Date of Award

2005

Degree Type

Thesis

Degree Name

Master of Science in Nutrition and Food Science

Department

Nutrition and Food Sciences

First Advisor

Geoffrey Greene

Abstract

Background: Data suggest that African Americans lose less weight and show fewer improvements in cardiovascular diseases such as blood pressure following gastric bypass surgery (GBP).

Objective: The purpose of this study was to describe differences in weight loss between Caucasian and African American patients following GBP and to identify if these differences are related to dietary intake. This study also sought to identify differences in blood pressure and serum lipid levels between African Americans and Caucasians after GBP.

Methods and Subjects: This was a retrospective database review of a sample of 84 adult patients, 24 African American and 60 Caucasian women and men between the ages of 33 and 53 years. All subjects had GBP surgery in 2001 at the Bariatric Surgery Program at Boston Medical Center (BMC) in Boston, MA and were followed for one year postoperatively. Patients were excluded if weight data were missing at baseline, three months and one year following GBP. A total of 9 African Americans and 41 Caucasians provided data at all three time points and were included in the study. Weight change was calculated using percent of initial body weight and change in body mass index (BMI). Differences in dietary intake were determined using dietary records completed by the patients or by patient dietary recalls collected by the dietitian. Blood pressure, total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglyceride levels at baseline and one year were abstracted from the GBP database.

Results: There were no differences in baseline characteristics between African Americans and Caucasians. Caucasians lost more weight (BMI reduced from 56 ± 12 to 34 ± 8 at one year after surgery with a percent weight loss of 38±8) than African Americans (BMI reduced from 54 ± 8 to 40 ± 11 with a percent weight loss of 26 ± 10) (p < .001). There were main effects for time and race on weight loss expressed as change in BMI and percent weight loss at one year following GBP (p < .001) as well as an interaction between and within race weight loss (p < .001). There were no differences between races for diet, blood pressure, or serum lipids. However, there were differences within race for each of these variables (p < .05).

Conclusions: These data demonstrate that GBP promotes significant weight loss among morbidly obese African Americans and Caucasians. African Americans lost less weight at one year after GBP; however, dietary parameters and cardiovascular risk indices were not significantly different between races. Prospective intervention studies should be conducted to help clarify the primary etiologies for differential weight loss between races following GBP. Identification of these causes will help delineate specific interventions that are sensitive to racial differences, and ultimately optimize the outcome of bariatric surgery in an ethnically diverse patient population.

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