Low-Fat Dietary Pattern and Risk of Cardiovascular Disease: The Women's Health Initiative Randomized Controlled Dietary Modification Trial | Cancer Screening, Prevention, Control | JAMA | JAMA Network
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Original Contribution
February 8, 2006

Low-Fat Dietary Pattern and Risk of Cardiovascular Disease: The Women's Health Initiative Randomized Controlled Dietary Modification Trial

Author Affiliations

Author Affiliations: MedStar Research Institute/Howard University, Washington, DC (Dr Howard); Northwestern University, Chicago/Evanston, Ill (Drs Horn and Greenland); George Washington University, Washington, DC (Dr Hsia); Brigham and Women's Hospital, Harvard Medical School, Boston, Mass (Dr Manson); Stanford Prevention Research Center, Stanford, Calif (Dr Stefanick); Albert Einstein College of Medicine, Bronx, NY (Dr Wassertheil-Smoller); University of Pittsburgh, Pittsburgh, Pa (Dr Kuller); Fred Hutchinson Cancer Research Center, Seattle, Wash (Drs LaCroix, Prentice, Tinker, Anderson, and Beresford); University of California at San Diego (Dr Langer); University of Medicine and Dentistry of New Jersey, Newark (Dr Lasser); University of Alabama at Birmingham (Dr Lewis); University of Florida, Gainesville (Drs Limacher and Perri); University of Minnesota, Minneapolis (Dr Margolis); The Ohio State University, Columbus (Dr Mysiw); University of Massachusetts/Fallon Clinic, Worcester (Dr Ockene); University of Miami, Miami, Fla (Dr Parker); Emory University, Atlanta, Ga (Dr Phillips); University of California at Davis (Dr Robbins); National Heart, Lung, and Blood Institute, Bethesda, Md (Dr Rossouw); University of Wisconsin, Madison (Dr Sarto); University of Hawaii, Honolulu (Dr Schatz); University of Iowa, Iowa City/Davenport (Dr Snetselaar); Kaiser Permanente Center for Health Research, Portland, Ore (Dr Stevens); University at Buffalo, Buffalo, NY (Dr Trevisan); Wake Forest University School of Medicine, Winston-Salem, NC (Dr Vitolins); Brown University, Providence, RI (Dr Assaf); University of Arizona, Tucson/Phoenix (Dr Bassford); Rush University Medical Center, Chicago (Dr Black); University of Nevada, Reno (Dr Brunner); University of Texas Health Science Center, San Antonio (Dr Brzyski); Kaiser Permanente Division of Research, Oakland, Calif (Dr Caan); Harbor-UCLA Research and Education Institute, Torrance, Calif (Dr Chlebowski); University of Cincinnati, Cincinnati, Ohio (Dr Gass); State University of New York at Stony Brook (Dr Granek); Baylor College of Medicine, Houston, Tex (Dr Hays); University of California at Los Angeles (Dr Heber); University of North Carolina, Chapel Hill (Dr Heiss); Wayne State University School of Medicine/Hutzel Hospital, Detroit, Mich (Dr Hendrix); University of California at Irvine (Dr Hubbell); University of Tennessee Health Science Center, Memphis (Dr Johnson); and Medical College of Wisconsin, Milwaukee (Dr Kotchen). Dr Assaf is now affiliated with Pfizer Inc, Cambridge, Mass.

JAMA. 2006;295(6):655-666. doi:10.1001/jama.295.6.655

Context Multiple epidemiologic studies and some trials have linked diet with cardiovascular disease (CVD) prevention, but long-term intervention data are needed.

Objective To test the hypothesis that a dietary intervention, intended to be low in fat and high in vegetables, fruits, and grains to reduce cancer, would reduce CVD risk.

Design, Setting, and Participants Randomized controlled trial of 48 835 postmenopausal women aged 50 to 79 years, of diverse backgrounds and ethnicities, who participated in the Women's Health Initiative Dietary Modification Trial. Women were randomly assigned to an intervention (19 541 [40%]) or comparison group (29 294 [60%]) in a free-living setting. Study enrollment occurred between 1993 and 1998 in 40 US clinical centers; mean follow-up in this analysis was 8.1 years.

Intervention Intensive behavior modification in group and individual sessions designed to reduce total fat intake to 20% of calories and increase intakes of vegetables/fruits to 5 servings/d and grains to at least 6 servings/d. The comparison group received diet-related education materials.

Main Outcome Measures Fatal and nonfatal coronary heart disease (CHD), fatal and nonfatal stroke, and CVD (composite of CHD and stroke).

Results By year 6, mean fat intake decreased by 8.2% of energy intake in the intervention vs the comparison group, with small decreases in saturated (2.9%), monounsaturated (3.3%), and polyunsaturated (1.5%) fat; increases occurred in intakes of vegetables/fruits (1.1 servings/d) and grains (0.5 serving/d). Low-density lipoprotein cholesterol levels, diastolic blood pressure, and factor VIIc levels were significantly reduced by 3.55 mg/dL, 0.31 mm Hg, and 4.29%, respectively; levels of high-density lipoprotein cholesterol, triglycerides, glucose, and insulin did not significantly differ in the intervention vs comparison groups. The numbers who developed CHD, stroke, and CVD (annualized incidence rates) were 1000 (0.63%), 434 (0.28%), and 1357 (0.86%) in the intervention and 1549 (0.65%), 642 (0.27%), and 2088 (0.88%) in the comparison group. The diet had no significant effects on incidence of CHD (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.90-1.06), stroke (HR, 1.02; 95% CI, 0.90-1.15), or CVD (HR, 0.98; 95% CI, 0.92-1.05). Excluding participants with baseline CVD (3.4%), the HRs (95% CIs) for CHD and stroke were 0.94 (0.86-1.02) and 1.02 (0.90-1.17), respectively. Trends toward greater reductions in CHD risk were observed in those with lower intakes of saturated fat or trans fat or higher intakes of vegetables/fruits.

Conclusions Over a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVD risk.

Clinical Trials Registration ClinicalTrials.gov Identifier: NCT00000611