Dietary Glycemic Load, Glycemic Index, and Associated Factors in a Multiethnic Cohort of Midlife Women

Abstract

Background: Dietary glycemic load (GL) and glycemic index (GI), indicators of the postprandial glucose and insulin response to carbohydrate composition of diet, have been suggested as independent risk factors for cardiovascular disease and diabetes. However, current knowledge about the distribution, correlates, and major contributors of these measures in human populations is limited.

Objective: To describe the intakes and correlates of GL and GI in African American, Caucasian, Chinese, and Japanese women in the Study of Women's Health Across the Nation (SWAN).

Design: Data are from 2025 women participating in SWAN, a multi-ethnic, community-based cohort study of women transitioning into menopause. GL and GI were estimated from dietary information obtained in the fifth year of the study using a modified Block food frequency questionnaire. The relationship of GL and GI to dietary factors and selected demographic measures, including race/ethnicity and lifestyle factors, was examined using bivariate and multivariate analyses.

Results: GI and GL were consistently lower in Caucasian women than in African American, Japanese, or Chinese women. Education was inversely associated with GL and alcohol consumption was inversely associated with GI among all ethnic groups. The association between family income and glycemic measures varied across ethnic groups. GI was positively associated with consumption of grains and potatoes and inversely associated with consumption of fruits, juices, dairy foods, protein sources, and sweets among all ethnic groups.

Conclusions: It is important for researchers to consider factors such as ethnicity, family income, and alcohol intake as potential confounders when investigating the associations of GL and GI with disease.

The Study of Women's Health Across the Nation (SWAN) has received grant support from the National Institutes of Health, Department of Health and Human Services, through the National Institute on Aging, the National Institute of Nursing Research, and the NIH Office of Research on Women's Health (grants NR004061, AG012505, AG012535, AG012531, AG012539, AG012546, AG012553, AG012554, AG012495). The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the NIA, NINR, ORWH, or the NIH.

We thank the study staff at each site and all the women who participated in SWAN:

Clinical Centers: University of Michigan, Ann Arbor: MaryFran Sowers, PI; Massachusetts General Hospital, Boston, MA: Robert Neer, PI 1994–1999, Joel Finkelstein, PI 1999–present; Rush University, Rush University Medical Center, Chicago, IL: Lynda Powell, PI; University of California, Davis/Kaiser: Ellen Gold, PI; University of California, Los Angeles: Gail Greendale, PI; University of Medicine and Dentistry, New Jersey Medical School, Newark: Gerson Weiss, PI 1994–2004, Nanette Santoro, PI 2004–present; and the University of Pittsburgh, Pittsburgh, PA: Karen Matthews, PI.

NIH Program Office: National Institute on Aging, Bethesda, MD: Marcia Ory, 1994–2001, Sherry Sherman, 1994–present; National Institute of Nursing Research, Bethesda, MD: Program Officers.

Central Laboratory: University of Michigan, Ann Arbor: Daniel McConnell (Central Ligand Assay Satellite Services).

Coordinating Center: New England Research Institutes, Watertown, MA: Sonja McKinlay, PI 1995–2001; University of Pittsburgh, Pittsburgh, PA: Kim Sutton-Tyrrell, PI 2001–present.

Steering Committee: Chris Gallagher, Chair; Susan Johnson, Chair.