A low-fat dietary pattern and risk of metabolic syndrome in postmenopausal women: The Women's Health Initiative

Objective: Nutrition plays an important role in metabolic syndrome etiology. We examined whether the Women's Health Initiative (WHI) Dietary Modification Trial influenced metabolic syndrome risk. Materials/Methods: 48,835 postmenopausal women aged 50-79 years were randomized to a low-fat (20% energy from fat) diet (intervention) or usual diet (comparison) for a mean of 8.1 years. Blood pressure, waist circumference and fasting blood measures of glucose, HDL-cholesterol and triglycerides were measured on a subsample (n = 2816) at baseline and years 1, 3 and 6 post-randomization. Logistic regression estimated associations of the intervention with metabolic syndrome risk and use of cholesterol-lowering and hypertension medications. Multivariate linear regression tested associations between the intervention and metabolic syndrome components. Results: At year 3, but not years 1 or 6, women in the intervention group (vs. comparison) had a non-statistically significant lower risk of metabolic syndrome (OR = 0.83, 95%CI 0.59-1.18). Linear regression models simultaneously modeling the five metabolic syndrome components revealed significant associations of the intervention with metabolic syndrome at year 1 (p < 0.0001), but not years 3 (p = 0.19) and 6 (p = 0.17). Analyses restricted to intervention-adherent participants strengthened associations at years 3 (p = 0.05) and 6 (p = 0.06). Cholesterol-lowering and hypertension medication use was 19% lower at year 1 for intervention vs. comparison group women (OR = 0.81, 95% CI 0.60-1.09).Over the entire trial, fewer intervention vs. comparison participants used these medications (26.0% vs. 29.9%), although results were not statistically significant (p = 0.89). Conclusions: The WHI low-fat diet may influence metabolic syndrome risk and decrease use of hypertension and cholesterol-lowering medications. Findings have potential for meaningful clinical translation.