GUARDIAN: IRAS (IRAS Classic)

The Insulin Resistance Atherosclerosis Study (IRAS) was an epidemiologic cohort study designed to examine the relationship between insulin resistance and carotid atherosclerosis across a range of glucose tolerance. Individuals of self-reported Mexican-American ethnicity were recruited in San Antonio, TX and San Luis Valley, CO. Recruitment was balanced across age and glucose tolerance status. GUARDIAN includes 173 individuals from the IRAS. Insulin sensitivity was obtained by FSIGT.]]>
Between October 1992 and April 1994, IRAS recruited 1,625 participants from four clinical centers located in San Antonio, TX, San Luis Valley, CO, Oakland, CA and Los Angeles, CA. The goal of sampling strategies in IRAS was to obtain representation of participants over the spectrum of glucose metabolism ranging from normal to diabetic. Baseline Inclusion Criteria: Men and women Age 40-69 years Hispanic, non-Hispanic Whites and non-Hispanic Blacks. Baseline Exclusion Criteria: Current insulin treatment or any insulin treatment within the past five years Decompensated heart failure (recent worsening with weight gain, increasing edema, increasing dyspnea or orthopnea, rales) Decompensated emphysema or chronic lung disease Unstable angina Cancer, other than skin cancer, for which the person is currently being treated Seizure disorder or epilepsy Kidney dialysis, transplant, or renal failure A serious illness within the last month (e.g., heart attack, stroke, or major surgery) Treatment with oral, i.m., or i.v. cortisone, prednisone or other steroids Pregnancy Breast cancer treated with surgery or radiation Severe limitation of caloric intake ( < 800 calories) Obvious mental disability as noted in the screening interview. A subset of IRAS Study participants were included in the genotyping study: Hispanics only; without diabetes; with insulin sensitivity obtained by frequently sampled intravenous glucose tolerance test; and providing consent for genetic studies.]]>
IRAS was established in 1992 by the National Heart, Lung and Blood Institute (NHLBI). The IRAS cohort of 1625 participants was initially recruited in 1992-1994 from four clinical centers located in San Antonio, TX, San Luis Valley, CO, Oakland, CA and Los Angeles, CA. A follow-up study was conducted in 1998-1999. The current (genotyped) data set includes 173 Hispanic IRAS participants from San Antonio and San Luis Valley. A family study was conducted following the completion of IRAS, which was named the IRAS Family Study. It included probands from IRAS with large families. Consequently, the original IRAS Study is sometimes referred to as IRAS Classic.]]>