The project objective is to validate a new indirect estimate of insulin status in both
pregnant African-American women and Caucasian women in southern Louisiana who are at risk
for gestational diabetes mellitus. There are racial differences in carbohydrate metabolism
that are potentially linked to complications during pregnancy and to increased risks of
obesity and diabetes in later life. The investigators will explore the use of indexes of
insulin status to identify the metabolic risk profile of pregnant women which may vary by
race. Understanding whether there are differences which vary by race may influence clinical
screening and treatment of pregnant women.
The major goal of our proposed study is to validate a new approach to estimating insulin
sensitivity and ß-cell function in African-American women compared to non-Hispanic white
women in southern Louisiana who are at a high risk for gestational diabetes mellitus (GDM).
We will determine whether the whole body insulin sensitivity index (WBISI) and insulinogenic
index (IGI) [derived from an oral glucose tolerance test (OGTT)] can be used during 24-28
weeks of pregnancy to accurately estimate the degree of insulin resistance relative to
ß-cell function in women with GDM in those with impaired glucose tolerance (IGT) as well as
those who are glucose tolerant. Fasting values will also be assessed using the homeostasis
model assessment (HOMA-IR and HOMA-%B) to evaluate insulin resistance and ß-cell function.
We will explore the potential use of these measures to define the metabolic risk profile of
these pregnant women and compare them with obstetric outcomes. We will determine if there
are differences in risk that vary by race. Second, given the high likelihood that women who
manifest GDM will develop type 2 diabetes mellitus (DM), identification of these patients by
ethnic group or other independent determinants will permit intervention after delivery that
might delay or prevent the onset of type 2 DM.
- 18-42 years of age
- at 20-30 weeks of gestation
- Caucasian or African-American and non-users of medications known to influence
- <18 years or >42 years of age
- non-Caucasian or non-African-American ethnicity
- use of drugs that could interfere with glucose or insulin metabolism; or health
problems such as diabetes mellitus or liver, heart, lung and kidney diseases