Clinical Research Directory

Investigating the Impact of Obesity on Pubertal Development in Girls

Background: Studies suggest that overweight girls may be developing breast tissue, and therefore starting puberty, earlier than normal weight girls. However, it is hard to distinguish breast tissue from fatty tissue. Researchers think that by using breast ultrasound, among other tests, they can do a better job of telling whether an overweight girl has breast tissue. This will help them understand if overweight girls are truly entering puberty before normal weight girls. Objective: To find out if overweight girls go through puberty earlier than normal weight girls. Eligibility: Healthy girls 8-14 years old who: * Are normal weight or overweight * Have some breast development * Have not started their first period Design: Parents of participants will be screened over the phone. Most participants will have 1 visit. However, they can choose to have multiple visits within 4 weeks. The visit will include: * Physical exam that includes examination of the breasts and genital area * Breast ultrasound: A small hand-held device will be passed back and forth over the chest. It uses sound waves to create a picture of the breast tissue. * Pelvic ultrasound: A small, handheld device will be passed back and forth over the lower belly. It uses sound waves to create a picture of the ovaries. * Urine and blood test * A special x-ray called a DXA to measure the amount of fat in the body: The participant will lie still on a table while the x-ray takes pictures of the body. X-ray of the hand: The picture will tell researchers how mature the participant s bones are. Participants may be asked to come back 6 months later to repeat these tests. ...

A Natural History of Genetic and Environmental Predictors of Pubertal Timing Among Youth With Obesity

Background: Obesity affects 1 in 5 children in the United States. Childhood obesity often persists into adolescence and adulthood. It can also raise the risk of sleep apnea, fatty liver disease, and fluid buildup in the brain and lead to early-onset puberty. This natural history study will explore how factors such as genes, hormones, diet, and chemical exposures affect puberty in children with obesity. Objective: To learn which factors predict the early start of puberty in children with obesity vs those of normal weight. Eligibility: Children aged 5 to 7 years with obesity or of normal weight. Design: Participants will have clinic visits every 6 months until they reach age 12. Each clinic visit will include these tests and procedures: A physical exam. Collection of blood, urine, and saliva samples. Some samples will be used for genetic tests. Questions about medical history and medications and supplements. A questionnaire about their physical activity over the previous week. A silicone wrist band. Participants will wear a soft wristband for a week prior to each visit. It will tell researchers what chemicals the children were exposed to during that time. Breast ultrasound, for girls. A gel will be applied, and a wand will be pressed against the skin. The wand uses sound waves to see the tissue inside the breast. DXA whole body scan. Once a year, participants will have a DXA (dual energy X-ray absorptiometry) scan. This scan measures the amount of bone, muscle, and fat in the body. Optional food diary. Parents may record everything the participant eats for two 24-hour periods ...

A Phase 2b Study to Examine the Safety and Efficacy of Once-Weekly MET097 in Adults With Obesity or Overweight

This study is designed to test how well MET097, an active drug, works to treat individuals with obesity or overweight when compared to placebo. MET097 or placebo will be given to individuals weekly for 28 weeks. If an individual is assigned to MET097 they will receive one of four different dose levels. Participants who have completed the first 28 weeks may participate in an exploratory extension study.

The Effects of Increasing Caloric Intake on Diet-Induced Thermogenesis and 24h Energy Expenditure

Background: Diet-induced thermogenesis (DIT) is the amount of energy one's body uses to eat food, absorb the nutrients from the food, and process those nutrients. Researchers would like to understand more about how changing the balances of protein, fat, carbohydrates, and total calories in the diet can affect DIT. Objective: To learn how different diets can change a person's DIT. Eligibility: Healthy people aged 18 to 60 years who have not intentionally lost weight in the past 6 months. Design: Participants will stay in a clinic for about 35 days. They will eat only the food provided. They will receive 8 different diets during the study, including 7 test diets. Participants will undergo multiple tests. They will be screened with blood and urine tests and a test of their heart function. During the first few days: Their waist, thigh, and neck circumference will be measured. They will have a DXA scan: They will lie on a padded table for about 20 minutes while an instrument measures the amount of fat in their body. They will be tested for diabetes. They will answer questionnaires about topics including eating behavior, hunger, and stress. Throughout the study: Their weight will be measured daily. Blood tests will be repeated. They will stay in a metabolic chamber a total of 9 times. They will remain in a closed room for 24 hours while researchers monitor the room temperature and levels of oxygen and carbon dioxide. Participants will collect all their urine for each 24-hour period. ...

Heart Health Study in Washington D.C. to Develop a Community-Based Behavioral Weight Loss Intervention

Background: \- Past studies suggest that the best way to improve heart health in the Black community is through community-based programs. Researchers will partner with DC community leaders. They will collect information about the health and health needs of people in mostly Black churches in DC. They will study things that affect heart health, like diabetes, blood pressure, cholesterol, and weight. They will also study how technology can keep track of activities and health. The information will show the health needs of church-based communities or faith-based organizations. Objectives: \- The primary objective of this study is to estimate the percentage of the population that meet ideal, intermediate, and poor criteria for each of the cardiovascular health factors (BMI, physical activity, dietary intake, blood pressure, total cholesterol, fasting plasma glucose, and cigarette smoking) in churches or faith-based organizations in the DMV area. This data will inform the design and implementation of a behavioral weight-loss intervention within the faith-based community immediately following this study. The secondary objectives are to: 1) evaluate usage of handheld devices for objectively measuring physical activity and dietary intake; 2) evaluate usage of web-based technology for monitoring cardiovascular health markers, including dietary intake; 3) examine referral methods for untreated hypertension, diabetes, and hypercholesterolemia; 4) compare lifestyle behaviors across levels of psychosocial factors, cultural norms, and neighborhood environment factors; and 5) formalize a community advisory board involved in the implementation of the health screening and needs assessment program and a future behavioral weight-loss intervention. Eligibility: \- Adults ages 19 to 85 who attend one of the study churches. Design: * Participants will visit their church for a 4-hour health exam. They will have their blood pressure and body measurements taken. They will have a drop of blood taken from their finger with a small needle. This blood will be tested for blood sugar and cholesterol. Participants will be given the results of these tests. * Participants will answer questions about their health. * All participants will be given an activity monitor to wear for 1 month. The activity monitor is worn around the wrist. Some participants will also receive an activity monitor that is worn around the waist. Participants will be given instructions on how to wear the activity monitors and follow the results on a website. * At the end of 1 month, participants will return one device (they can keep the other). They may receive a gift card for completing the study.

Effects of Brain Stimulation on Food Intake and Behavioral Weight Loss Treatment

This study will determine whether electrical stimulation of an area of the brain called the dorsolateral prefrontal cortex, which is important in determining the feeling of fullness after eating, affects how much food a person eats and weight loss over 4 weeks. It will also compare weight changes in people who attend weight loss counseling sessions and those who do not over this period of time. Obese, non-diabetic people between 18 and 60 years of age who are in good health and who live in the Phoenix, AZ, metropolitan area are eligible for this study. Candidates must have a body mass index of 35 kg/m(2) or more and weigh less than 350 pounds. Participants are admitted to the NIH inpatient unit in Phoenix for the first 9 days of the study for tests, which include meal tests to determine eating behaviors and caloric intake, blood and urine tests, glucose tolerance test, weight measurement, psychological assessments and DEXA scan to measure body fat. For 3 of the days, they will be asked to eat all of their food from automated vending machines. Some subjects receive transcranial direct current stimulation (TDCS). For this procedure, electrodes that conduct electricity are placed on the head and arm and the current is turned on for 40 minutes. Some tingling may be felt under the electrodes. Other subjects receive sham TDCS, with the current turned on only very briefly. After the evaluations, subjects are discharged home from the NIH unit and instructed to eat 25 percent fewer calories than they consumed while on a weight maintenance diet the first 3 days of their inpatient stay. They maintain the lower calorie diet at home for 4 weeks. During this period they come to the NIH unit 3 days a week to receive either real or sham TDCS. ...

A Study of XW003 in Obese Participants With Obstructive Sleep Apnea But Not Receive Positive Airway Pressure Therapy

The aim of the study is to assess the efficacy and safety of XW003 injections in obese participants with OSA but not receiving PAP

Characterization of Patients With Uncommon Presentations and/or Uncommon Diseases Associated With the Cardiovascular System

Background: \- Researchers are interested in studying individuals who have known or suspected metabolic, inflammatory or genetic diseases that may put them at a high risk for heart diseases or diseases of their blood vessels. Depending on the condition being studied, both affected and nonaffected individuals may be asked to provide blood and other samples and may undergo tests to evaluate the heart, blood vessels and lung function. The testing is tailored to the individual and/or condition being studied. Nonaffected individuals may include relatives of affected individuals and healthy nonrelated volunteers. Objectives: \- To study individuals who have or are at risk for cardiovascular diseases, and in some cases their unaffected relatives and healthy volunteers. Eligibility: \- Individuals between 1 and 100 years of age. Participants may be healthy volunteers, individuals with cardiovascular diseases, or unaffected relatives of individuals with cardiovascular diseases. Design: * Participants will have some or all of the following tests, as directed by the study researchers: * Photography of the face and full body * Body measurements * Radiography, including chest or limb x-rays * Metabolic stress testing to study heart and muscle function * Echocardiography to study heart function * Magnetic resonance imaging (MRI) studies, including cardiovascular MRI, angiography, and contrast MRI, to study heart function and performance * Computed tomography (CT) angiogram to obtain images of the heart and lungs * Positron emission tomography (PET) imaging to study possible fat infiltration of the heart * Six-minute walk test to study heart, lung, and muscle function and performance * Vascular ultrasound to study blood vessel walls * Blood, tissue, and other specimens will be collected for research and testing, and will be taken either as part of the clinical study or during surgical procedures. * Follow-up studies may be performed under separate research protocols.

Investigating the Use of Quercetin on Glucose Absorption in Obesity, and Obesity With Type 2 Diabetes

Quercetin is a compound naturally found in various foods. It may have some role in the treatment of obesity and diabetes. The purpose of this study is to investigate research volunteers with obesity or obesity with type 2 diabetes to determine whether quercetin affects the way glucose is absorbed by the body. Thirty two participants aged 19 to 65 who are considered to be medically obese or obese with type 2 diabetes will be enrolled in this study. Before the onset of treatment, they will undergo a medical history, physical exam, blood work, and urinalysis. During the study, participants will be given an oral glucose tolerance test three times; during these tests they will receive 1 or 2 grams of quercetin, or placebo. Researchers will collect blood samples and analyze the effect of the treatment on blood glucose.

Weight and Metabolic Management Study

The goal of this clinical trial is to learn whether elénzia CONTROL®, a nutritional supplement, can support weight management in adults who have either never used GLP-1 weight-loss medications or have recently stopped using them. The main question it aims to answer is: Does taking elénzia CONTROL® for 16 weeks help reduce body weight in adults who have never used GLP-1 medications or help prevent weight regain in adults who have recently stopped using them? The study will also look at changes in appetite, sugar cravings, mood, energy, diet, sleep, physical activity, stress, quality of life, and waist circumference. Researchers will compare elénzia CONTROL® with a placebo (a look-alike supplement that does not contain the active ingredients) to see whether elénzia CONTROL® has an effect on weight management. Participants will: Take two capsules of elénzia CONTROL® or placebo once a day, 30 minutes before their largest meal, for 16 weeks. Use a mobile app to record whether they have taken their capsules and complete study questionnaires and assessments. Measure and report their body weight and waist circumference throughout the study.

Tailoring Mobile Health Technology to Reduce Obesity and Improve Cardiovascular Health in Resource-Limited Neighborhood Environments

Background: Heart disease is a leading cause of death. People can reduce their heart disease risk by exercising more. Mobile health technology may make people more successful at increasing their exercise. This includes things like physical activity monitors and smartphone apps. Objective: To find out if mobile health technology can increase physical activity. Eligibility: African American women ages 21-75 who: * Are overweight or obese * Live in certain areas near Washington, DC * Have a smartphone that can use the study app Design: At visit 1, participants will * Answer survey questions. These may be about medical history, physical activity, and weight. They may also cover body image, health perception, and spirituality. * Have body size measured and get blood tests * Get a device to wear on the wrist. It will record physical activity and hours of sleep. * Learn how to download and use the study mobile app For 2 weeks, researchers will collect data about participants physical activity. Then participants will have a study visit with additional blood tests. All participants will get messages from the app that encourage exercise. Some participants will get data from the app about exercise near their home or work. Some participants may get face-to-face coaching. Participants may get wireless devices. These measure body weight, blood pressure, and blood glucose. Participants can measure these at home and upload the data to the app for the study. Participants will have visits after 3 and 6 months. They will repeat the visit 1 tests. ...

Evaluation of the Clinical Spectrum of Diabetes and Obesity in Youth and Adults

Background: Diabetes and obesity are chronic diseases. They can affect blood flow and how the body processes nutrients, and complications over time can lead to early death. Diabetes can affect children as well as adults, but the disease seems to be more severe and to progress faster when it appears in younger people. Researchers want to understand more about how diabetes and obesity develop and change over time. Objective: To collect data and samples regularly from people with obesity and diabetes. Eligibility: People aged 8 to 65 years. They must be overweight or obese; or have high blood sugar; or have problems with how their body uses food for energy. Design: Participants will have additional procedures during routine care visits at the NIH clinic. Data collected for the study will include the following: Information from the participant s medical chart will be kept for research. Questionnaires will ask about participant s eating habits, feelings, sleep, and substance use. They will take 30 to 60 minutes. Care providers will address any issues revealed in these surveys. Blood, saliva, urine, and stool samples will be collected. Samples may be used for genetic tests. Data and samples will be kept for future research. Participants may remain in the study up to 30 years.

A Study of XW003 in Obese Participants With Obstructive Sleep Apnea Receiving Positive Airway Pressure Therapy

The aim of the study is to assess the efficacy and safety of XW003 injections in obese participants with OSA receiving PAP

Vitamin E Pharmacokinetics and Biomarkers in Normal and Obese Women

Background: * Vitamin E is an antioxidant that reduces the damaging effects of oxygen in the body. Most American men (90%) and women (96%) do not get enough vitamin E from their diets; however, the amount of vitamin E needed by the body has been studied only in men, not women. In addition, it is unknown whether another antioxidant, vitamin C, helps vitamin E in protecting the body. Because vitamin E is a fat-soluble vitamin, how much body fat a person has could affect the amount of vitamin E needed for protection. Objectives: This study has three arms to examine vitamin E requirements: * To determine the amount of fat required to get the best vitamin E absorption from a meal. * To determine the amount (i.e., best dose) of vitamin E that must be consumed before it can be measured in the blood. * To examine how vitamin E and vitamin C work together in the body, in conjunction with diet and vitamin supplements. Eligibility: * Arms 1 and 2: Women between the ages of 18 and 40 years who have a normal weight and body mass index (BMI) of 27 or less. * Arm 3: Women between the ages of 18 and 40 years who have a normal weight (BMI 27), who are overweight (BMI \> 27), or who are overweight (BMI \> 27) and have non insulin-dependent diabetes. Design: * Arm 1: Five studies, each lasting 1 month with 1 month off between studies (total study = 10 months). Participants will take 500 1,000 mg of vitamin C twice daily for 2 weeks before admission to the clinical center for 1 week. * Study 1: Participants will eat breakfast containing a known amount of fat, after which they will take a vitamin E pill as well as receive an IV injection of vitamin E. Other foods contain only negligible amounts of vitamin E. Blood and urine samples will measure levels of vitamin E and other substances. * Studies 2 5: Outpatient visits will consist of the same tests as in Study 1; however, the amount of fat in the breakfast will range from 0% to 40% in random order. During one of the studies, an adipose tissue biopsy will be collected to determine how much vitamin E is in the tissues. * Arm 2: Five studies, each lasting 1 month with 1 month off between studies (total study = 10 months). Preparation for Arm 2 is the same as in Arm 1. The proportion of fat, muscle, and water in the body will also be measured. * Study 1: Participants will eat breakfast containing 30% fat, after which they will take a vitamin E pill as well as receive an IV injection of vitamin E. Conditions and procedures are the same as in Arm 1. * Studies 2 5: Outpatient visits will consist of the same tests as in Study 1; however, the amount of vitamin E in the breakfast will range from 2 to 30 mg in random order. * Arm 3: Outpatient (2 to 6 weeks) and inpatient studies (4 to 6 weeks). * Outpatient study: Participants will take 500 1,000 mg of vitamin C daily and provide blood and urine samples, as well as an adipose tissue sample. * Inpatient studies: Two vitamin E inpatient studies. Before these begin, participants vitamin C blood levels will be reduced by means of a diet low in vitamin C. Blood tests will determine how quickly vitamin C leaves the body. Once the vitamin C level is reduced, the first vitamin E study will begin. Study A: The procedure for this study is the same as in Arm 2, Study 1. Study B: The procedure for this study is the same as in Study A, except that the participants blood vitamin C levels will be higher.

Molecular and Clinical Profile of Diabetes Mellitus and Its Complications

Background: \- Family and twin studies have suggested that genetic factors influence approximately 50 percent of a person's susceptibility to type 2 diabetes. Recently, some of the genes involved in the development of type 2 diabetes have been identified, in large part by genome-wide association studies. Certain risk factors for type 2 diabetes, such as obesity and insulin resistance, are highly inheritable, as are diabetic complications such as diabetes-related eye and kidney disorders. However, few genes associated or linked with diabetes risk factors or complications have been conclusively identified, and more research is needed to study specific genetic factors associated with these aspects of diabetes. Objectives: \- To identify and characterize genetic variants associated with type 2 diabetes, its risk factors, and its complications. Eligibility: \- Individuals at least 18 years of age who are not pregnant or nursing mothers at the start of the study. Design: * All participants will provide information about family history, ethnicity and ethnic background, occupation, behavioral risk factors, and other data as requested by the researchers. * In addition to a general health history, participants will provide specific information about diabetes history, with particular emphasis on date of diagnosis, symptoms, initiation of insulin therapy, complications, and current medications. * Testing procedures will be different for individuals with and without diabetes. Those without diabetes will have an oral glucose tolerance test, while those with diabetes will be examined for diabetic complications. * Other tests during the study will include the following: * Physical examination with measurements of height and weight, waist circumference, blood pressure, and other tests for individuals who have been diagnosed with diabetes * Glucose tolerance test for those who have not been classified as having diabetes * Retinal photographs * Electrocardiograms * Hepatic Ultrasound * Blood and urine tests * Depending on the results of the examination and laboratory findings, participants may be asked to return to the clinic for supplemental interviews, physical examinations, or blood tests, or to arrange referrals for medical evaluation and treatment. * Participants who have diabetes will be asked to return for yearly follow-up visits. Participants who do not have diabetes at the initial examination will be asked to return for follow-up visits every 2 years.

HMB Plus Vitamin D to Preserve Muscle in Older Adults Starting Semaglutide

This randomized, double-blind, placebo-controlled trial will evaluate whether daily calcium beta-hydroxy-beta-methylbutyrate (calcium-HMB) plus vitamin D3 preserves muscle mass, physical function, and resting metabolism in adults aged 65 to 85 years with type 2 diabetes who are newly starting semaglutide as part of usual clinical care. Participants will receive calcium-HMB plus vitamin D3 or matching placebo for approximately 6 months. The primary outcome is change in appendicular lean mass measured by dual-energy X-ray absorptiometry from baseline to month 6. Secondary assessments include body composition, muscle strength, physical performance, gait, physical activity, resting metabolic rate, metabolic measures, and whole-body quantitative computed tomography. An optional mechanistic substudy of up to 36 participants will include D3-creatine dilution, nonradioactive stable isotope infusions, repeated blood sampling, a standardized meal, breath sampling, and vastus lateralis muscle biopsies at baseline and month 6.

Trial of the Combination of Alpha-Lipoic Acid and Mirabegron in Women and in Men With Obesity

Background: Obesity and related illnesses cause at least 2.8 million deaths each year worldwide. Few treatments exist for obesity that are safe and widely available. A study drug (mirabegron \[MG\]) combined with a supplement (alpha-lipoic acid \[ALA\]) may help. Objective: To learn how MG and ALA can help the body process food. Eligibility: People aged 18 to 65 years with a body mass index between 30 and 45 kg/m2. Design: Participants will be screened. They will have a physical exam. They will have blood and urine tests and a test of their heart function. They will speak with a dietician. The study has two phases. Each phase begins with a 2-day stay in the clinic; then the participant will take the study drugs at home for about 4 weeks, followed by another 2-day stay in the clinic. They will also have outpatient visits about 2 weeks after each clinic stay. During the clinic stays, participants will undergo many tests: They will have a plastic tube (catheter) inserted into a vein in each arm. These will be used to draw blood and to infuse glucose (sugar) and insulin. They will have imaging scans. They will have a clear hard plastic shield placed over their head to measure oxygen and carbon dioxide as they breathe. Participants will take the study drugs at home. Both MG and ALA are taken by mouth with water. During one phase, participants will take MG plus a placebo. A placebo looks like the study drug but doesn t contain medicine....

Diabetes and Heart Disease Risk in Blacks

It is unknown if obesity contributes to the development of heart disease in African American men and women. This study was created to determine whether there is a relationship between sex and body size and the incidence of heart disease in African American men and women. Researchers will attempt to associate obesity with the presence of heart disease risk factors. Risk factors that will be studied include; total body fat, body fat distribution, fat content of the blood (triglyceride concentration, low density lipoproteins \[LDL\], and high density lipoproteins \[HDL\]), how fast fat is removed from the blood, and how well insulin works in the body. Scientific studies have shown that obesity and increased levels of fat content in the blood are important risk factors for heart disease in Caucasian women. However, similar studies in African American women have failed to show the same correlation. In fact, it appears that African American women in all three body weight groupings, nonobese, overweight, and obese experience high death rates due to heart disease. In addition, prior research has shown that obese African American men tend to have elevated levels of fat in the blood while African American women have normal blood fat levels. Therefore, if high levels of triglycerides (fat found in the blood) are not seen in non-diabetic obese African American women, it cannot be considered a risk factor in this population. This suggests that studies conducted on Caucasian women may not provide insight into heart disease risk factors in African American women. The study will take 2000 healthy non-diabetic African American men and women (ages 18-70) and body mass index 3 subgroups; nonobese, overweight and obese. Diabetes undeniably increases the risk of heart disease. Therefore patients suffering from diabetes will not be included in the study. Candidates for the study will undergo a series of tests and examinations over 2 outpatient visits. Subjects will have body fat analyses, resting energy expenditure measurements, an EKG (electrocardiogram), and specific blood tests. Researchers believe this study will provide significant insight into the causes of obesity and heart disease in African Americans.

Water Deprivation Protocol

Background: \- One area in which obese and lean individuals may be different is how their bodies handle water balance and thirst. Studies done in animals suggest that individuals with greater body fat may tolerate periods without water better than lean animals. Other research has found a link between the ability to tolerate periods without water and increased body weight. Researchers are interested in studying whether the ability to tolerate periods without water and ability to feel thirst might differ in lean versus obese individuals. Objectives: \- To evaluate the effects of water deprivation and feelings of thirst in lean and obese individuals. Eligibility: \- Healthy individuals at least 18 years of age who are either lean (body mass index less than 26 kg/m(2)) or obese (body mass index at least 35 kg/m(2)). Design: * Participants will be screened with a medical history, physical examination, and blood and urine tests. * Participants will spend the entire study (13 days) as inpatients at the National Institutes of Health Clinical Center. * Participants will have the following tests and procedures: * Body composition assessment (using low-level x-rays) to determine the percentage of fat tissue in the body. * Oral glucose tolerance test (similar to that often used to diagnose diabetes). Individuals who are suspected to have diabetes will not be allowed to continue with the study. * High salt infusion test, in which an infusion of saline (salt water) will be given for 2 hours and participants will respond to questions about how hungry and thirsty they feel during the procedure. * Water deprivation test, in which participants will go for 24 hours without water or food and respond to questions about how hungry and thirsty they feel. * 24-hour stay in a metabolic chamber to determine how many calories participants burn in a day. * A series of questionnaires about participants' eating habits, feelings about food, and personal feelings, as well as computer-based tests involving the performance of various tasks. * Measurement of free-living energy using doubly-labeled water, in which participants will drink a sample of water with extra-heavy atoms of hydrogen and oxygen to evaluate the amount of water in the body. * 24-hour urine collection. * Frequent blood samples, urine collection, and fat tissue biopsies during the various study procedures. * After the end of the 13-day study, participants will return after 1 week for a final urine collection....

High-flow Nasal Oxygen Therapy in Obese Patients Undergoing Sedativegastrointestinal Endoscopy

Obese patients often have fat accumulation in the head and neck, increased soft tissue in the oropharynx, decreased lung compliance, decreased lung volume and residual volume, and some obese patients also suffer from obstructive sleep apnea. Therefore, obese patients may experience hypoxemia during sedative gastroscopy. High-flow nasal cannula oxygen therapy (HFNC) can provide patients with high-flow (20-70 L/min) and adjustable oxygen concentration (21%-100%) through a special nasal prong catheter. It has the function of warming and humidifying the air, relieving pressure on the nasal mucosa, maintaining airway patency and moisture, reducing the risk of nasal bleeding. In addition, HFNC can generate positive airway pressure (3-7 cmH2O), increase end-expiratory volume, help with alveolar recruitment, prevent atelectasis, and reduce shunts. The flow rate of HFNC is positively correlated with the nasopharyngeal pressure. At a flow rate of 50 L/min, the nasopharyngeal pressure can exceed 3 cmH2O. Obese patients are prone to upper airway obstruction under sedation or anesthesia. The use of HFNC at 70 L/min perioperatively can reduce hypoxemia in patients, but discomfort in the nasopharynx may occur at this flow rate. The optimal flow rate for clinical use of HFNC has not been established. Meta-analysis shows that when the oxygen flow rate during painless esophagogastroduodenoscopy is greater than 30 L/min, it can significantly reduce the incidence of hypoxemia in patients. Therefore, for obese patients undergoing painless esophagogastroduodenoscopy, the investigators propose using HFNC at three different flow rates: 30 L/min, 50 L/min, and 70 L/min, to provide guidance on the optimal flow rate for clinical use of HFNC.

Cross-Sectional and Longitudinal Studies of "Pre-Diabetes" in the Pima Indians

Insulin resistance and a defect in early insulin secretion are risk factors for the development of type 2 diabetes mellitus. A recent longitudinal analysis which tracked the development of diabetes demonstrated that both insulin action and early insulin secretion deteriorate as individuals progress from normal to impaired glucose tolerance and then to diabetes. These results suggest that both inherent (apparent in normal glucose tolerant subjects who progress to diabetes and likely to have a genetic basis) and acquired (evident as individuals progress from NGT to IGT to diabetes and possibly environmental in origin) defects in insulin action and secretion contribute to the pathogenesis of type 2 diabetes. To identify the genetic and environmental determinants of diabetes we are continuing to determine: (1) if there are genes that segregate with metabolic risk factors for diabetes which might therefore be genetic markers for type 2 diabetes and (2) the mechanisms mediating genetic and environmental determinants of insulin resistance and impaired insulin secretion. \<TAB\> Volunteers for this study will be admitted to the clinical research ward where they will undergo several tests to determine body composition, oral and intravenous glucose tolerance and in vivo insulin action. In addition, in selected subjects, adipose and/or skeletal muscle tissue will be obtained by percutaneous biopsy for in vitro studies of gene expression and insulin action in these tissues. A transformed lymphocyte cell line will be established for each subject as a permanent source of DNA for genetic studies. Genetic markers for type 2 diabetes and insulin resistance will be sought by typing each individual at positional and functional candidate loci in the hopes of finding an association between these loci and obesity, insulin secretion, insulin resistance and/or type 2 diabetes.

Predicting Weight Gain and Weight Loss Associated With Overeating or Fasting

This study will investigate how to better predict why some individuals gain or lose weight more easily than others. It will examine whether the increase in the amount of energy a body burns in 24 hours with overeating or the decrease over 24 hours with fasting can help determine how easily someone gains or loses weight. Healthy people between 18 and 60 years of age who have a body mass index (BMI) between 18.5 kg/m(2) and 24 kg/m(2) (for overfeeding study) or a BMI greater than 27 kg/m(2) with a body weight less than 350 pounds (weight loss study) may be eligible for this study. The study requires a 10-week admission to the NIH Clinical Center (2-week baseline, 6-week overfeeding/weight loss, 2-week post-weight change). Participants undergo the following tests and procedures during the hospital admission: * Medical history, physical examination and laboratory studies * Questionnaires to assess eating behavior, food preferences, body composition, and activity level * Body composition assessment (height, weight, waist circumference, and fat mass and muscle content through DXA and MRI scans) * Oral glucose tolerance test * Meal test to measure the response of certain hormones to food * Activity monitors to determine activity level * Metabolic chamber study to measure calories burned over 24 hours and monitor body temperature * Free-living energy use study to measure calories burned under normal home conditions over 7 days * Fat and muscle biopsies * Dietary intervention: Measurements of food intake and energy loss over a 6-week overfeeding (1.5 times the subject s normal food intake) or weight loss (one-half the subject s normal food intake) program Followup procedures after the inpatient stay: * Height and weight measurements at 6 months (overfeeding study participants) and monthly for the first year, at 3-month intervals for the second year, and then yearly for 3 more years (weight loss study participants) * Yearly visits (2-night inpatient stay) for all participants for repeat meal test, DXA, oral glucose tolerance test, behavioral questionnaires and, in women who can become pregnant, pregnancy test

PPDTM CorEvitasTM Obesity (OBR) Drug Effectiveness and Safety Registry

The design is an open-ended prospective observational (non-interventional) registry for subjects living with excess weight or obesity under the care of a qualified provider with documented experience treating patients with obesity

Inspiratory Muscle Strength Training in Adults With Obesity

The purpose of this study is to determine whether inspiratory muscle strength training reduces blood pressure in adults with obesity.