Variation in nutrient intakes by ethnicity: results from the Study of Women's Health Across the Nation (SWAN)

Objective: To use food frequency questionnaires to summarize the macro- and micronutrient intakes of women of diverse ethnicity in the Study of Women's Health Across the Nation. Design: The Study of Women's Health Across the Nation is a multisite, multiethnic, community-based, longitudinal study of midlife women at seven geographic locations in the USA. The cohort is made up of participants with African, Caucasian, Chinese, Hispanic, and Japanese ethnic backgrounds. The Block Food Frequency Questionnaire was modified to accommodate ethnic-specific diets and was administered by interview. Descriptive statistics for macro- and micronutrient intakes were calculated, and variation in nutrient intakes by ethnic group was assessed using multivariable models, with Bonferonni correction for multiple comparisons. Results: The crude and energy-adjusted distributions of all 28 nutrients studied differed statistically by ethnicity (p < 0.001). In many cases the magnitude of the variation was small. For example, the difference between the highest and lowest mean energy intakes was approximately 135 kcal (African American vs. Hispanic). Other differences were substantial: the energy-adjusted total fat intake in Chinese women was at least 10% lower than all other ethnic groups except the Japanese women (all pair-wise comparisons; p < 0.01). Conclusions: Knowledge of variation in nutrient intake is critical to the understanding of how diet and health are related. The broad range of nutrient intakes reported by these participants will permit exploration of the associations between diet, menopause, and health and consideration of the role of dietary factors in explaining health-related differences among women of diverse ethnicity.