Background: A premise of the 2005 Dietary Guidelines for Americans (DGA) is chronic disease prevention.
Objective: The goal was to determine whether a diet meeting the DGA is associated with less atherosclerotic lesion progression.
Design: We used the data from 224 postmenopausal women with established coronary artery disease enrolled in the Estrogen Replacement and Atherosclerosis Study. Atherosclerosis progression was defined by repeated measures of quantitative angiography over a 3-y period. Adherence to the key DGA recommendations was measured by using the DGA Adherence Index (DGAI; possible range: 0-20), with each component weighted equally, and the modified DGAI score (wDGAI; possible range: -0.19-0.51), with each component weighted based on its relation to atherosclerosis progression. Mixed-model regression analyses were performed to assess the association between diet and atherosclerosis progression.
Results: No women consumed a diet meeting all of the DGA recommendations. The mean (range) of the DGAI score was 14.1 (8.0-19.0). DGAI was not associated with atherosclerosis progression (P = 0.44), whereas wDGAI was inversely associated; a 1-SD difference in wDGAI was related to 0.049-mm less narrowing of the coronary arteries (SE = 0.017, P = 0.004).
Conclusions: In postmenopausal women with established heart disease, under the assumption that all DGA recommendations are similarly effective, overall adherence was not associated with atherosclerosis progression. However, assigning differential weights to the DGA recommendations, the adherence was significantly associated with slower atherosclerosis progression. Assuming equity of associations between all dietary recommendations and disease outcomes is a limitation in accurately examining the effectiveness of the DGA.