Researchers at Rush University Medical Center in Chicago followed 2017 women whose average age was approximately 46 years old from Chicago, Detroit, Boston and Pittsburgh for four years as part of the Study of Women Health Across the Nation (SWAN).
"The study was designed to test the effects of race and socioeconomic status on BMI by examining a diverse group of women," said Tené Lewis, PhD, psychologist in the Rush department of preventive medicine and lead researcher on this study. Lewis said that African American women are disproportionately represented among the overweight and obese but researchers are not sure whether race, socioeconomic status, or a combination of both, contribute to this.
According to a study published in the Journal of the American Medical Association in 2002, approximately half of African-American females are obese while about 30 percent of Caucasian females are considered obese.
Lewis and her colleagues found that, while women of both races with only high school education had similar BMI levels (31.4 for blacks versus 31.1 for whites) the BMIs of Caucasian women with college education were lower than the BMIs of similar African American women (30.7 versus 27.1). Because women of both races in all educational levels gained equally over time, the absolute level differences observed at baseline persisted over the four-year follow up, she said.
These findings suggest that middle or high socioeconomic status may exert a more protective effect on BMI for Caucasian women compared to their African American peers, Lewis said. She indicated that the results of this study are provocative and will lead to further research that examines why college education is not as protective against obesity among black women. Lewis controlled for other confounding factors such as age, menopausal status, smoking, chronic health conditions, physical activity, total caloric intake, percent fat intake and stressful life events.
"Given that increases did not differ by race or SES over time women, these race SES patterns may be set in place and well established before midlife," she said.
SWAN is a multi-site longitudinal, epidemiologic study designed to examine the health of women during their middle years. The study examines the physical, biological, psychological and social changes during this transitional period. The goal of SWAN's research is to help scientists, health care providers and women learn how mid-life experiences affect health and quality of life during aging. The study is co-sponsored by the National Institute on Aging (NIA), the National Institute of Nursing Research (NINR), the National Institutes of Health (NIH), Office of Research on Women's Health, and the National Center for Complementary and Alternative Medicine.