The Minnesota Coronary Survey was a 4.5-year, open enrollment, single end-time, double-blind, randomized clinical trial that was conducted In six Minnesota state mental hospitals and one nursing home. It Involved 4393 Institutionalized men and 4664 Institutionalized women. The trial compared the effects of a 39% fat control diet (18% saturated fat, 5% polyunsaturated fat, 16% monounsaturated fat, 446 mg dietary cholesterol per day) with a 38% fat treatment diet (9% saturated fat, 15% polyunsaturated fat, 14% monounsaturated fat, 166 mg dietary cholesterol per day) on serum cholesterol levels and the Incidence of myocardlal Infarctions, sudden deaths, and all-cause mortality. The mean duration of time on the diets was 384 days, with 1568 subjects consuming the diet for over 2 years. The mean serum cholesterol level In the pre-admission period was 207 mg/dl, falling to 175 mg/dl in the treatment group and 203 mg/dl In the control group. For the entire study population, no differences between the treatment and control groups were observed for cardiovascular events, cardiovascular deaths, or total mortality. A favorable trend for all these end-points occurred In some younger age groups. (Arteriosclerosis 9:129-135, January/February 1989) T he institutions chosen for the trial were the Minnesota state mental hospitals at Anoka, Fergus Falls, Hastings, Moose Lake, St. Peter, and Willmar and the nursing home at Oak Terrace. Before initiation of the experimental phase, the populations were observed for a 3-year period, during which their suitability for a long-term dietary trial was studied. The feeding program began in the Willmar State Hospital in November, 1968. The program was phased in to the other institutions in succession over the following 15 months. The trial was an outgrowth of the National Diet-Heart Feasibility Study. 1 Methods Ethical ConsiderationsThe project was approved by the Clinical Research Committee of the University and, after extensive discussion with the relevant institutional committees, by each of the collaborating hospitals. No consent forms were required on the grounds that the two diets were both acceptable as house diets and the tests all contributed to better patient care. Before initiation of the study in each hospital, all the residents and staff were invited to a meeting at which the investigators explained the project. Samples of the foods were served at these meetings. There was a question and Received March 25,1987; revision accepted August 30,1988. answer period, and the residents were invited to make appointments for one-to-one further explanations if they wished. They were allowed to decline to participate or to discontinue their participation at any time. Nonparticipants were served the control diet, which was similar to the pre-study institutional diets. Blood was not drawn from nonparticipants, and electrocardiograms were not recorded. Participation was nearly 100% with fewer than a dozen refusals throughout the trial. Experimental PlanThe original population was initially ...

Preliminary data from the Multiple Risk Factor Intervention Trial (MRFIT) have been examined for evidence that the program has an influence on plasma HDL-cholesterol. The overall mean level of this lipoprotein in the initial cohort of 1,084 men was not altered by two years of participation in this risk factor reduction project. However, changes did occur, both upwards and downwards, in some individuals. There were significant negative associations between change in HDL-cholesterol and changes in body mass, VLDL-cholesterol, LDL-cholesterol, and serum thiocyanate (a measure of cigarette smoking exposure); and there was a small positive association with change in reported alcohol intake. Multiple regression analysis revealed each of these associations to be independent of the others. The fat-controlled diet designed to lower total serum cholesterol did not decrease HDL-cholesterol levels. We conclude that conventional risk reduction programs are not likely to lower circulating HDL-cholesterol, and that program components such as weight reduction and smoking cessation may increase the levels.