Chapter 7. Relation of changes in dietary lipids and weight, trial years 1-6, to changes in blood lipids in the special intervention and usual care groups in the Multiple Risk Factor Intervention Trial

For men in the special intervention (SI) group of the Multiple Risk Factor Intervention Trial, the average decrease in serum total cholesterol was 16.9 mg/dL (6.7%); for men in the usual care (UC) group, the average decrease was 9.7 mg/dL (3.8%). The difference between the two groups for plasma total cholesterol was 6.2 mg/dL. Plasma low-density-lipoprotein (LDL) cholesterol decreased 10.6 mg/dL (6.6%) in SI men and 5.4 mg/dL (3.4%) in UC men. Mean weight losses were 3.0 lb (1.36 kg) and 0.1 lb (0.05 kg) for SI and UC men, respectively. Change in blood total cholesterol was directly related to baseline concentration; for men with serum total cholesterol ≤ 220 mg/dL, those in the SI group decreased their total cholesterol by 7.8% (design goal: 10%) and those in the UC group by 4.8% (expected: 0%). Change in dietary lipid intake (summarized by the Keys score) for SI men was significantly related to changes in blood total cholesterol, LDL cholesterol, and triglyceride, but not to change in high-density-lipoprotein (HDL) cholesterol. Controlled for weight change, coefficients for Keys score change were smaller but remained significantly related to each blood lipid except HDL cholesterol. Weight loss was associated with favorable effects on all blood lipids. Influences of change in diet and weight on blood lipids were quantitatively less for hypertensive men for serum total cholesterol, HDL cholesterol, and triglyceride than for nonhypertensive men. Nonsmokers had greater decreases than smokers in blood total cholesterol, LDL cholesterol, and triglyceride.