Prevalence and Cardiovascular Effects of Growth Hormone Deficiency in Abdominal Obesity
Condition: Obesity; Growth Hormone
MeSH terms: Obesity; Obesity, Abdominal
Study type: Observational

Summary: 
      Obesity is one of the leading causes of cardiovascular-related diseases, including diabetes
      and heart disease. Obesity, and more specifically abdominal obesity, may cause decreased
      growth hormone (GH) levels. It is believed that GH deficiency may contribute to increased
      cardiovascular risk by affecting insulin resistance, inflammatory markers, and blood
      cholesterol levels. This study will determine the occurrence of GH deficiency in abdominal
      obesity and whether GH deficiency is associated with increased cardiovascular risk beyond
      traditional risk factors.
    

Detailed description: 
      Obesity is associated with significant morbidity and mortality and is a primary public health
      concern. Both the incidence and prevalence of obesity have increased over the last several
      decades, with obesity now affecting an estimated 31% of the American population. Recent data
      suggest that people with abdominal obesity commonly exhibit low levels of GH, which affects
      the body's growth rate and the way the body uses food for energy. Low GH levels and excess
      abdominal fat have been linked to improper functioning of the cardiovascular system and,
      therefore, may increase one's risk of cardiovascular disease. This study will determine the
      prevalence of GH deficiency in abdominal obesity and whether GH deficiency is associated with
      increased cardiovascular risk beyond traditional risk factors.

      Participation in this observational study will last between 2 and 4 weeks. The study will
      consist of two outpatient visits, held at either the Massachusetts General Hospital or
      Massachusetts Institute of Technology. Visit 1 will last 4 hours and will include a physical
      exam, medical history, blood draw, urine sampling, indirect calorimetry test, and growth
      hormone releasing hormone (GHRH)+Arginine stimulation test. Eligible participants will return
      within the next 3 weeks for Visit 2, which will last 5 hours. Before the second visit,
      participants will be asked to record their food intake for 4 days on a food record. During
      the visit, participants will have a repeat physical exam, urine sampling, and blood draw.
      Participants will also undergo an oral glucose tolerance test, whole body DEXA scan,
      abdominal computed tomography (CT) scan, and a carotid ultrasound. Participation in the study
      will end after Visit 2.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        The study population will include participants from the community at large who are able to
        come to either the Massachusetts General Hospital (MGH) Weight Center or Massachusetts
        Institute of Technology for study visits.
      
Biospecimen description: 
      Samples will include serum, plasma, whole blood, and white blood cells
    
Keywords: Growth Hormone Deficiency; Cardiovascular Disease; Intra-abdominal Fat; Insulin Resistance