Ethnic Differences in Obesity and Surgical Weight Loss between African-American and Caucasian Females

Background: In the general population, African-American females are more obese and resistant to weight loss than Caucasian women. In the present study, we examined the severity of obesity among morbidly obese African-American and Caucasian females, studied the effectiveness of Roux-en-Y gastric bypass (RYGBP), and sought to identify factors contributing to obesity and weight loss. Methods: The study population included 153 morbidly obese females randomly selected from our general bariatric patient population. Anthropometric measurements consisted of body weight, body mass index (BMI), excess weight, and waist, hip, thigh, and neck circumferences. Factors that may contribute to obesity included age, age of obesity onset, number of childbirths, calorie intake, diet composition, and degree of psychological distress. The effects of RYBGP were studied in weight-matched groups of African-American and Caucasian females (n=37 per group) at weight loss nadir, i.e. 12 to 18 months after surgery. Results: We found that morbid obesity is more severe among African-American than Caucasian females. The greater degree of obesity of African-American, as compared to Caucasian, females is not due to ethnic differences in calorie intake, diet composition, age or age of obesity onset, number of childbirths, and psychological distress. RYGBP is less effective in reducing body fat and, consequently, excess body weight of the African-American than the Caucasian females, suggesting possible ethnic differences in fat metabolism. Conclusion: African-American females with morbid obesity have greater adiposity than do Caucasian women and lose significantly less body fat after RYGBP.