Vitamins don't slow development of cardiovascular disease in high-risk women

American Heart Association Scientific Sessions Late-Breaking News:

CHICAGO, Nov. 13 -- Antioxidant vitamins and folic acid didn't slow the development of cardiovascular disease among high-risk women in two long-running, randomized trials, researchers reported today at the American Heart Association's Scientific Sessions 2006.

Results of the Women's Antioxidant and Folic Acid Cardiovascular Study (WAFACS) were presented today in a late-breaking clinical trials session. 

"Our study does not suggest that taking folic acid, B6 or B12 primarily to prevent cardiovascular disease (CVD) would be worthwhile.  Women who are taking them solely for that purpose may want to discontinue," said Christine M. Albert, M.D., M.P.H., lead author of the study and director of the Center for Arrhythmia Prevention at Brigham and Women's Hospital, in Boston, Mass.

Researchers found no adverse effects from the vitamins but said there are other important non-cardiac reasons to take them including during pregnancy, when a woman's nutritional needs are higher.  Folic acid supplementation has been associated with reducing birth defects of the brain and spinal cord.

WAFACS is a randomized, placebo-controlled study of folic acid and other B vitamins in a subset of 5,442 women participating in a larger trial called Women's Antioxidant Cardiovascular Study (WACS).  WACS is a randomized, placebo-controlled trial of antioxidant vitamins with 8,171 females.  Participants were health professionals over age 40 who either had a history of CVD or were considered at high risk due to three or more CVD risk factors such as high blood pressure, high cholesterol levels, diabetes and smoking.

Researchers compared the effects of a combination of folic acid (2.5 milligrams daily), vitamin B6 (50 mg daily) and vitamin B12 (1 mg daily) versus placebo in reducing risk of major vascular events including coronary heart disease, heart attack and stroke.  Researchers tracked the women for 7.3 years and checked for heart attacks, strokes, coronary revascularization procedures and cardiovascular-related deaths.

They found that women taking the vitamin/folic acid combination were just as likely to suffer a major vascular event.

Researchers also investigated whether decreasing homocysteine levels from folic acid supplementation would be associated with reductions in CVD events.  Homocysteine levels increase with advancing age, kidney disease and other well-documented cardiovascular risk factors.

Some studies have associated elevated blood levels of homocysteine, a by-product of protein metabolism, with increased risk of CVD.  But it is unknown whether homocysteine is a risk factor or a marker of pre-existing cardiovascular disease.  This study seems to support that it is a marker, Albert said.

In the antioxidant vitamin trial, WACS, researchers found no cardiovascular benefits from three antioxidants - vitamin C, vitamin E or beta-carotene - on the primary end point of CVD during 9.4 years of follow-up, said JoAnn Manson, M.D., Dr. P.H., chief of the Division of Preventive Medicine at Brigham and Women's Hospital in Boston, Mass., and the Elizabeth F. Brigham Professor of Women's Health at Harvard Medical School.

While earlier randomized trials had failed to find evidence that antioxidants were beneficial for CVD, WACS was the first to examine the effect of vitamin C alone on the risk of CVD.

In pre-specified subgroup analyses of WACS, women who were randomized to the vitamin C group and who smoked or who had three or more risk factors but did not have prevalent CVD seemed at reduced risk of stroke.  Those with prior CVD who took vitamin E also had a significant reduction in cardiovascular events.

Although those findings may have been due to chance, they warrant further investigation, the researchers said.

Albert's co-authors include: Nancy R. Cook, Sc.D.; J. Michael Gaziano, M.D.; Shari S. Bassuk, Sc.D.; Elaine Zaharris, B.A.; Jean G. MacFayden, B.A.; Eleanor Danielson, M.I.A.; Martin Van Denburgh, B.A.; Julie E. Buring, Sc.D; and JoAnn E. Manson, M.D., Dr.P.H.

Manson's co-authors include: Christine M. Albert, M.D., M.P.H.; Nancy R. Cook, Sc.D.; J. Michael Gaziano, M.D.; Shari S. Bassuk, Sc.D.;  Elaine Zaharris, B.A.; Jean G. MacFayden, B.A.; Eleanor Danielson, M.I.A.; Martin Van Denburgh, B.A.; and Julie E. Buring, Sc.D.

The National Heart, Lung, and Blood Institute (NHLBI) funded the study.

Statements and conclusions of abstracts presented at American Heart Association scientific meetings are solely those of the authors and do not necessarily reflect association policy or position.  The American Heart Association makes no representation or warranty as to their accuracy or reliability.

NR06 - 1120 (SS06/Albert/WAFACS)

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Note: Presentation time is 11:45 a.m. CST, Monday, Nov. 13.