Diet, lipoproteins and the progression of coronary atherosclerosis. The Leiden Intervention Trial

The relationship between diet, serum lipoproteins, and the progression of coronary lesions was studied in 39 patients with stable angina pectoris in whom coronary arteriography had shown at least 1 vessel with 50% obstruction before intervention. Intervention consisted of a 2-year vegetarian diet that had a ratio of polyunsaturated to saturated fatty acids of at least 2.0, and that contained less than 100mg of cholesterol per day. Dietary changes were associated with a significant increase in linoleic acid content of cholesterol esters and a significant lowering of bodyweight, systolic blood pressure, serum total cholesterol, and the ratio of total to high density lipoprotein (total/HDL) cholesterol. Angiographic examination was performed after 24 months; angiograms were assessed visually (with blinding) and by computer-assisted image analysis. Both types of assessment indicated progression of disease in 21 of 39 patients but no lesion growth in 18. Coronary lesion growth correlated with total/HDL cholesterol (r = 0.50, p = 0.001) but not with blood pressure, smoking status, alcohol intake, weight, or drug treatment. Disease progression was significant in patients who had values for total/HDL cholesterol that were higher than the median (greater than 6.9) throughout the trial period. No coronary lesion growth was observed in patients who had lower values for total/HDL cholesterol (less than 6.9) throughout the trial or who initially had higher values (greater than 6.9) that were significantly lowered by dietary intervention.