Dietary patterns, insulin resistance, and prevalence of the metabolic syndrome in women.

BACKGROUND Although individual foods and nutrients have been associated with the metabolic syndrome, whether dietary patterns identified by factor analysis are also associated with this syndrome is not known. OBJECTIVE We aimed to evaluate the association of major dietary patterns characterized by factor analysis with insulin resistance and the metabolic syndrome among women. DESIGN Usual dietary intakes were assessed in a cross-sectional study of 486 Tehrani female teachers aged 40-60 y. Anthropometric and blood pressure measurements were performed, and fasting blood samples were taken for biomarker assessment. The metabolic syndrome was defined according to Adult Treatment Panel III guidelines, and insulin resistance was defined as the highest quartile of the homeostasis model assessment scores. RESULTS We identified 3 major dietary patterns by factor analysis: the healthy dietary pattern, the Western dietary pattern, and the traditional dietary pattern. After control for potential confounders, subjects in the highest quintile of healthy dietary pattern scores had a lower odds ratio for the metabolic syndrome (odds ratio: 0.61; 95% CI: 0.30, 0.79; P for trend < 0.01) and insulin resistance (0.51; 0.24, 0.88; P for trend < 0.01) than did those in the lowest quintile. Compared with those in the lowest quintile, women in the highest quintile of Western dietary pattern scores had greater odds for the metabolic syndrome (1.68; 1.10, 1.95; P for trend < 0.01) and insulin resistance (1.26; 1.00, 1.78; P for trend < 0.01). Higher consumption of traditional dietary pattern was significantly associated only with abnormal glucose homeostasis (1.19; 1.04, 1.59; P < 0.05). CONCLUSION Significant associations exist between dietary patterns identified by factor analysis, the metabolic syndrome, and insulin resistance.