What this Trial Is About

Background: Platelets are a type of blood cell that play a critical role in bleeding, forming blood clots, and healing. Researchers want to know more about platelets work in healthy people. They want to look at how platelets clump together, how blood clots, and how genes and proteins work. They also want to study how these processes change over time and how they are affected by factors such diet, exercise, weight, and new health problems. Objective: To study how platelets function in healthy people. Eligibility: Healthy people aged 18 years and older. Design: Researchers will review participants medical history. They will ask about the participant s family history and any drugs they take. Participants will have a clinic visit once every 6 or 7 months for 10 years. Each visit will be 2 to 3 hours. At each visit, participants will have several tests and procedures: A physical exam, including vital signs. Hip and ankle circumference will be measured. Urine collection. Blood tests. About 10 tablespoons of blood will be drawn. Participants will be asked to fast for 10 hours and avoid drugs like aspirin or Advil for 7 days before each draw. Some of the blood may be used for gene studies. Some may be used to create stem cells for research. Stem cells are cells that can be used to make other types of cells. Surveys and questionnaires. Participants will answer questions about habitual activity, diet, smoking, drugs and alcohol, sleep, illness, and other health issues. These surveys may be done online, via email, or by phone.

Platelet Volunteers, Longitudinal and Multi-omic Study