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Diabetes and Cardiovascular Risk In Mexico City (San Antonio Heart Study)

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ClinicalTrials.gov Identifier: NCT00005146
Recruitment Status : Completed
First Posted : May 26, 2000
Last Update Posted : March 8, 2016
Sponsor:
Collaborator:
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
The University of Texas Health Science Center at San Antonio

Tracking Information
First Submitted Date May 25, 2000
First Posted Date May 26, 2000
Last Update Posted Date March 8, 2016
Study Start Date May 1979
Primary Completion Date Not Provided
Current Primary Outcome Measures Not Provided
Original Primary Outcome Measures Not Provided
Change History
Current Secondary Outcome Measures Not Provided
Original Secondary Outcome Measures Not Provided
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title Diabetes and Cardiovascular Risk In Mexico City (San Antonio Heart Study)
Official Title Diabetes and Cardiovascular Risk In Mexico City (San Antonio Heart Study)
Brief Summary To determine factors beyond obesity which contribute to diabetes and cardiovascular risk in Mexicans and Mexican Americans. To test the hypothesis that at any given level of adiposity Mexican Americans will be more insulin resistant than Anglos and that the insulin resistance in Mexican Americans is proportional to the degree of Native American ancestry.
Detailed Description

BACKGROUND:

The present study was preceded by the earlier San Antonio Heart Study 1 supported under this grant. The San Antonio Heart Study 1 was a population-based survey of diabetes and cardiovascular risk factors in Mexican American and non-Hispanic whites conducted from 1979 to 1982. Participants included all men and non-pregnant women ages 24 to 64, who resided in households randomly sampled from three socio-culturally distinct neighborhoods of San Antonio. The low-income barrio residents were almost exclusively traditional Mexican-Americans. The middle-income neighborhood was ethnically balanced with equal numbers of Mexican Americans and Anglos whereas the upper income suburb was approximately 90 percent Anglo. Risk factors measured included obesity, glucose intolerance, hypertriglyceridemia, low levels of high density lipoprotein cholesterol, and blood pressure. The total number of people who were examined medically was 2,386, divided as follows: 1,288 Mexican Americans; 929 Anglos; and 169 other Hispanics such as Cubans. The San Antonio Heart Study was designed to test the hypothesis that as Mexican Americans became progressively more affluent and acculturated to 'mainstream' United States culture, they would gradually lose their diabetic pattern of cardiovascular risk factors of obesity, diabetes, and hypertriglyceridemia.

DESIGN NARRATIVE:

Beginning in 1979, a random sample was conducted to select participants. Sampling was performed to match the two groups on obesity, thereby enabling an analysis of the ethnic differences in diabetes and cardiovascular risk factors independent of the confounding effects of obesity. For those selected, an interview and medical examination were conducted in a mobile clinic. The interview consisted of a personal and family history of diabetes and cardiovascular risk, knowledge of and attitudes towards cardiovascular risk factors, dietary questionnaire, Rose Angina questionnaire, intermittent claudication questionnaire, and medication history. The medical examination consisted of anthropometric measurements, plasma glucose, plasma insulin, hemoglobin, serum cholesterol, triglyceride, HDL, LDL, and VLDL, genetic markers, blood pressure, skin color and electrocardiogram. It was estimated that 400 diabetics would be available over the four years of the study to permit a Diabetic Recall Examination. The purpose of the Diabetic Recall Examination was to assess possible end-organ complications of diabetes involving the eye, kidney, peripheral and autonomic nervous systems, and the peripheral vascular system. The assessment provided baseline data on diabetics which was used for a prospective incidence study. Beginning in 1989, a prevalence survey of type II diabetes mellitus and cardiovascular risk factors was conducted in a low-income barrio in Mexico City. Information collected on this population included demographic data, socioeconomic status, level of acculturation, medical history, diet, exercise, and smoking. The physical examination included measurements of blood pressure, obesity, body fat distribution, and skin color. The laboratory examination included measurements of lipids and lipoproteins, oral glucose tolerance tests, fasting and post-glucose load insulin concentrations and genetic markers.

Beginning in FY 1989, Michael Stern and associates carried out an epidemiologic study of type II diabetes mellitus and cardiovascular risk factors in a low-income barrio of Mexico City and compared results to those obtained in San Antonio. They recruited and interviewed subjects for data on demographics, socioeconomic status, level of acculturation, medical history, health habits including diet, physical exercise, and smoking. The physical examination included blood pressure, obesity, body fat distribution, skin color, the latter to estimate percent Native American genetic admixture. The laboratory examination included measurements of lipids and lipoproteins, an oral glucose tolerance test to determine the prevalence of diabetes according to the National Diabetes Data Group criteria, fasting and post-glucose load insulin concentrations, and genetic markers.

The study was renewed in 1996 through August, 2001. A 3.25 year followup examination (FU1) of a cohort of 2,296 Mexican men and women, ages 35-64 years at baseline, was completed. The cohort was re-examined at 3.25-year intervals (6.5 years (FU2) and 9.75 years (FU3) after baseline). The investigators tested the hypothesis that different risk factors would prevail in the early (more than 3.25 years prior to conversion to diabetes) than in the late (3.25 years or less prior to conversion) prediabetic period. They hypothesized that in the early prediabetic period risk factors associated with the Insulin Resistance Syndrome would predominate, i.e., high "specific" insulin concentration (measured by a specific immunoassay), hypertriglyceridemia, low HDL-cholesterol, and hypertension, whereas in the late prediabetic period factors associated with insulin secretory failure, i.e., increased proinsulin and low "specific" insulin, would predominate.

Michael Stern and associates assessed carotid wall thickness by ultrasonography on all subjects at FU1 and planned to repeat this at FU2. They measured advanced glycation endproduct (AGE)-modified apolipoprotein B and a panel of inflammatory risk factors (serum albumin, serum amyloid A, alpha1-acid glycoprotein, and C-reactive protein) on stored contingency specimens from baseline and FU1 in order to determine if these factors predicted accelerated thickening of carotid walls and/or the development of type II diabetes. They also quantified the extent to which carotid wall thickness and ECG documented myocardial infarction preceded clinical diabetes as predicted by the "common soil" hypothesis, i.e., the hypothesis that both type II diabetes and atherosclerosis have common genetic and environmental antecedents.

Study Type Observational
Study Design Not Provided
Target Follow-Up Duration Not Provided
Biospecimen Not Provided
Sampling Method Not Provided
Study Population Not Provided
Condition
  • Cardiovascular Diseases
  • Heart Diseases
  • Diabetes Mellitus, Non-insulin Dependent
  • Diabetes Mellitus
Intervention Not Provided
Study Groups/Cohorts Not Provided
Publications *

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status Completed
Enrollment Not Provided
Original Enrollment Not Provided
Actual Study Completion Date August 2002
Primary Completion Date Not Provided
Eligibility Criteria No eligibility criteria
Sex/Gender
Sexes Eligible for Study: Male
Ages up to 100 Years   (Child, Adult, Older Adult)
Accepts Healthy Volunteers No
Contacts Contact information is only displayed when the study is recruiting subjects
Listed Location Countries Not Provided
Removed Location Countries  
 
Administrative Information
NCT Number NCT00005146
Other Study ID Numbers 1017
R01HL024799 ( U.S. NIH Grant/Contract )
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement
Plan to Share IPD: No
Responsible Party The University of Texas Health Science Center at San Antonio
Study Sponsor The University of Texas Health Science Center at San Antonio
Collaborators National Heart, Lung, and Blood Institute (NHLBI)
Investigators
Investigator: Michael Stern University of Texas
PRS Account The University of Texas Health Science Center at San Antonio
Verification Date March 2016