Sleep Disturbances and Glucose Metabolism in Older Adults: The Cardiovascular Health Study.

ObjectiveWe examined the associations of symptoms of sleep-disordered breathing (SDB), which was defined as loud snoring, stopping breathing for a while during sleep, and daytime sleepiness, and insomnia with glucose metabolism and incident type 2 diabetes in older adults.Research design and methodsBetween 1989 and 1993, the Cardiovascular Health Study recruited 5,888 participants ≥65 years of age from four U.S. communities. Participants reported SDB and insomnia symptoms yearly through 1989-1994. In 1989-1990, participants underwent an oral glucose tolerance test, from which insulin secretion and insulin sensitivity were estimated. Fasting glucose levels were measured in 1989-1990 and again in 1992-1993, 1994-1995, 1996-1997, and 1998-1999, and medication use was ascertained yearly. We determined the cross-sectional associations of sleep symptoms with fasting glucose levels, 2-h glucose levels, insulin sensitivity, and insulin secretion using generalized estimated equations and linear regression models. We determined the associations of updated and averaged sleep symptoms with incident diabetes in Cox proportional hazards models. We adjusted for sociodemographics, lifestyle factors, and medical history.ResultsObserved apnea, snoring, and daytime sleepiness were associated with higher fasting glucose levels, higher 2-h glucose levels, lower insulin sensitivity, and higher insulin secretion. The risk of the development of type 2 diabetes was positively associated with observed apnea (hazard ratio [HR] 1.84 [95% CI 1.19-2.86]), snoring (HR 1.27 [95% CI 0.95-1.71]), and daytime sleepiness (HR 1.54 [95% CI 1.13-2.12]). In contrast, we did not find consistent associations between insomnia symptoms and glucose metabolism or incident type 2 diabetes.ConclusionsEasily collected symptoms of SDB are strongly associated with insulin resistance and the incidence of type 2 diabetes in older adults. Monitoring glucose metabolism in such patients may prove useful in identifying candidates for lifestyle or pharmacological therapy. Further studies are needed to determine whether insomnia symptoms affect the risk of diabetes in younger adults

Body composition and body fat distribution are related to cardiac autonomic control in non-alcoholic fatty liver disease patients

BACKGROUND/OBJECTIVES: Heart rate recovery (HRR), a cardiac autonomic control marker, was shown to be related to body composition (BC), yet this was not tested in non-alcoholic fatty liver disease (NAFLD) patients. The aim of this study was to determine if, and to what extent, markers of BC and body fat (BF) distribution are related to cardiac autonomic control in NAFLD patients. SUBJECTS/METHODS: BC was assessed with dual-energy X-ray absorptiometry in 28 NAFLD patients (19 men, 51±13 years, and 9 women, 47±13 years). BF depots ratios were calculated to assess BF distribution. Subjects’ HRR was recorded 1 (HRR1) and 2 min (HRR2) immediately after a maximum graded exercise test. RESULTS: BC and BF distribution were related to HRR; particularly weight, trunk BF and trunk BF-to-appendicular BF ratio showed a negative relation with HRR1 (r 1⁄4 0.613, r 1⁄4 0.597 and r 1⁄4 0.547, respectively, Po0.01) and HRR2 (r 1⁄4 0.484, r 1⁄4 0.446, Po0.05, and r 1⁄4 0.590, Po0.01, respectively). Age seems to be related to both HRR1 and HRR2 except when controlled for BF distribution. The preferred model in multiple regression should include trunk BF-to-appendicular BF ratio and BF to predict HRR1 (r2 1⁄4 0.549; Po0.05), and trunk BF-to-appendicular BF ratio alone to predict HRR2 (r2 1⁄4 0.430; Po0.001). CONCLUSIONS: BC and BF distribution were related to HRR in NAFLD patients. Trunk BF-to-appendicular BF ratio was the best independent predictor of HRR and therefore may be best related to cardiovascular increased risk, and possibly act as a mediator in age-related cardiac autonomic control variation.info:eu-repo/semantics/publishedVersio

Collider Bias Is Only a Partial Explanation for the Obesity Paradox

Background: “Obesity paradox” refers to an association between obesity and reduced mortality (contrary to an expected increased mortality). A common explanation is collider stratification bias: unmeasured confounding induced by selection bias. Here, we test this supposition through a realistic generative model. Methods: We quantify the collider stratification bias in a selected population using counterfactual causal analysis. We illustrate the bias for a range of scenarios, describing associations between exposure (obesity), outcome (mortality), mediator (in this example, diabetes) and an unmeasured confounder. Results: Collider stratification leads to biased estimation of the causal effect of exposure on outcome. However, the bias is small relative to the causal relationships between the variables. Conclusions: Collider bias can be a partial explanation of the obesity paradox, but unlikely to be the main explanation for a reverse direction of an association to a true causal relationship. Alternative explanations of the obesity paradox should be explored. See Video Abstract at http://links.lww.com/EDE/B51

Independent associations of physical activity and cardiorespiratory fitness with metabolic risk factors in children: the European youth heart study

Udgivelsesdato: septemberAIMS/HYPOTHESIS: High levels of cardiorespiratory fitness (CRF) and physical activity (PA) are associated with a favourable metabolic risk profile. However, there has been no thorough exploration of the independent contributions of cardiorespiratory fitness and subcomponents of activity (total PA, time spent sedentary, and time spent in light, moderate and vigorous intensity PA) to metabolic risk factors in children and the relative importance of these factors. METHODS: We performed a population-based, cross-sectional study in 9- to 10- and 15- to 16-year-old boys and girls from three regions of Europe (n = 1709). We examined the independent associations of subcomponents of PA and CRF with metabolic risk factors (waist circumference, BP, fasting glucose, insulin, triacylglycerol and HDL-cholesterol levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardised values of the six subcomponents. RESULTS: CRF (standardised beta = -0.09, 95% CI -0.12, -0.06), total PA (standardised beta = -0.08, 95% CI -0.10, -0.05) and all other subcomponents of PA were significantly associated with clustered metabolic risk. After excluding waist circumference from the summary score and further adjustment for waist circumference as a confounding factor, the magnitude of the association between CRF and clustered metabolic risk was attenuated (standardised beta = -0.05, 95% CI -0.08, -0.02), whereas the association with total PA was unchanged (standardised beta = -0.08 95% CI -0.10, -0.05). CONCLUSIONS/INTERPRETATION: PA and CRF are separately and independently associated with individual and clustered metabolic risk factors in children. The association between CRF and clustered risk is partly mediated or confounded by adiposity, whereas the association between activity and clustered risk is independent of adiposity. Our results suggest that fitness and activity affect metabolic risk through different pathways

Association Between Sleep Quantity and Quality in Early Adulthood With Cognitive Function in Midlife.

BACKGROUND AND OBJECTIVE: Growing evidence supports an association between sleep quality and risk of dementia. However, little is known about whether objectively measured sleep duration and quality influence cognition in midlife, a period of importance for understanding the direction of the association between sleep and dementia. We examined the association between sleep duration and quality, measured when participants were in their mid-30s to late 40s, and midlife cognition assessed 11 years later among Black and White adults. METHODS: As part of the Coronary Artery Risk Development in Young Adults cohort study, sleep duration and quality were assessed objectively using wrist actigraphy and subjectively by Pittsburgh Sleep Quality Index (PSQI) at 2003-2005. During 2015-2016, we evaluated midlife cognition using the Digit Symbol Substitution Test (DSST), Stroop test, Rey Auditory Verbal Learning Test, Montreal Cognitive Assessment (MoCA), and Letter Fluency and Category Fluency tests. We used multivariable logistic regression to examine the association between sleep parameters and poor cognitive performance, which was defined as a score that was >1 SD below the mean score. RESULTS: The 526 participants (58% women and 44% Black) had a mean age of 40.1 ± 3.6 years at baseline, a mean sleep duration of 6.1 ± 1.1 hours, and mean sleep fragmentation index (calculated as the sum of the percentage of time spent moving and the percentage of immobile periods ≤1 minute) of 19.2 ± 8.1%, and 239 (45.6%) participants reported poor sleep as defined by a PSQI global score of >5. After adjustment for demographics, education, smoking, body mass index, depression, physical activity, hypertension, and diabetes, those in the highest vs lowest tertile of sleep fragmentation index had over twice the odds of having poor cognitive performance (>1 SD below the mean) on the DSST (odds ratio [OR] = 2.97; 95% CI 1.34-6.56), fluency (OR = 2.42; 95% CI 1.17-5.02), and MoCA test (OR = 2.29; 95% CI 1.06-4.94). The association between sleep fragmentation and cognitive performance did not differ by race or sex. Objective sleep duration or subjective sleep quality was not associated with cognition in midlife. DISCUSSION: Actigraphy-measured high sleep fragmentation rather than sleep duration was associated with worse cognition among middle-aged Black and White men and women. Sleep quality is important for cognitive health even as early as midlife

Survivors of intensive care with type 2 diabetes and the effect of shared care follow-up clinics: study protocol for the SWEET-AS randomised controlled feasibility study

Published online: 13 October 2016Background: Many patients who survive the intensive care unit (ICU) experience long-term complications such as peripheral neuropathy and nephropathy which represent a major source of morbidity and affect quality of life adversely. Similar pathophysiological processes occur frequently in ambulant patients with diabetes mellitus who have never been critically ill. Some 25 % of all adult ICU patients have diabetes, and it is plausible that ICU survivors with co-existing diabetes are at heightened risk of sequelae from their critical illness. ICU follow-up clinics are being progressively implemented based on the concept that interventions provided in these clinics will alleviate the burdens of survivorship. However, there is only limited information about their outcomes. The few existing studies have utilised the expertise of healthcare professionals primarily trained in intensive care and evaluated heterogenous cohorts. A shared care model with an intensivist- and diabetologist-led clinic for ICU survivors with type 2 diabetes represents a novel targeted approach that has not been evaluated previously. Prior to undertaking any definitive study, it is essential to establish the feasibility of this intervention. Methods: This will be a prospective, randomised, parallel, open-label feasibility study. Eligible patients will be approached before ICU discharge and randomised to the intervention (attending a shared care follow-up clinic 1 month after hospital discharge) or standard care. At each clinic visit, patients will be assessed independently by both an intensivist and a diabetologist who will provide screening and targeted interventions. Six months after discharge, all patients will be assessed by blinded assessors for glycated haemoglobin, peripheral neuropathy, cardiovascular autonomic neuropathy, nephropathy, quality of life, frailty, employment and healthcare utilisation. The primary outcome of this study will be the recruitment and retention at 6 months of all eligible patients. Discussion: This study will provide preliminary data about the potential effects of critical illness on chronic glucose metabolism, the prevalence of microvascular complications, and the impact on healthcare utilisation and quality of life in intensive care survivors with type 2 diabetes. If feasibility is established and point estimates are indicative of benefit, funding will be sought for a larger, multi-centre study. Trial registration: ANZCTR ACTRN12616000206426Yasmine Ali Abdelhamid, Liza Phillips, Michael Horowitz and Adam Dean

High-intensity interval training vs. moderate-intensity continuous training in the prevention/management of cardiovascular disease

Moderate-intensity continuous training (MICT) has long been considered the most effective exercise treatment modality for the prevention and management of cardiovascular disease, but more recently high-intensity interval training (HIIT) has emerged into the clinical environment has been viewed as a potential alternative to MICT in accruing such benefits. HIIT was initially found to induce significant improvements in numerous physiological and health-related indices, to a similar if not superior extent to MICT. Since then, many studies have attempted to explore the potential clinical utility of HIIT, relative to MICT, with respect to treating numerous cardiovascular conditions such as coronary artery disease, heart failure, stroke, and hypertension. Despite this, however, the efficacy of HIIT compared to MICT with respect to in reversing the specific symptoms and risk factors of these cardiovascular pathologies for improved health and wellbeing as well as reduced morbidity and mortality is not well understood. In addition, HIIT is often perceived as very strenuous, which could potentially render it unsafe for those at risk of or afflicted with cardiovascular disease, but these issues are also yet to be reviewed. Furthermore, the optimal HIIT protocol for each of the cardiovascular disease cohorts has not been established. Thus, the purpose of this review article is to (i) evaluate the efficacy of HIIT relative to MICT in the prevention and management of cardiovascular conditions, and (ii) explore any potential safety issues surrounding the suitability and/or tolerability of HIIT for patients with cardiovascular disease, as well as the potential optimal prescriptive variables of HIIT for application in the clinical environment

Management of type 2 diabetes: the current situation and key opportunities to improve care in the UK

In common with global trends, the number of individuals with type 2 diabetes in the UK is rising, driven largely by obesity. The increasing prevalence of younger individuals with type 2 diabetes is of particular concern because of the accelerated course of diabetes-related complications that is observed in this population. The importance of good glycaemic control in the prevention of microvascular complications of diabetes is widely accepted, and there is a growing body of evidence to support a benefit in the reduction of cardiovascular events in the long term. Despite the importance of maintaining a healthy weight for the prevention of type 2 diabetes, the results from trials of lifestyle intervention strategies to reduce body weight have been disappointing. New glucose-lowering agents offer some promise in this regard, offering an opportunity to combat the dual burden of hyperglycaemia and obesity simultaneously. The timing and appropriate choice of glucose-lowering therapy has never been more complex as a result of rising prevalence of obesity in the young, concomitant obesity in some 90% of adults with type 2 diabetes and an ever-increasing range of therapeutic options. The present review evaluates performance measures specific to weight and glycaemic control in type 2 diabetes in the UK using data from the Quality and Outcomes Framework in England and Wales, and the Scottish Diabetes Survey. Potential barriers to improvement in standards of care for people with type 2 diabetes are considered, including patient factors, clinical inertia and the difficulties in translating therapeutic guidelines into everyday clinical practice