Clinical Research Directory

Effects of Acute Sleep Deprivation on Health

This study will investigate whether various types of regular exercise can provide protective effects against metabolic abnormalities induced by sleep restriction. It will examine responses related to metabolic health, cognitive function, energy expenditure, subjective feelings, and human behaviors, including physical activity and energy intake.

A Biological Atlas of Severe Obesity (Biological Tissue Collection)

Type 2 diabetes and obesity are both multifactorial diseases resulting from gene-environment interactions. However, this interaction, as well as the specific effect of each polymorphism, remains poorly understood. We now proposed a prospective cohort study to improve our understanding of the influence of phenotypic characteristics on gene expression in tissues involved in glucose and/or lipid metabolism by collecting different biological samples.

Ursodeoxycholic Acid Attenuates Statin-Induced Impaired Glucose Tolerance

The purpose of this clinical trial is to understand whether the drug Ursodeoxycholic acid (UDCA) can prevent glucose intolerance in participants with hyperlipidemia who are taking statins. It will also assess the safety of UDCA. The primary questions it aims to answer are: * Will UDCA reduce the incidence of glucose intolerance in participants taking oral statins? * Will the use of UDCA decrease other adverse events in patients taking oral statins? Participants will: * Take Atorvastatin combined with UDCA or a placebo daily for 6 months * Have follow-up visits on day 40, day 110, and day 180 Have their examination indicators recorded.

Ultra-processed Food Reducing Intervention and Continuous Glucose Monitoring

The goal of this trial is to investigate whether reduction in ultra-processed food intake through diet counseling and education can improve postprandial glucose levels and glycemic variability among Korean healthy adults aged 20-30 years. The main questions it aims to answer are: * Does the reduction in ultra-processed food intake lower postprandial glucose levels and glycemic variability in healthy adults without a history of diabetes? * Does the reduced intake in different ultra-processed food subgroups and items differentially influence postprandial glucose and glycemic variability? * Does other dietary and lifestyle factors (physical activity, sleep, smoking) alter the association between ultra-processed food intake reduction and glycemic variability? Participants will: * Undergo the 10-day pre-intervention monitoring period, during which each participant will wear a continuous glucose monitoring (CGM) device and concurrently report their daily dietary intakes (all food and beverage consumptions) and other lifestyle behaviors (sleep, smoking, physical activity) * After the 10-day pre-intervention monitoring period, participants will be randomized to either intervention or control group * Intervention group: Participants will visit the research site to receive dietitian-led nutrition education and personalized diet counseling targeting reduction of ultra-processed food intake, as well as improving diet quality. Personalized diet counseling will be provided by study dietitian based on participant's records of dietary intakes during the 10-day pre-intervention monitoring period. * Control group: Participants will receive dietitian-led nutrition education and personalized diet counseling targeting general improvement in nutrient intake (based on the national dietary guidelines). * After the intervention, participants will undergo the 10-day post-intervention monitoring period, during which participants will wear a new CGM device for an additional 10 days and continue daily reporting of dietary intakes (all food and beverage consumptions) and lifestyle behaviors (sleep, smoking, physical activity).

Signos DM2 Empowerment Study (SIGNOS-CGM-EMPOWER-201-2022)

The use of continuous glucose monitoring (CGM) in earlier data has inspired behavioral changes leading to improved adherence to an exercise plan in individuals and eating habits in people with diabetes. Mobile health (mHealth) platforms provide satisfactory, easy-to-use tools to help participants in the pursuit of weight change goals. We hypothesize that the use of CGM data and the Signos mHealth platform will assist with weight control in a population of people with type 2 diabetes mellitus who are not using insulin.

Use of Continuous Glucose Monitoring in Non-Diabetic Population to Compliment Signos Mobile Health Platform

Metabolic syndrome and resulting downstream health effects remains a growing health concern. In published trials, the use of continuous glucose monitoring (CGM) assists behavioral changes efforts, leading to improved adherence and results from diet and exercise changes in individuals with obesity, pre-diabetes and diabetes. Mobile health (mHealth) platforms provide satisfactory, easy-to-use tools that help participants in the pursuit of weight change goals. We hypothesize that the use of CGM data and targeted coaching and nutrition education will assist with weight optimization goals in the general (non-diabetic) population using the Signos mHealth platform, with associated health benefits.

Rare and Atypical Diabetes Network

RADIANT is a network of 14 clinical sites and several laboratories dedicated to the study of atypical diabetes. The objective of this study is to define new forms of diabetes and the unique mechanisms underlying these forms of atypical diabetes. The specific aims are to: 1. Identify and enroll individuals and families with undiagnosed rare and atypical forms of diabetes. 2. Determine the etiologic basis of the metabolic disorder among individuals and families with novel forms of rare and atypical diabetes. 3. Understand the pathophysiology of individuals and families with novel forms of rare and atypical forms of diabetes.

Hepcidin and Glucose Metabolism

Gestational diabetes mellitus (GDM), defined as hyperglycemia with blood glucose values above normal but below those diagnostic of DM, and iron deficiency (ID) with or without anemia (IDA) are common during pregnancy. Both disease patterns are associated with an increased risk of complications during pregnancy and at delivery and may have a variety of negative effects on different aspects of child development. Thus, GDM and ID/IDA during pregnancy should be prevented. Whether iron supplementation with high oral doses acutely increases hepcidin during pregnancy, and whether this acute iron-induced increase in hepcidin decreases insulin sensitivity, is uncertain.

The Impact of Overnight Nutrition Support on Sleep and Circadian Rhythm Disruption in the ICU

The purpose of this study is to determine whether modifying the timing of nutrition support from overnight to daytime enhances sleep quality, preserves circadian rhythms, and improves overall inflammation and cardiometabolic profiles in postoperative patients in the cardiac surgical ICU on enteral nutrition.

Effects of Tagatose on Glycemic Response and Gastrointestinal Microbiota in Healthy Adults

The primary objective of this clinical-trial is to determine, in subjects with impaired fasting glucose (IFG) and/or insulin resistance (IR), if tagatose meets the definition of a prebiotic, namely that consuming tagatose for 4 weeks selectively stimulates the selective growth of bacteria in the colon and is associated with a health benefit (oral glucose tolerance) when compared to consuming the control treatment (10g sucrose) for 4 weeks.

The Acute T-Rex (Timing of Resistance Exercise) Study

The primary aim of this study is to evaluate if a single bout of AM vs PM resistance exercise has different effects on insulin sensitivity and sleep. A randomized cross-over trial be used to compare resistance exercise at two different times of the day. Each condition will take place in a laboratory setting. Each condition will consist of exercise, overnight sleep, and oral glucose tolerance tests the following day. The AM exercise will occur \~1.5 hours after habitual wake, and PM exercise will occur \~11 hours after habitual wake. After a 2-6 week washout, participants will complete the other condition. The hypothesis is that PM exercise will be more beneficial than AM exercise in improving insulin sensitivity. This study could identify if there is a better time of day to perform resistance exercise to decrease risk of developing Type 2 Diabetes Mellitus.

Time to Move in Pregnancy Hyperglycemia

This randomized controlled crossover trial of 36 pregnant individuals with gestational diabetes (GDM) or gestational glucose intolerance (GGI) will: 1. Determine the effects of physical activity (PA) timing, specifically 30 minutes of moderate intensity walking or stepping in the morning (between 5am-9am, within 30-40 minutes of starting breakfast), versus late afternoon/evening (between 4pm-8pm, within 30-40 minutes of dinner) on glucose across the 24-hour cycle. 2. Explore the potential effects of the timing of PA on sleep and mood state.

Effect of a Low-carb Dietary Intervention in Obese Patients: a Pilot Trial

Effects of a 6 months low-carb dietary intervention on glycemic control, body composition and gut-brain interaction in obese and lean patients with and without glucose intolerance or diabetes

The Impact of Removal of Exercise on Glycemic Control and Vascular Health in Older Active Adults

The purpose of this study is to determine if an acute bout of removal of exercise reduces enothelial function and glycemic control in an active, older adult population; and whether a 3 day return to exercise restores this response. Glycemic control is the blood glucose response following the consumption of a meal. It is an indicator of insulin resistance (or type 2 diabetes) and impaired glycemic control has been suggested to lead to cardiovascular disease. Endothelial function has been shown to be improved by chronic or acute increases in physical activity. Both of these have been shown to be impaired to acute bouts of inactivity in young populations; however the impact of acute inactivity in older adults is less understood. In this proposal the investigators will examine 1)how quickly impairments in glycemic control occur to acute physical inactivity in older adults who exercise, 2) how quickly impairments in endothelial function occur to acute inactivity in older adults who exercise, and 3) whether 3 days of a return to exercise restores these responses.

Sleep and Metabolism

The goal of this study is to uncover sleep and circadian mechanisms contributing to adverse metabolic health. The protocol is a 21 day (7 outpatient days, 14 inpatient days) mechanistic randomized-crossover study designed to identify the impact of chronic sleep restriction and circadian timing, independently and in combination on energy metabolism and identify the independent and combined effects on glucose tolerance.

Dietary Strategies for Remission of Type 2 Diabetes

In this project, the investigators will perform a multicenter randomised controlled trial to determine whether advice to consume a moderate, whole food-based low-carbohydrate high-fat (LCHF) ad libitum diet (CarbCount program) can produce and maintain equal remission rates of type 2 diabetes (T2D) as a nutritionally complete very-low-calorie formula diet followed by a energy-restrictive (i.e., calorie counting) diet (DiRECT principles). Within the principles of each approach, the dietary goals and change will be adjusted according to individual needs/capabilities conducive to long-term adherence. Furthermore, the investigators aim to determine whether the rate of diet-induced remission is reflected in/can be predicted by baseline or diet-induced changes in glucose variability (e.g., time-in-range measured by continuous glucose monitoring) and other factors such as anthropometric changes and genetic susceptibility. Each center will also conduct locally-lead standalone mechanistic research, including analyses of intra-abdominal/hepatic fat accumulation, adipose tissue biopsies and/or measurements of energy metabolism. Additionally, changes in medication use, nutritional status, cardiovascular disease risk, as well as adverse events, will be monitored.

MAL-ED Metabolic: A Follow-Up of Chronic Disease at Puberty

The concept that the roots of cardiometabolic disease start in early life was established by Dr. David Barker, who documented relationships between low birthweight (as a marker for challenges during gestation) and later cardiovascular disease (CVD). Later work has suggested that post-natal challenges (similar to prenatal ones) may also exhibit links to later cardiometabolic disease, with the strongest links appearing to be between low weight in early childhood and later hypertension and high waist circumference (WC). However, assessments for the relationship between early childhood challenges and insulin resistance and glucose regulation have been lacking and long-term cohort studies are few. In this project, we aim to assess children initially followed as part of The Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health (MAL-ED) study, where they received frequent measures of anthropometry and laboratory assessments for intestinal pathogens. These children are now of peri-pubertal age--a time period associated with metabolic shifts. We will assess for glucose dysregulation and findings associated with the metabolic syndrome, and we will analyze potential associations between current chronic disease risk findings with early life poor growth and intestinal pathogen carriage rate. As such, we hope to uncover potential targets in early life health to reduce later chronic disease risk.