A Suspected Association Between Sarcoidosis and Development of Diabetes Mellitus

The purpose of the study is to determine the characteristics of patients with diabetes and sarcoidosis and to compare them with those of patients with diabetes and no sarcoidosis. The investigators will approach these aims by measuring hemoglobin A1c, C peptide, insulin levels, and 2-hour glucose tolerance test results on the study population as well as collecting clinical data from records. Three groups of patients will be identified from pulmonary and endocrinology clinics at the University of Alabama at Birmingham. The first group will have a diagnosis of sarcoidosis without diabetes, the second group will have a diagnosis of both sarcoidosis and diabetes, and the third group will have a diagnosis of diabetes without sarcoidosis. Sample size is not pre-determined, but investigators anticipate this number to be less than 100. These patients will be asked in person during an office visit to join the study. For each patient who agrees to join, at a clinic visit, investigators will review and sign consent. Following the visit or at a time convenient for each patient, study subjects will undergo a fasting plasma venous sample collection for a hemoglobin A1c, C peptide, insulin level and perform a 2-hour oral glucose tolerance test. The degree of glucose intolerance and prevalence of diabetes will be analyzed and compared between the groups and to historical published control data via T test comparisons. At a later separate visit, patients recruited will undergo ultrasound of the pancreas to assess pancreatic size and morphology.