title: Effects of the National Cholesterol Education Program's Step I and Step II dietary intervention programs on cardiovascular disease risk factors: a meta-analysis.
abstract: BACKGROUND
  Plasma lipid and lipoprotein responses have been variable in dietary intervention studies.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the effects of the National Cholesterol Education Program's Step I and Step II dietary interventions on major cardiovascular disease risk factors using meta-analysis.
  
  
  METHODS
  MEDLINE was used to select 37 dietary intervention studies in free-living subjects published from 1981 to 1997.
  
  
  RESULTS
  Step I and Step II dietary interventions significantly decreased plasma lipids and lipoproteins. Plasma total cholesterol (TC), LDL cholesterol, triacylglycerol, and TC:HDL cholesterol decreased by 0.63 mmol/L (10%), 0.49 mmol/L (12%), 0.17 mmol/L (8%), and 0.50 (10%), respectively, in Step I intervention studies, and by 0.81 mmol/L (13%), 0.65 mmol/L (16%), 0.19 mmol/L (8%), and 0.34 (7%), respectively, in Step II intervention studies (P < 0.01 for all). HDL cholesterol decreased by 7% (P = 0.05) in response to Step II but not to Step I dietary interventions. Positive correlations between changes in dietary total and saturated fatty acids and changes in TC and LDL and HDL cholesterol were observed (r = 0.59, 0.61, and 0.46, respectively; P < 0.001). Multiple regression analyses showed that for every 1% decrease in energy consumed as dietary saturated fatty acid, TC decreased by 0.056 mmol/L and LDL cholesterol by 0.05 mmol/L. Moreover, for every 1-kg decrease in body weight, triacylglycerol decreased by 0.011 mmol/L and HDL cholesterol increased by 0.011 mmol/L. Exercise resulted in greater decreases in TC, LDL cholesterol, and triacylglycerol and prevented the decrease in HDL cholesterol associated with low-fat diets.
  
  
  CONCLUSIONS
  Step I and Step II dietary interventions have multiple beneficial effects on important cardiovascular disease risk factors.
authors: Graduate Program in Nutrition, The Pennsylvania State University, University Park, USA.
authors: S
authors: S
authors: Yu-Poth
authors: G
authors: G
authors: Zhao
authors: T
authors: T
authors: Etherton
authors: M
authors: M
authors: Naglak
authors: S
authors: S
authors: Jonnalagadda
authors: P M
authors: PM
authors: Kris-Etherton
mesh_terms: D001835:Body Weight; D002318:Cardiovascular Diseases / Q000209:etiology / Q000517:prevention & control*; D002784:Cholesterol / Q000097:blood; D018752:Diet, Fat-Restricted; D015444:Exercise; D006266:Health Education; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000178:diet therapy* / Q000628:therapy; D008055:Lipids / Q000097:blood; D012044:Regression Analysis; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood
chemical_list: D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol