Effect of Diet on Vascular Disease in Pre-Menopausal Women
Condition: Cardiovascular Diseases; Vascular Disease; Inflammation; Insulin; Triglycerides
MeSH terms: Cardiovascular Diseases; Vascular Diseases; Inflammation
Study type: Observational

Summary: 
      African Americans have a higher prevalence of vascular disease than Caucasians. Vascular
      disease can lead to heart attacks, strokes and even amputations. Insulin, a hormone which is
      secreted by the pancreas, affects not only glucose and fat metabolism but also vascular
      disease. Impairment of insulin s ability to remove glucose from the circulation is known as
      insulin resistance. To overcome insulin resistance the pancreas secretes extra insulin. These
      high levels of insulin affect circulating triglyceride levels by both promoting production of
      triglyceride by the liver and interfering with clearance of triglyceride from the
      circulation. Triglyceride in turn contributes to the development of vascular disease by
      causing both inflammation and hypercoagulability.

      Surprisingly African Americans are more insulin resistant and have a higher rate of vascular
      disease than Caucasians but have lower triglyceride levels. Because of the high rate of
      vascular diseases in African Americans, our aim is to determine if the adverse effects of
      triglyceride occur at a lower level in African Americans than Caucasians. To achieve this
      goal we will determine if there are differences in the effect of a meal on triglyceride
      levels and vascular function in a representative cohort of African American and Caucasian
      women.

      For this study we will enroll 96 women (48 African American and 48 Caucasian women). We are
      recruiting women because ethnic differences in triglyceride are even greater in women than
      men. We are enrolling women between the ages of 18 and 65 years. The study will involve
      several outpatient visits to the NIH Clinical Center. The first visit will be a screening to
      determine eligibility. At the second visit a test to measure insulin resistance will be
      performed. This test is called a frequently sampled intravenous glucose tolerance test. The
      third visit will be for the test meal. Before and at 2, 4 and 6 hours after the meal, blood
      will be drawn and vascular function measured. Vascular function is determined by taking blood
      pressure and then measuring blood flow in the arm with ultrasound. It is possible that
      individual differences in diet could affect the results of the vascular study on the day of
      the test meal. Therefore for 7 days prior to the test meal, the NIH Clinical Center will
      provide to each participant all their meals in the form of either trays or meals in a box.
      These meals will be consistent with the typical American diet and be 33% fat, 15% protein and
      52% carbohydrate. In designing these meals, the dietician will take into account individual
      food preferences.

      This study is being performed in collaboration with the Harvard School of Public Health, the
      University of Texas Southwestern Medical Center and Indiana University. Therefore some blood
      drawn during Visits 2 and 3 will be sent coded, without personal identifiers, to each
      institution for analyses.

      ...
    

Detailed description: 
      African Americans have a higher prevalence of vascular disease than Caucasians. Vascular
      disease can lead to heart attacks, strokes and even amputations. Insulin, a hormone which is
      secreted by the pancreas, affects not only glucose and fat metabolism but also vascular
      disease. Impairment of insulin s ability to remove glucose from the circulation is known as
      insulin resistance. To overcome insulin resistance the pancreas secretes extra insulin. These
      high levels of insulin affect circulating triglyceride levels by both promoting production of
      triglyceride by the liver and interfering with clearance of triglyceride from the
      circulation. Triglyceride in turn contributes to the development of vascular disease by
      causing both inflammation and hypercoagulability.

      Surprisingly African Americans are more insulin resistant and have a higher rate of vascular
      disease than Caucasians but have lower triglyceride levels. Because of the high rate of
      vascular diseases in African Americans, our aim is to determine if the adverse effects of
      triglyceride occur at a lower level in African Americans than Caucasians. To achieve this
      goal we will determine if there are differences in the effect of a meal on triglyceride
      levels and vascular function in a representative cohort of African American and Caucasian
      women.

      For this study we will enroll 96 women (48 African American and 48 Caucasian women). We are
      recruiting women because ethnic differences in triglyceride are even greater in women than
      men. We are enrolling women between the ages of 18 and 65 years. The study will involve
      several outpatient visits to the NIH Clinical Center. The first visit will be a screening to
      determine eligibility. At the second visit a test to measure insulin resistance will be
      performed. This test is called a frequently sampled intravenous glucose tolerance test. The
      third visit will be for the test meal. Before and at 2, 4 and 6 hours after the meal, blood
      will be drawn and vascular function measured. Vascular function is determined by taking blood
      pressure and then measuring blood flow in the arm with ultrasound. It is possible that
      individual differences in diet could affect the results of the vascular study on the day of
      the test meal. Therefore for 7 days prior to the test meal, the NIH Clinical Center will
      provide to each participant all their meals in the form of either trays or meals in a box.
      These meals will be consistent with the typical American diet and be 33% fat, 15% protein and
      52% carbohydrate. In designing these meals, the dietician will take into account individual
      food preferences.

      This study is being performed in collaboration with the Harvard School of Public Health, the
      University of Texas Southwestern Medical Center and Indiana University. Therefore some blood
      drawn during Visits 2 and 3 will be sent coded, without personal identifiers, to each
      institution for analyses.
    

Time perspective: Prospective
Keywords: Women; Healthy Volunteers; Triglyceride; Healthy Volunteer; HV