Clinical trials

54

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Condition / disease
Location
Status: Not yet recruiting

Discovering Determinants of Food Intake by Application of Artificial Intelligence to Complex, High-Dimensional Data

Background: Many people in the United States are overweight or obese. Researchers want to learn why some people can overeat and not gain weight, whereas others who do not overeat still gain weight. Objective: To study factors related to food intake that can lead to weight gain over time. Eligibility: Healthy adults aged 18 to 60 years. Design: Participants will have 6 to 8 clinic visits over 2 years. The first 3 or 4 study visits will be 1 week apart. Procedures during visits may include the following: Collection of blood, hair, urine, and stool samples. Measurement of the waist, neck, thighs, and other parts of the body. Dual energy x-ray absorption (DXA) scan: Participants will lie still on a padded table while they are scanned to measure body fat. Physical activity monitor: Participants will wear a monitor on the wrist for 2 weeks. Cognitive tests: Participants will perform tasks to measure attention, memory, and brain function. Continuous glucose monitor. Participants will wear a device that measures their blood glucose for 1 week. Mixed meal test and stomach emptying test. Participants will drink a breakfast shake and swallow a dose of acetaminophen. Blood will be drawn over the next 4 hours. Resting metabolic rate: Participants will wear a clear hood over their head while they rest for 20 minutes. The hood will measure the gases they breathe. Breakfast and lunch test. Participants will eat a standard breakfast. They will be allowed to select from foods and eat as much as they like at lunch. They will be asked how hungry or full they are. Questionnaires. Participants will answer questions about their health, sleep, physical activity, and eating.

Participants needed: 800
Trial details
Age: 18-60Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Stated willingness to comply with all study procedures and availability for the... [+2]

Weight >=204 kg (>=450 pounds, maximum weight of the iDXA machine as per manufac... [+4]

Status: Recruiting

Longitudinal Immunophenotyping of Patients With Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD) is a term used to describe disorders that cause long-term inflammation in the digestive tract. Symptoms include stomach pain, diarrhea, and bleeding. Crohn's disease and ulcerative colitis are the 2 main types of IBD. Researchers want to conduct a natural history study to learn more about whether genetic factors can cause IBD; how immune cells contribute to IBD; and how diet, drugs, and disease affect those cells. Objective: To better understand IBD over time. Eligibility: Adults aged 18 to 85 years with Crohn's disease, ulcerative colitis, or another IBD. Their healthy relatives are also needed. Design: Affected participants will have clinic visits every 6 months for 3 years. Once a year, they will have these procedures: A physical exam with blood and stool samples. Ultrasound of the abdomen. A wand will be rolled over the skin. It uses sound waves to capture images of the intestines. Magnetic resonance imaging (MRI) scan. They will lie on a table that slides into a tube. Magnetic fields will capture images of the intestines. Colonoscopy. A long, flexible tube with a video camera will be inserted into the rectum to view the entire colon. Up to 12 tissue samples may be taken. Upper endoscopy, for those with Crohn's disease. A long, thin tube with a camera will be inserted through the mouth and into the first part of the small intestine. Up to 12 small tissue samples may be taken. Questionnaires. Participants will answer questions about their disease and their diet. Midyear visits will include a physical exam, blood and stool collection, ultrasound, and questionnaires Healthy relatives will have 1 blood draw for genetic tests.

Participants needed: 100
Trial details
Age: 18-85Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Adults 18 - 85 years of age [+6]

Unable or unwilling to provide informed consent [+1]

Status: Not yet recruiting

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.

Participants needed: 1,000
Trial details
Age: 8-65Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Age 8 years to 65 years

History of significant medical illnesses that the investigators feel may interfe... [+2]

Status: Not yet recruiting

Effects of Meal Macronutrients on Postprandial Lipids

Background: Abnormal fats in the blood can lead to many problems, including heart disease. Researchers want to learn more about how eating meals with different levels of nutrients affects fats in the blood. Specifically, they want to study people with too much body fat, too little body fat, and a kidney problem called nephrotic syndrome. Objective: To learn more about how different types of foods affect fat levels in the blood. Eligibility: People aged 18 years or older with a health condition that affects how their body handles fats. Healthy volunteers are also needed. Design: Participants will have 2 overnight stays in the clinic within 6 months. At each visit, after staying overnight, they will eat a breakfast casserole. At 1 visit, breakfast will be a high-fat, low carbohydrate meal. At the other, it will be a high-carbohydrate, low-fat meal. Participants will have a tube inserted into a vein in their arm. They will have blood drawn via the tube 12 times in 8 hours: 2 times before they eat the breakfast and 10 times after. Participants will have other tests during their stays: * A resting metabolic test captures the air they exhale and measures how much energy they use at rest. * A dual energy X-ray absorptiometry (DXA) scan measures how much fat and muscle they have. * A Fibroscan is a special type of ultrasound of the liver. * A body surface scan uses lasers to measure the total area of the body. * A bioelectric impedance (BIS) exam measures how fast small electric currents move through their body. Participants may opt to have a third visit. At this visit, the breakfast will be high in protein....

Participants needed: 100
Trial details
Phase: Phase 2Age: 18-120Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Age >= 18 years [+35]

Consuming extreme macronutrient diet (e.g., very low-carbohydrate, high fat diet... [+23]

Status: Not yet recruiting

177Lu-DOTA-EB-TATE in Adult Patients With Metastatic, Radioactive Iodine Non-Responsive Oncocytic (Hurthle-Cell) Thyroid Cancer

Background: Oncocytic (Hurthle cell) thyroid cancer (HTC) is a rare disease with few treatment options. Researchers are developing a radioactive drug that targets a protein that appears in high numbers on HTC cancer cells. Objective: To test a radioactive drug (177LuDOTA-EB-TATE) in people with HTC. Eligibility: People aged 18 years and older with HTC. The HTC must have failed to respond to conventional radioactive treatment; it must also have spread to other parts of the body. Design: Participants will be screened. They will have a physical exam with blood tests. They will have imaging scans and a test of their heart function. 177LuDOTA-EB-TATE is infused into a vein. Participants will receive 4 infusions spaced 8 to 12 weeks apart. They will stay in the hospital for 4 to 10 days after each infusion. During and after each infusion, participants will remain in a lead-lined room until their radiation levels go down; this usually takes about 24 hours. Participants will have 4 to 6 follow-up visits in the weeks after each infusion. Procedures will vary at each visit, but may include more imaging scans; blood and urine tests; and tests of heart function. Participants will have 2 single-photon emission computerized tomography (SPECT) scans. SPECT scans show where the study drug is sticking to tumors or maybe other parts of their body. They will lie on a table while a machine rotates around them. Participants will fill in questionnaires about how their thyroid condition affects their life. Participants will have follow-ups visits for 5 years after their last study treatment.

Participants needed: 18
Trial details
Phase: Phase 1, Phase 2Age: 18-100Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Aged 18 years or older. [+3]

Pregnant or breastfeeding. [+33]

Status: Not yet recruiting

Assessing the Impact of Perceptions of Unpredictability on Objective Measures of Food Consumption and Metabolism

Background: Many people in the United States are overweight or obese. This natural history study will look into how life events during childhood can impact eating behaviors and weight gain as adults. Objective: To explore how childhood experiences affect adult eating behaviors. Eligibility: Healthy people aged 18 to 60 years. Design: Participants will have 3 clinic visits. They will be screened with blood tests. They will answer questions about their alcohol and tobacco use. At the next visit, participants will undergo these activities: Parts of their body (such as waist, neck, and thighs) will be measured with a tape. They will have an imaging scan to find out how much body fat they have. They will start wearing a device like a wristwatch that measures their physical activity. They will wear this device for up to 10 days. They will wear a device on their upper arm or belly that measures blood glucose (sugar) levels. Participants will wear this for 7-10 days. They will answer questions about their education, childhood, and routines. They will receive a kit to collect a stool sample at home. At the last visit, participants will have these tests: Participants will relax and breathe normally while wearing a clear, plastic canopy that fits over their entire head. Blood samples will be taken before and after participants drink a sugary drink. Participants will be offered a large selection of foods for lunch. They will eat as much as they want. Then they will answer questions about how they feel about food and themselves.

Participants needed: 110
Trial details
Age: 18-60Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Stated willingness to comply with all study procedures and availability for the... [+2]

Diabetes [+22]

Status: Not yet recruiting

Prevalence and Development of Liver Dysfunction in Hematopoietic Stem Cell Transplant

Background: Hematopoietic stem cell transplant (HSCT) is a common treatment for many cancers and other illnesses. But many people who have HSCT go on to develop liver dysfunction. Researchers want to know more about how and why this happens. In this natural history study, they will try to learn what factors lead to liver dysfunction; how underlying liver disease may affect the results of HSCT; and how HSCT may contribute to liver dysfunction. Objective: To understand the links between HSCT and liver dysfunction. Eligibility: Adults aged 18 years or older and children 3 to 17 years who are being evaluated for HSCT. Design: This study involves 11 visits in 4 years. Most visits will be in the first year. Before and after their HSCT, participants will undergo these tests: Physical exam, including blood tests and a test of heart function. Participants will provide stool samples. Liver biopsies. Samples of liver tissue will be removed. This may be done either by inserting a needle through the right side of the chest, or with a thin tube threaded to the liver from a vein in the neck. Adult participants will undergo this procedure 2 times: once before the HSCT and once about a year later. Imaging scans. Participants will lie on a bed that moves into either a cylinder or a donut-shaped machine. Ultrasound. Participants will lie still. A probe that uses sound waves will be slid over their skin to get pictures of the liver. Fibroscan exam. This is like an ultrasound that uses a special probe to measure the toughness of the liver. ...

Participants needed: 500
Trial details
Age: 3-90Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Male and female adults >=18 years of age and children 3-17 years of age [+1]

Pregnancy or lactation [+2]

Status: Not yet recruiting

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....

Participants needed: 60
Trial details
Phase: Phase 2Age: 18-65Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 9, 2026Locations: 1
Eligibility criteria

Adults 18 to 65 years of age [+1]

Hypersensitivity and associated allergic reactions to mirabegron or alpha-lipoic... [+27]

Status: Recruiting

Hepatic Lipid Metabolism-Alcohol Use Disorder

Patients with hepatic steatosis due to alcohol will be offered liver biopsies when they enter a detoxification program. The first biopsy will occur in the first week of admission and the second in the fourth week when the steatosis has resolved. The hepatic transcriptome will be compared,

Participants needed: 25
Trial details
Age: 18-100Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Any individual >=18 years of age who is enrolled in 14-AA-0181 and is seeking in... [+1]

Pregnancy [+11]

Status: Recruiting

Clinical and Molecular Characteristics of Primary Aldosteronism in Blacks

Background: The adrenal gland makes the hormone aldosterone. This helps regulate blood pressure. An adrenal gland tumor that makes too much aldosterone can cause high blood pressure and low potassium. The cause of these tumors is unknown, but sometimes they are inherited. Objective: To study the genes that may cause primary aldosteronism in Black individuals. Eligibility: People ages 18-70 who: Are Black, African American, or of Caribbean descent And have difficult to control blood pressure or primary aldosteronism Relatives of people with primary aldosteronism Design: Participants who are relatives of people with primary aldosteronism will have only 1 visit, with medical history and blood tests. Participants with primary aldosteronism or difficult to control blood pressure (suspected to possibly have primary aldosteronism) will be screened with a 1-2 hour visit. If they qualify, they will return for a hospital stay for 7-10 days. Tests may include: Medical history Physical exam Blood tests: Participants will have a small tube (IV catheter) inserted in a vein in the arm. They may drink a glucose-containing liquid or get a salt solution. If medically indicated, they may have invasive blood tests with a separate consent. Urine tests: Some require a high-salt diet for 3 days. Heart tests Scans: Participants lie in a machine that takes pictures of the body. A dye may be injected through a vein. Small hair sample taken from near the scalp. Kidney ultrasound Bone density scan: Participants lie on a table while a camera passes over the body. If the doctors feel it is medically necessary, they will offer participants treatment depending on their results. These treatments may cure the patient of their disease and may include: 1. Having one adrenal gland removed by the Endocrine surgeon under anesthesia. Patients will have follow-up visits 2-4 weeks after surgery. 2. Taking drugs to block the effects of aldosterone Participants may return about 1 year later to repeat testing....

Participants needed: 1,150
Trial details
Age: 7-70Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Age greater than or equal to 18y. [+5]

Individuals over the age of 70 years will be excluded because of the possibility... [+6]

Status: Recruiting

Clinical and Genetic Studies in Familial Non-medullary Thyroid Cancer

Background: \- Researchers are studying types of thyroid cancer that seem to cluster in families. Non-medullary thyroid cancer accounts for the vast majority of all types of thyroid cancer, but little is known about possible genes that may cause the cancer. More research is needed to develop the best ways to screen for familial non-medullary thyroid cancer (FNMTC) so that it can be diagnosed and treated at an early stage. Objectives: * To evaluate the natural history of FNMTC. * To determine the best screening strategy for FNMTC. * To identify genes that may indicate susceptibility to FNMTC. Eligibility: \- Individuals at least 7 years of age who have two first-degree relatives (e.g., parents, children, siblings) who have or have had non-medullary thyroid cancer or a documented diagnosis of non-medullary thyroid cancer and one living relative with documented non-medullary thyroid cancer. Design: * Participants will be evaluated by family history pedigree, physical examination, imaging (including possible neck ultrasound and radioactive iodine scans), and laboratory testing. * Participants who agree to have blood or other biological samples collected will be asked to enroll in an additional study to provide the appropriate samples and tissues. * After the initial study evaluation, participants who are not found to have a malignant thyroid tumor will be re-screened every year with non-invasive imaging studies. Participants who are found to have a malignant thyroid tumor will be informed of possible treatment options....

Participants needed: 500
Trial details
Age: 7-90Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Adults or minor (>= 7 years+), males and females. [+4]

Status: Recruiting

Natural History of Familial Carcinoid Tumor

This study will evaluate members in families with a history of small bowel carcinoid cancer to study the natural history of those family members that have the disease, determine ways to improve early detection by performing surveillance on those at risk but without disease and to identify the gene(s) that may cause the tumors. Familial carcinoid tumors usually originate in hormone-producing cells that line the small intestine or other cells of the digestive tract. The tumors are slow-growing and usually take many years before they cause symptoms. It is known that these tumors occur more often in some families and are then passed from one generation to the next by inherited genes. Members of families, including all siblings and offspring in which two or more immediate blood relatives have had small bowel carcinoid tumors are eligible for this study. In some cases unaffected spouses of family members diagnosed with carcinoid cancer are also requested to participate by donating a sample of blood only. Participants undergo a medical evaluation every 3 years during a 3- to 5-day hospital stay at the NIH Clinical Center. All participants have a personal and family medical history obtained and undergo a physical examination, blood and urine tests. People who already have a small bowel carcinoid tumor or are at risk of developing a carcinoid tumor have some or all of the following procedures to determine the presence of carcinoid tumor and its (omit next two words- location or) spread to other areas of the body: * Video Capsule Endoscopy: Visualization of the gastrointestinal tract by ingesting a disposable, "vitamin-pill sized" video capsule that has its own camera and light source. * CT of the chest abdomen and pelvis with oral and IV contrast : X-ray examination of the chest, abdominal and pelvis organs. * 18 FDOPA Positron emission tomography (PET) with CT for localization: Nuclear imaging scan to look at tumor activity. * MRI Liver with contrast - to determine if disease has spread to liver * Gallium 68 PET/CT-limited to individuals that have residual tumor. * Clinical and research blood work Should mid gut carcinoid tumors be found every participant will be assisted in determine what the best course of treatment will be for them. ...

Participants needed: 1,600
Trial details
Age: 18-100Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Male and female subjects >= 18 years of age [+10]

Members of families with multiple endocrine neoplasia (MEN) I, MEN II or other f... [+3]

Status: Recruiting

Urinary Vitamin C Loss in Diabetic Subjects

Several studies have reported that diabetic subjects have lower plasma vitamin C concentrations than non-diabetic subjects. Although urinary vitamin C loss in diabetic subjects was reported to be increased in two studies, these are difficult to interpret due to lack of controlled vitamin C intake, inadequate sampling, lack of control subjects, or methodology uncertainties in vitamin C assay and sample processing. Consequently, it is unclear whether diabetic subjects truly have both low plasma and high urine vitamin C concentrations. We propose that low plasma vitamin C concentrations in diabetic subjects are due in part to inappropriate renal loss of vitamin C in these subjects but not in healthy controls. We will study nondiabetic controls and cohorts with diabetes. Vitamin C concentrations in plasma, RBCs, and urine will be measured in outpatients. In those willing to be admitted to the Clinical Center, we will measure vitamin C pharmacokinetics to determine the relative bioavailability for vitamin C in individuals with and without abnormal urinary loss of vitamin C (or renal leak). Single nucleotide polymorphisms (SNPs) will be determined in genomic DNA responsible for the two proteins mediating sodium dependent vitamin C transport, SVCT1 and SVCT2. We will also explore mechanisms underlying abnormal urinary vitamin C loss.

Participants needed: 5,000
Trial details
Age: 18-65Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Aged 18-65 years. [+2]

Unable or unwilling to provide a signed and dated informed consent form [+5]

Status: Recruiting

Genetic Studies of Insulin and Diabetes

The study will allow researchers to obtain blood, plasma, DNA, and RNA for genetic studies of insulin. There will be a focus on the causes of insulin resistance and diabetes mellitus. Insulin is a hormone found in the body that controls the level of sugar in the blood. Insulin resistance refers to conditions like diabetes when insulin does not work properly. In this study researchers would like to compare patients with diabetes and other forms of insulin resistance to normal individuals. The study will investigate how insulin attaches to cells. Researchers will take 4 to 6 ounces (100-150 ml) of blood from adult patients and may request up to 12 ounces (one unit) of blood if necessary. Skin samples may be taken for a biopsy if further genetic testing is necessary. In addition some patients may be asked not to eat for up to 72 hours prior to testing.

Participants needed: 1,200
Trial details
Age: 6-120Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Patients with various syndromes of lipodystrophy [+28]

Patients with evidence for insulin resistance or a disorder associated with seve... [+13]

Status: Recruiting

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....

Participants needed: 2,000
Trial details
Age: 18-70Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

IINCLUSION AND

Status: Recruiting

Diagnosing and Treating Low Blood Sugar Levels

Hypoglycemia is the term used to refer to lower than normal levels of blood sugar. This study will continue to research the causes of hypoglycemia. Patients involved in the study will be admitted to the Clinical Center of the National Institutes of Health and undergo tests for evaluating blood sugar. Patients will be required to refrain from eating for a set period of time and will undergo blood tests for insulin levels and several other specific diagnostic tests related to insulin secretion. The patients will be under supervision and will be provided with appropriate medical and surgical attention as needed....

Participants needed: 1,500
Trial details
Age: 18-120Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Male, females ages >= 18. [+1]

Patients with significant cardiac disease will be excluded. [+2]

Status: Recruiting

Studies on Tumors of the Thyroid

Participants in this study will be patients diagnosed with or suspected to have a thyroid nodule or thyroid cancer. The main purpose of this study is to further understand the methods for the diagnosis and treatment of thyroid nodules and thyroid cancer. Many of the test performed are in the context of standard medical care that is offered to all patients with thyroid nodules or thyroid cancer. Other tests are performed for research purposes. In addition, blood and tissue samples will be taken for research and genetic studies.

Participants needed: 2,500
Trial details
Age: 6-98Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 8, 2026Locations: 1
Eligibility criteria

Male or female, adults or children >= 6 months+. [+2]

Status: Recruiting

New Heart Imaging Techniques to Evaluate Possible Heart Disease

Background: \- Imaging tests, such as magnetic resonance imaging (MRI), can provide information about heart and blood vessels. The tests let doctors can see the amount of blood vessel narrowing and vessel wall thickness. This information may help diagnose and treat heart disease and other conditions that lead to heart attacks. Better MRI methods are needed to improve heart disease diagnosis, especially by avoiding the use of radiation. Researchers are testing new techniques to improve the quality of heart MRI, compared with more complex studies like catheterization or angiography. Objectives: \- To compare heart MRI techniques with other tests used to diagnose heart disease. Eligibility: \- People at least 18 years of age who either have or may have heart disease, or are healthy volunteers. Design: * Participants will be screened with a physical exam, medical history, and blood tests. * They will have an angiography to study the inside of blood vessels. This test is an x-ray study of the blood vessels. It will be done either separately or as part of a set of tests to diagnose possible heart disease. * Participants will have at least one and up to five MRI scans. The scans will involve different methods of studying the heart and blood vessels. Participants may also have a computed tomography scan to confirm the findings of an MRI scan. * No treatment will be provided as part of this protocol.

Participants needed: 4,000
Trial details
Age: 18-100Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 7, 2026Locations: 1
Eligibility criteria

Subjects with or without history of cardiovascular diseases and with various deg... [+4]

Implanted cardiac pacemaker or defibrillator [+39]

Status: Recruiting

Diet Order Effects of Low Fat vs. Low Carb Diets on Body Fat Change

Background: In a previous study, participants were lived at the NIH and randomly received either a low-fat or a low-carbohydrate diet for 2 weeks and then switched to the other diet for 2 more weeks. Participants who received the low-carbohydrate diet first lost more body fat at the end of the study than those who received the low-fat diet first. Researchers want to see if they can repeat that result in a longer weight loss study when participants live at home. Objective: To test the effects of diet order in people receiving either a low-fat or low-carbohydrate diet first for 4 weeks and then immediately switched to the other diet for another 4 weeks. Eligibility: Adults aged 19 to 50 years with a body mass index of 25 or more. Design: Participants will complete the study at their homes, but there will be 3 required visits to the NIH. Participants will drink a special type of water 2 weeks before the baseline NIH visit and collect urine samples at home to measure how many calories they burn. Before the diets begin, participants will visit the NIH for baseline testing when they will have a metabolism test while relaxing in a bed with a plastic hood over their head to collect the air they breathe out. They will have scans to measure their bone density and how much muscle and body fat they have. They will give stool, blood, and urine samples. Participants will be asked to eat a specific diet for 4 weeks followed by a different diet for 4 weeks. All meals will be delivered to the participants' homes. They will eat only the foods delivered. Participants will weigh themselves daily. They will wear a monitor to track their physical activity and a sensor to measure their glucose levels. They will prick their finger each morning to test a drop of blood for ketones. Participants will meet virtually as a group with the study team weekly. Participants will have two more NIH visits towards the end of each diet period....

Participants needed: 42
Trial details
Age: 18-50Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 6, 2026Locations: 1
Eligibility criteria

Stated willingness to comply with all study procedures and availability for the... [+4]

Subjects with cardiac pacemakers or other implants that may be affected by or af... [+16]

Status: Recruiting

A Natural History Study of Metabolic Sizing in Health and Disease

Background: Scientists have long used simple measures (such as height and weight) to estimate how much a person s body uses food (calories) as energy, as commonly called the metabolic rate. But metabolism varies among people with similar body sizes. Scientists now believe the old formulas for estimating metabolic rates may not work well for all people. Researchers want to find more accurate ways to measure a person s metabolism. Objective: This natural history study will examine the relationships between metabolism, body composition, and body surface area in a wide range of people. Eligibility: Healthy children and adults aged 2 years or older. Also, people aged 2 years or older with conditions that may alter metabolism. These may include diabetes, obesity, renal disease, or cancer. Design: Participants will spend 2 days and 1 night in the hospital. They will provide a medical history and answer questions about their activity levels, the foods they eat, and their lifestyle. They will also eat a special diet. Participants will undergo many tests: They will lie in a bed with a clear hood covering their head for 30 to 45 minutes to measure the gases in their breath. They will lie on a padded table for about 15 minutes while their body is scanned. They will stand on a platform while a 3D scanner measures their body. They will have a test to measure how fast an electric signal moves through their body. They will grip an instrument to measure the strength of their hands. They will drink salty water and provide blood and urine samples. Participants may be invited to return for these 2-day visits up to 8 times per year. Return visits must be at least 2 weeks apart.

Participants needed: 2,000
Trial details
Age: 2-99Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 6, 2026Locations: 1
Eligibility criteria

Male or female, aged >=2 years [+3]

Participants over 200 kg due to the weight limit of the equipment. [+6]

Status: Recruiting

The Role of 68-Gallium-DOTATATE-PET/CT in the Imaging of Metastatic Thyroid Cancer

Background: About 5% to 10% of differentiated thyroid cancers become resistant to standard treatment with radioactive iodine. In these cases, treatment options are limited and generally not effective. Researchers want to see if they can better detect thyroid tumors by using a compound called 68Gallium-DOTATATE. This compound may bind to a tumor and make it visible during a positron emission tomography/computed tomography (PET/CT) scan. This information might help guide future research and treatment. Objective: To identify the people with thyroid cancer whose tumors have a high uptake of 68Gallium-DOTATATE as analyzed by imaging with PET/CT. Eligibility: People ages 18 years and older with thyroid cancer that has spread outside of the thyroid. Design: Participants will have a medical exam. They will give blood and urine samples. Some samples will be used for research. Participants will have imaging scans that follow standard of care. These scans may include: CT scan of the neck, chest, abdomen, and pelvis Bone scan Magnetic resonance imaging of the brain, spine, or liver 18-FDG-PET/CT as needed Participants will have a PET/CT scan. They will get an intravenous (IV) line. They will get an IV injection of 68Gallium-DOTATATE. It contains radioactive tracers. The PET/CT scanner is shaped like a large donut. It contains crystals. The crystals pick up small radiation signals that are given off by the tracers. The CT part of the scan uses low-dose x-rays. The pictures made by the scanner show where the tracers are in the body. The session will last 90 minutes. Participation will last for about 3 months.

Participants needed: 54
Trial details
Phase: Phase 2Age: 18-98Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 5, 2026Locations: 1
Eligibility criteria

Male or female, aged >18 years. [+6]

Status: Recruiting

Natural History of Thyroid Function Disorders

Participants in this study will be patients diagnosed with or suspected to have a thyroid function disorder. These conditions may include: hypothyroidism, hyperthyroidism, thyroid hormone resistance, Graves' Dermopathy, and thyroid-stimulating hormone (TSH) secreting pituitary adenomas. The main purpose of this study is to further understand the natural history, clinical presentation, and genetics of thyroid function disorders. Many of the tests performed are in the context of standard medical care that is offered to all patients with thyroid function disorders. In addition, blood and tissue samples may be taken for research and genetic studies.

Participants needed: 2,500
Trial details
Age: 6-98Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 5, 2026Locations: 1
Eligibility criteria

Participants with known or suspected thyroid abnormalities (e.g. hypothyroidism,... [+4]

Stated willingness to comply with all study procedures and availability for the... [+14]

Status: Recruiting

Study of Endocrine-Related Conditions and Physiology

Background: Endocrine disorders involve changes to glands that produce hormones. Hormones are released by these glands into the blood so they can direct the function of other tissues in the body. Researchers want to study people who may have endocrine disorders. They want to learn more about the conditions that affect endocrine glands. Objective: To study adults with a variety of endocrine disorders for research and physician education. Eligibility: Adults ages 18 and older who have an endocrine or metabolic-related disorder Healthy volunteers 18 and older Design: Participants will be screened with a review of their medical records. Participants will have a physical exam and medical history. The length of the study and the schedule will vary by participant. Tests may include: Blood and urine tests Stool and saliva samples Imaging studies: Participants will lie on a table while a machine takes pictures of the body. They may be injected with a substance to make their organs more visible in the pictures. Tests of endocrine tissue function Consultation with other specialists Sleep study Medical photographs Participants may be treated for their endocrine disorder. This could include: Surgery. If tissue is removed during surgery, it may be studied. Radiation Medicine Participants may have genetic testing. This will be done with a small amount of blood, cells from a cheek swab, or saliva. Sponsoring Institution: National Institute of Digestive, Diabetes and Kidney Disease

Participants needed: 1,000
Trial details
Age: 18-90Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 2, 2026Locations: 1
Eligibility criteria

Adult men and women age 18 years or older. [+2]

Unstable participants and participants with severe organ failure, or those with... [+2]

Status: Recruiting

Natural History of Noncirrhotic Portal Hypertension

Background: \- Noncirrhotic Portal Hypertension (NCPH) is caused by liver diseases that increase pressure in the blood vessels of the liver. It seems to start slowly and not have many warning signs. Many people may not even know that they have a liver disease. There are no specific treatments for NCPH. Objectives: \- To learn more about how NCPH develops over time. Eligibility: \- People age 12 and older who have NCPH or are at risk for getting it. In the past year, they cannot have had other types of liver disease that typically result in cirrhosis, liver cancer, or active substance abuse. Design: * Participants will have 2 screening visits. * Visit 1: to see if they have or may develop NCPH. * Medical history * Physical exam * Urine and stool studies * Abdominal ultrasound * Fibroscan. Sound waves measure liver stiffness. \<TAB\>- Visit 2: * Blood tests * Abdominal MRI * Echocardiogram * Questionnaire * Liver blood vessel pressure (hepatic venous portal gradient (HVPG)) measurement. This is done with a small tube inserted in a neck vein. * They may have a liver biopsy. * All participants will visit the clinic every 6 months for a history, physical exam, and blood tests. They will also repeat some of the screening tests yearly. * Participants with NCPH will also have: * Upper endoscopy test. A tube inserted in the mouth goes through the esophagus and stomach. * At least every 2 years: Esophagogastroduodenoscopy. * At least every 4 years: testing including HVPG measurements and liver biopsy. * Participants without NCPH will also have: * Liver biopsy and HVPG measurements to see if they have NCPH. * Every 2 years: abdominal MRI and stool studies. * The study will last indefinitely.

Participants needed: 400
Trial details
Age: 12-100Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 2, 2026Locations: 1
Eligibility criteria

Male or female, aged >= 18 years of age, and minors 12-17 years of age. [+2]

Pregnancy. [+12]

Status: Recruiting

Prospective Evaluation of 68Ga-DOTATATE PET/CT, Octreotide and F-DOPA PET Imaging in Ectopic Cushing Syndrome

Between 10% and 15% of patients with endogenous hypercortisolism (Cushing syndrome) have ectopic (non-pituitary) production of adrenocorticotropin hormone (ACTH) that causes cortisol excess. In approximately 50% of these patients, the tumoral source of ACTH cannot be found initially despite very detailed and extensive imaging, including studies such as computed tomography, magnetic resonance imaging, and octreotide scan (Octreoscan) using the standard dose of indium- 111 pentetreotide (\[111In-DTPA-D-Phe\]-pentetreotide). The sensitivity and specificity of structurally based imaging studies depends on anatomic alterations and the size of the tumor. In contrast, positron emission tomography (PET) and somatostatin ligand imaging detect pathologic tissue based on physiologic and biochemical processes within the abnormal tissue. This protocol tests the ability of \[18F\]-L-3,4-dihydroxyphenylalanine (18F-DOPA) PET, and the somatostatin imaging analogue, 68Ga-DOTATATE-PET, to localize the source of ectopic ACTH production.

Participants needed: 80
Trial details
Phase: Phase 2Age: 18-80Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Oct 2, 2026Locations: 1
Eligibility criteria

18 - 90 years of age [+4]

Pregnancy or lactation; the radiation associated with PET and CT scans may be ha... [+6]