Study Abstract

Background The fetal origins of chronic disease states that the development of disorders such as type 2 diabetes, hypertension, and heart disease, are related to being born small with subsequent obesity. Several studies have demonstrated the validity of this hypothesis. However, a review of the literature did not reveal any studies that examined this relationship in African American women, a population that is at high risk for developing type 2 diabetes.

Purpose of Study: This study tests the validity of the fetal origins hypothesis in African American women 38-57 years of age. In addition, it examines the relationship of type 2 diabetes, abdominal obesity, and a wide spectrum of birthweights in this population, including those who were born heavy; that is >4,000 grams (~9 pounds).

Outcome Measure: A physician diagnosis of type 2 diabetes, as reported by study participants.

Exposure Measures and Other Factors: Birthweight, gestational age, current waist circumference, and waist-to-hip ratio are the exposure measures. Other factors include body mass index (BMI), physical activity, family history of diabetes, personal history of gestational diabetes, blood pressure, smoking, and.

Research Design and Methods: This is a case-control observational study. The sample includes 377 women. Cases are 121 African American women 38-57 years of age who reported a physician diagnosis of type 2 diabetes. Controls are 243 women. To verify control status, women were screened for elevated fasting plasma glucose (FPG) using capillary blood from a finger prick, with a cut-point of FPG less than 126 milligrams per deciliter (mg/dL), as defined by the American Diabetes Association. During control status verification, if a potential control's FPG was equal to or greater than 126 milligram, she was defined as having "undiagnosed diabetes" and will be excluded from the study. There are 13 women who could not be classified as cases or controls. All study participants were given feedback about their risk category for type 2 diabetes and for hypertension, based on their screening results. Logistic regression will test the hypothesized model for predicting type 2 diabetes.

The preliminary mean self-reported birth weight is 6.7 pounds, with a range from 2.25 to 12.0 pounds. So far, it appears that women with type 2 diabetes (cases) are now heavier than the controls, have a wider waist measure, and were heavier at age 25 years.

Study enrollment has been completed. We are now gathering official birth weight data. In addition, we are asking participants to contact us to verify the birth weight they reported at enrollment to see if they can give us the most accurate birth weight they have learned from documents, family members, or other sources.

Implications: If this study validates the theory that being born small, with the onset of abdominal obesity later in life, puts one at increased risk for developing type 2 diabetes, then targeted public health interventions can be designed that lead to a decreased incidence of type 2 diabetes in African American women. In addition, this study will contribute to a fuller understanding of the relationship between type 2 diabetes and abdominal obesity for a wide range of birthweights in this population.

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For more information, contact B. Michelle Harris

Last updated: 03/13/2009