Women experience as much illness from hardening of the arteries including stroke and heart disease as do men, but because women experience them later in life, the importance of heart disease, cholesterol, and diet for women has been under appreciated. The proposed study is a dietary intervention trial to test the lipid lowering response to the NCEP Step Two Diet by free-living hyperlipidemic women and men and to compare the response between them. Subjects will be employees of the Boeing Company in the Seattle area, who have two separate measurements of low density lipoprotein cholesterol (LDL-C) which are at or above the age- sex- specific 75th percentile value, are not taking lipid altering medications, and are not already on a diet more restrictive than the study diet. Subjects win be further classified as being hypercholesterolemic (HC), only LDL-C is elevated, or combined hyperlipidemic (CHL), both LDL-C and total triglyceride are elevated. Half of the subjects will be randomized to diet instruction with 2 years of follow-up and half to 6 months of no intervention followed by the same diet instruction and followup. Control subjects will have a fasting blood draw at 3 months of the nonintervention period. Having parallel intervention and control groups is necessary to test the efficacy of the NCEP Step Two Diet: The diet will be taught to study subjects during 8 weekly 2 hour classes. Follow-up will include 4 individual visits, at 3, 6, 9, and 12 months, with a dietitian and 2 group sessions, at 4.5 and 10.5 months, in the first year and 2 individual visits, at 18 and 24 months, in the second year. Fasting blood samples for lipoprotein lipid analysis and 4-day food diaries will be collected at all individual visits. Additionally, medical history, lifestyle characteristics, vital signs, other adherence measures, behavioral factors related to adherence, and serum nutrients for monitoring nutrient sufficiency will be collected. Dietitians will provide adherence and dietary modification counseling as necessary to help participants maximize their adherence. The primary questions to be answered are: 1) Does the NCEP Step Two Diet effectively lower plasma lipids in HC and CHL women and men over 6 months? 2) Do HC and CHL women have a different response than HC and CHL men? 3) Is response in women influenced by menstrual status and sex hormone exposure?, and 4) Are the behavioral adaptations to dietary modification different between women and men?
|Knopp, R H; Retzlaff, B; Walden, C et al. (2000) One-year effects of increasingly fat-restricted, carbohydrate-enriched diets on lipoprotein levels in free-living subjects. Proc Soc Exp Biol Med 225:191-9|
|Retzlaff, B M; Walden, C E; McNeney, W B et al. (1997) Nutritional intake of women and men on the NCEP Step I and Step II diets. J Am Coll Nutr 16:52-61|
|Retzlaff, B M; Dowdy, A A; Walden, C E et al. (1997) The Northwest Lipid Research Clinic Fat Intake Scale: validation and utility. Am J Public Health 87:181-5|