optimal generic psychological states (anxiety/depressive symptoms), health status and diabetes-specific psychological states (fear of hypoglycemia, diabetes-specific quality of life). While their generic psychological traits (optimism, self-efficacy) are comparable with the general population, they are highly optimistic about forthcoming transplant. HbA1 c is not a proxy measure of psychosocial burden, which requires the use of validated questionnaires to systematically identify those who may benefit most from psychological assessment and support

The impact of islet mass, number of transplants, and time between transplants on graft function in a national islet transplant program

The UK islet allotransplant program is nationally funded to deliver one or two transplants over 12 months to individuals with type 1 diabetes and recurrent severe hypoglycemia. Analyses were undertaken 10 years after program inception to evaluate associations between transplanted mass; single versus two transplants; time between two transplants and graft survival (stimulated C-peptide >50 pmol/L) and function. In total, 84 islet transplant recipients were studied. Uninterrupted graft survival over 12 months was attained in 23 (68%) single and 47 (94%) (p =.002) two transplant recipients (separated by [median (IQR)] 6 (3–8) months). 64% recipients of one or two transplants with uninterrupted function at 12 months sustained graft function at 6 years. Total transplanted mass was associated with Mixed Meal Tolerance Test stimulated C-peptide at 12 months (p <.01). Despite 1.9-fold greater transplanted mass in recipients of two versus one islet infusion (12 218 [9291–15 417] vs. 6442 [5156–7639] IEQ/kg; p <.0001), stimulated C-peptide was not significantly higher. Shorter time between transplants was associated with greater insulin dose reduction at 12 months (beta −0.35; p =.02). Graft survival over the first 12 months was greater in recipients of two versus one islet transplant in the UK program, although function at 1 and 6 years was comparable. Minimizing the interval between 2 islet infusions may maximize cumulative impact on graft function

Type 1 diabetes patients increase CXCR4+ and CXCR7+ haematopoietic and endothelial progenitor cells with exercise, but the response is attenuated

Background: Exercise mobilizes angiogenic cells, which stimulate vascular repair. However, limited research suggests exercise-induced increase of endothelial progenitor cell (EPCs) is completely lacking in type 1 diabetes (T1D). Clarification, along with investigating how T1D influences exercise-induced increases of other angiogenic cells (hematopoietic progenitor cells; HPCs) and cell surface expression of chemokine receptor 4 (CXCR4) and 7 (CXCR7), is needed. Methods: Thirty T1D patients and 30 matched non-diabetes controls completed 45 minutes of incline walking. Circulating HPCs (CD34+ , CD34+ CD45dim) and EPCs (CD34+ VEGFR2+ , CD34+CD45dimVEGFR2+ ), and subsequent expression of CXCR4 and CXCR7, were enumerated by flow cytometry at rest and post-exercise. Results: Counts of HPCs, EPCs and expression of CXCR4 and CXCR7 were significantly lower at rest in the T1D group. In both groups, exercise increased circulating angiogenic cells. However, increases was largely attenuated in the T1D group, up to 55% lower, with CD34+ (331±437 Δcells/mL vs 734±876 Δcells/mL p=0.048), CD34+VEGFR2+ (171±342 Δcells/mL vs 303±267 Δcells/mL, p=0.006) and CD34+ VEGFR2+CXCR4+ (126±242 Δcells/mL vs 218±217 Δcells/mL, p=0.040) significantly lower. Conclusion: Exercise-induced increases of angiogenic cells is possible in T1D patients, albeit attenuated compared to controls. Decreased mobilization likely results in reduced migration to, and repair of, vascular damage, potentially limiting the cardiovascular benefits of exercise. Trial registration: ISRCTN6373920

Applying a whole systems approach to improve the health behaviours of Royal Naval personnel

The Royal Navy (RN) is not immune to the global obesity epidemic. This poses considerable health, economic and occupational risks, and in due course will impact on operational capability; thus counteracting action needs to be taken. Due to the complex and multifaceted determinants of obesity, recent government guidance directs that obesity should be tackled at a community level using a whole systems approach (WSA). This thesis presents a programme of research that aimed to evaluate whether a WSA could be taken to create a healthier environment onboard a RN ship, which facilitates RN personnel to adopt or maintain prudent health behaviours, and whether such an approach could reduce the prevalence of obesity amongst personnel. Six studies were undertaken to confirm the need for, inform the development and implementation of, and to rigorously evaluate a healthy lifestyle intervention. The studies confirmed that there was a need for a healthy lifestyle intervention. A cross-sectional study of 600 RN personnel indicated that 29% were classified as being at any risk of obesity related ill health. Furthermore, personnel were typically consuming unhealthy diets and 13% of personnel were not being active enough to stay healthy. Moreover, a cross-sectional study undertaken onboard eight RN vessels indicated that although the physical activity environment supported healthy choices, the nutrition environment did not. The studies suggested that the intervention should take a multi-component, multi-level WSA. The evaluation of the intervention highlighted that a WSA can be applied to successfully improve the healthiness of the nutrition and physical activity environment onboard a RN ship. Strong leadership buy-in across all levels of the system, community involvement and sufficient financial support and resource were essential components contributing to intervention feasibility and sustainability. The research provides originality and presents recommendations to support the future delivery of WSA in a military context. The recommendations are also relevant to other non-military institutional settings

Environmental interventions to promote healthier eating and physical activity behaviours in institutions: A systematic review

Objective: The present review evaluated the effectiveness of environmental-based interventions aimed at improving the dietary and physical activity behaviours and body composition indices of adults in institutions.Design: A systematic review was conducted. Electronic databases (MEDLINE,Embase, PsycINFO, CINAHL, The Cochrane Library, Web of Science, ProQuestDissertation and Theses, Scopus and Athena) were searched for relevant articlespublished between database inception and October 2017. Searching, selecting and reporting were undertaken according to the Preferred Reporting Items forSystematic Reviews and Meta-Analyses (PRISMA) statement.Setting: Military establishments and maritime workplaces.Participants: Adults in institutions, aged 18–45 years.Results: A total of 27 842 articles were screened for eligibility, nine studies(reported in eleven articles) were included in the review. Five studies usedmultilevel strategies and four used environmental strategies only. Duration offollow-up ranged from 3 weeks to 10 years. Eight of the studies reportedsignificant positive effects on dietary behaviours, but effect sizes varied. The study that targeted physical activity had no effect on activity levels but did have a significant positive effect on physical fitness. No evidence was identified that the studies resulted in improvements in body composition indices.Conclusions: The evidence base appears to be in favour of implementingenvironmental interventions in institutions to improve the dietary behaviours ofadults. However, due to the small number of studies included in the review, andthe variable methodological quality of the studies and intervention reporting,further well-designed evaluation studies are required

Impact of the occupational environment of a submerged submarine on cardiometabolic health of Royal Navy submariners

Objective: To determine the effect of prolonged exposure to a submarine environment on biomarkers of cardiometabolic risk in Royal Navy (RN) submariners