Short-term effectiveness of nutrition therapy to treat type 2 diabetes in low-income and middle-income countries: systematic review and meta-analysis of randomised controlled trials

OBJECTIVES: This review examined the evidence arising from randomised controlled trials regarding the impact of nutrition therapy on glycaemic control in people living with type 2 diabetes mellitus (T2DM) in low/middle-income countries (LMICs). DESIGN: Systematic review and meta-analysis using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Approach. DATA SOURCES: MEDLINE, EMBASE, Web of Science, OpenGrey and the International Clinical Trials Registry were searched (up to July 3 2020). ELIGIBILITY CRITERIA: Trials were included if they evaluated nutrition therapy in adults diagnosed with T2DM, were conducted in LMICs, measured glycaemic control and the trial included a 3-month post-intervention assessment. Nutrition therapy was defined according to American Diabetes Association recommendations. DATA EXTRACTION AND SYNTHESIS: Two independent reviewers screened the database. Study characteristics and outcome data were extracted using a data collection form. Meta-analyses were conducted for glycated haemoglobin (HbA1c) and fasting blood glucose. Trials were assessed for risk of bias (Cochrane Risk-of-Bias, Version 2.0) and overall certainty of evidence (GRADE). RESULTS: Four trials met inclusion criteria (total n=463), conducted in Malaysia, Iran and South Africa. All trials focused on nutrition education with no direct prescription or manipulation of diet. Mean differences between intervention and standard care were −0.63% (95% CI −1.47% to 0.21%) for HbA1c and −13.63 mg/dL (95% CI −37.61 to 10.34) for fasting blood glucose in favour of the intervention. Given the small number of eligible trials, moderate to high risk of publication bias and serious concerns regarding consistency and precision of the evidence, certainty of evidence was deemed to be very low. CONCLUSIONS: There is a lack of well-conducted randomised controlled trials that examine the long-term impact of nutrition therapy in LMICs, preventing firm conclusions to be made on their effectiveness. Further research is essential to discover realistic, evidence-based solutions. PROSPERO REGISTRATION NUMBER: CRD42020188435

Health benefits of electrically-assisted cycling:a systematic review

Abstract Background Electrically assisted bicycles (e-bikes) have been highlighted as a method of active travel that could overcome some of the commonly reported barriers to cycle commuting. The objective of this systematic review was to assess the health benefits associated with e-cycling. Method A systematic literature review of studies examining physical activity, cardiorespiratory, metabolic and psychological outcomes associated with e-cycling. Where possible these outcomes were compared to those from conventional cycling and walking. Seven electronic databases, clinical trial registers, grey literature and reference lists were searched up to November 2017. Hand searching occurred until June 2018. Experimental or observational studies examining the impact of e-cycling on physical activity and/or health outcomes of interest were included. E-bikes used must have pedals and require pedalling for electric assistance to be provided. Results Seventeen studies (11 acute experiments, 6 longitudinal interventions) were identified involving a total of 300 participants. There was moderate evidence that e-cycling provided physical activity of at least moderate intensity, which was lower than the intensity elicited during conventional cycling, but higher than that during walking. There was also moderate evidence that e-cycling can improve cardiorespiratory fitness in physically inactive individuals. Evidence of the impact of e-cycling on metabolic and psychological health outcomes was inconclusive. Longitudinal evidence was compromised by weak study design and quality. Conclusion E-cycling can contribute to meeting physical activity recommendations and increasing physical fitness. As such, e-bikes offer a potential alternative to conventional cycling. Future research should examine the long-term health impacts of e-cycling using rigorous research designs

Physical activity and sleep in extreme weight conditions

There is an increasing worldwide prevalence of obesity and anorexia nervosa. These conditions are having important health consequences. Among the numerous factors linked to these extreme weight conditions, deviations in physical activity and sleep patterns have been identified. However, the underlying mechanisms are not yet clear. Compared to healthy-weight individuals, those with obesity and anorexia nervosa present a distinctive temperament and cognitive profile as well as specific alterations in plasma endocannabinoid and endocrine hormone levels. Separately, these psychobiological processes are being associated with sleep-wake behaviour. This thesis gathers six studies to examine sleep and physical activity patterns in extreme weight conditions and the modulating role of several neuroendocrine factors, temperament, psychopathological indexes and cognitive functioning. A further aim, exclusive to anorexia nervosa, was to evaluate the effects of these mechanisms on the outcome of a partial, day hospital treatment. An inverse association was found between moderate-to-vigorous physical activity (MVPA) and body mass index, in part mediated via the actions of exercise on endocannabinoid system functioning. A temperament profile of low novelty seeking and high harm avoidance, as was in the participants with obesity, may be implicated in the adversity of these individuals towards exercise. Additionally, individuals with obesity were found to have difficulties in decision-making (selecting choices that provided immediate reward despite long-term loss), which was linked to both elevated plasma concentrations of irisin and less MVPA. Contrarily, a large variation was identified in the physical activity patterns of patients with anorexia nervosa; the majority presented daytime physical activity and MVPA habits that are similar to those of individuals without an eating disorder, except for a group who were particularly active. Furthermore, regulated and supervised MVPA may be a useful strategy for reducing the symptoms of depression identified in these patients and to promote treatment success. Regarding sleep, both individuals with obesity and anorexia nervosa reported several sleep difficulties, suggesting a u-shaped relationship between sleep and body mass index. Poor sleep quality was associated with increased plasma orexin-A in both conditions. In obesity the interaction between poor sleep and raised plasma orexin-A was associated with elevated body mass index. The interplay between sleep and orexin-A may have an adverse effect on treatment outcome. In conclusion, the present thesis demonstrates that both physical activity and sleep are highly relevant components in the psychopathology of obesity and anorexia nervosa, contributing to the development and maintenance of these conditions via their interaction with other altered psychobiological processes.En las últimas décadas se ha observado un rápido aumento en la prevalencia de la obesidad y anorexia nerviosa. Entre los factores asociados a estas condiciones extremas de peso, se han identificado alteraciones en la actividad física y la calidad del sueño. La presente tesis explora estos parametros en personas con obesidad y anorexia nerviosa, y como están asociados a procesos neuroendocrinologicos, a la personalidad, a índices de psicopatología, y al funcionamiento cognitivo. En segundo lugar se evalúan los efectos de la actividad física y el sueño en el resultado de una intervención de hospital de día para la anorexia nerviosa. Se encontró una asociación inversa entre la actividad de tipo moderada-alta y el índice de masa corporal, parcialmente mediada por los efectos del ejercicio sobre el sistema endocannabinoide. Un perfil de personalidad de baja busqueda de la novedad y alta evitación al daño, como se observó en los participantes con obesidad, podría estar implicado en la aversión que estos pueden presentar hacia el ejercicio. Asimismo, estos individuos demostraron dificultades en la toma de decisiones, vinculadas con elevadas concentraciones sanguineas de irisina y menor actividad. Contrariamente, una gran variación fue identificada en la actividad física de los pacientes con anorexia nerviosa; la mayoría presentaron hábitos de actividad similares a los de los individuos sin trastorno alimentario, aunque un subgrupo de pacientes era particularmente activo. Introducir una actividad física regulada seria útil para reducir los sintomas de depresión y facilitar el éxito del tratamiento. Por otro lado, las personas con obesidad o anorexia nerviosa indicaron tener dificultades en el sueño, lo que sugiere una relación a “u” entre el sueño y el índice de masa corporal. Una baja calidad de sueño estaba asociada a elevados niveles sanguineos de orexina-A. En la obesidad, esta interacción estaba relacionada con un más alto índice de masa corporal, mientras que en la anorexia nerviosa parece obstacular la eficacia de un tratamiento de hospital de día. En conclusión, la presente tesis demuestra que la actividad física y el sueño son variables importantes en la psicopatología de la obesidad y de la anorexia nerviosa que, alterados, pueden promover estas enfermedades interactuando con otros procesos psicobiológicos

Preference for high-carbohydrate foods does not change for children and adolescents in insulin-induced hypoglycemia

INTRODUCTION: Hypoglycemia elicits coordinated counter-regulatory neuroendocrine responses. The extent to which this process involves an increased drive to eat, together with greater preference for foods high in carbohydrate content, is unclear. Our objective was to examine this effect in children and adolescents (age 5–19 years) without diabetes and no prior known experience of hypoglycemic episodes. RESEARCH DESIGN AND METHODS: We administered a computerised task designed to examine preference for high-carbohydrate foods (sweet and savory) to pediatric patients (n=26) undergoing an insulin tolerance test as part of the routine clinical assessment of pituitary hormone secretory capacity. The task was completed at baseline and three time points after intravenous infusion of insulin (approximately 7, 20 and 90 min). RESULTS: Although all patients reached insulin-induced hypoglycemia (mean venous glucose at nadir=1.9 mmol/L), there was moderate evidence of no effect on preference for high-carbohydrate foods (moderate evidence for the null hypothesis) compared with euglycemia. Patients also did not display an increase in selection of foods of high compared with low energy density. Sensitivity of the task was demonstrated by decreased preference for sweet, high-carbohydrate foods after consumption of sweet food and drink. CONCLUSIONS: Results support the view that acute hypoglycemia does not automatically prompt the choice of high-carbohydrate foods for rapid glucose restoration, and further stresses the importance that people and families with children vulnerable to hypoglycemic episodes ensure that ‘rapidly absorbed glucose rescue therapy’ is always available