Antioxidant Vitamin Therapy: To 'E' or not to 'E' JoAnn E. Manson, MD, DrPH Chief, Division of Preventive Medicine Brigham and Women's Hospital Professor of Medicine Harvard Medical School State of the Art Lecture

ROAD MAP Biological Mechanisms Animal Studies Human Observational Studies Randomized Clinical Trials Conclusions

CAUSES OF DEATH IN THE UNITED STATES National Center for Health Statistics, Heart Disease 31.6% Cerebrovascular Disease 9.4% Other 27.5% Cancer 23.4% Respiratory Diseases 8.1% Cardiovascular Disease 41%

HYPOTHESIZED ANTIATHEROGENIC MECHANISMS OF ANTIOXIDANT VITAMINS Antioxidant vitamins can inhibit the oxidation and/or uptake of LDL cholesterol. Oxidized LDL is the particularly atherogenic form of cholesterol.

ROLE OF OXIDIZED-LDL IN ATHEROSCLEROSIS Endothelial damage Monocyte/macrophage recruitment Increased uptake of LDL by foam cell Alteration in vascular tone Induction of growth factors Formation of autoantibodies to oxidized LDL

HYPOTHESIZED ANTICANCER MECHANISMS OF ANTIOXIDANT VITAMINS Antioxidant vitamins may prevent tissue damage by trapping organic free radicals and deactivating excited oxygen molecules, a by-product of many metabolic processes.

DEFENSE MECHANISMS AGAINST FREE RADICAL OXIDATION Compartmentalization of oxidative metabolism Transition metal binding by transport and storage proteins Intracellular enzymes  Superoxide dismutase  Glutathione peroxidase  Catalase Dietary antioxidants  Vitamin E  Vitamin C  Carotenoids DNA repair mechanisms

STUDY OF PROBUCOL AND LOVASTATIN IN HYPERLIPIDEMIC RABBITS Extent of aortic lesions, % surface area involved Exp. groupTotal aortaAortic arch Untreated (n = 6) 40.6   3.5 Lovastatin (n = 11) 27.5   4.9 Probucol (n = 11) 14.3   5.3 Source: Carew T, et al. Proc Natl Acad Sci 1987; 84:

ANIMAL STUDIES OF VITAMIN E AND PREVENTION OF ATHEROSCLEROSIS SpeciesDoseEndpoint Restricted1,000 mg/kg feedDecreased plasma an ovulatory hensperoxides and aortic intimal thickening Hypercholesterolemic10 mg/kg bodyDecreased aortic mongrel rabbitsweightthickening Monkeys fed108 IU at entry orDecreased carotid atherogenic diet12 months afterultrasound stenosis atherogenic diet

PROSPECTIVE COHORT STUDIES OF ANTIOXIDANT VITAMINS AND CARDIOVASCULAR DISEASE Nurses’ Health Study Massachusetts Elderly Cohort Health Professionals Follow-up Study First National Health and Nutrition Examination Survey (NHANES I) Iowa Women’s Health Study

LIMITATIONS OF OBSERVATIONAL EVIDENCE Observational epidemiologic studies are unable to control for the potential effects of confounding variables not collected or not known to the investigators. When searching for small to moderate effects, the amount of uncontrolled confounding may be as large as the most likely effect.

NURSES' HEALTH STUDY: Antioxidant Vitamin Intake and Risk of CHD * Highest vs. lowest intake quintile AgentRelative Risk*P trend Beta-carotene Vitamin E0.66<0.001 Vitamin C Source: Manson JE, et al. J Am Coll Nutr 1993; 12:

Source: Rimm E, et al. NEJM 1993; 328. HEALTH PROFESSIONALS FOLLOW-UP STUDY: Antioxidant Vitamins and Risk of CVD * Highest vs. lowest quintile AgentRelative risk* P trend Beta carotene Vitamin E Vitamin C

ANTIOXIDANT VITAMINS AND CANCER PREVENTION Over 100 dietary and blood-based observational studies have suggested an inverse association between antioxidant vitamin intake or blood levels and risk of cancer.

The great tragedy of science: Beautiful hypotheses slain by ugly facts. Thomas Henry Huxley Collected Essays,

META-ANALYSIS OF EFFECT OF VITAMIN E ON MI, STROKE, OR CVD DEATH Source: N Engl J Med 2000; 342: StudyDaily DoseDuration (yr) RR (95% CI) ATBC ( ) CHAOS > ( ) GISSI ( ) HOPE ( ) Total0.97 ( )

CHINESE CANCER PREVENTION TRIAL Design: Double-blind, placebo-controlled trial of several vitamins and minerals Subjects: 29,584 residents aged 40 to 69 in 1985 living in Linxian, a rural county in north- central China Duration: 5 years

Relative risk of death by cause for those receiving ß-carotene, vitamin E, and selenium vs. those not receiving this cocktail CHINESE CANCER PREVENTION TRIAL Source: Blot WJ, et al. JNCI 1993; 85: Cause of Death N RR (95% CI) All causes2, ( ) All cancer ( ) Esophageal ( ) Gastric ( ) Cerebrovascular ( ) Other ( )

ALPHA-TOCOPHEROL BETA-CAROTENE STUDY Randomized, double-blind, placebo-controlled trial among 29,333 male smokers, aged 50 to 69, living in southwestern Finland Using a 2x2 factorial design, subjects were randomly assigned for ~ 6 years of treatment and follow-up to one of four treatment groups:  alpha-tocopherol (50 mg/daily)  beta-carotene (20 mg/daily)  both active agents  both placebos

ATBC STUDY: SUMMARY Alpha-Tocopherol (Vitamin E) No benefit on lung cancer, ischemic heart disease mortality, or total mortality Hemorrhagic stroke deaths  50% Prostate cancer incidence  34% Beta Carotene No benefit on lung cancer, ischemic heart disease mortality, or total mortality Lung cancer incidence  18% Ischemic heart disease mortality  11% Total mortality  8% Source: NEJM 1994; 330:

BETA-CAROTENE AND RETINOL EFFICACY TRIAL (CARET) Lung cancer  28%p = 0.02 CVD mortality  16%p = 0.06 Total mortality  17%p = 0.02 (N=18,314 current or former smokers and asbestos-exposed workers randomized to ß-carotene plus vitamin A vs. placebo) Source: Omenn GS, et al. NEJM 1996; 334:

PHYSICIANS’ HEALTH STUDY Beta-Carotene Findings Total malignant neoplasms  2% p = 0.65 ( ) Cardiovascular disease  p = 0.90 (MI, stroke, CV death)( ) Total mortality  2% p = 0.68 ( ) (N=22,071 U.S. male physicians, yrs, ß-carotene 50 mg QOD vs. placebo, duration = 12 yrs) Source: NEJM 1996; 334:

Design: Randomized, double-blind, placebo- controlled trial of daily vitamin E (400 or 800 IU) or placebo Subjects: 2,002 men and women in the UK with angiographically proven coronary atherosclerosis. Duration: median treatment and follow-up of 1.4 years CAMBRIDGE HEART ANTIOXIDANT STUDY (CHAOS)

(N=2,002 U.K. M & F with atherosclerosis, vit E [400 or 800 IU] or placebo, duration = 1.4 yrs) EndpointRelative risk (95% CI)P value Nonfatal MI + CVD death 0.53 ( ) Nonfatal MI0.23 ( )<0.001 CVD death1.18 ( ) 0.61 Source: Stephens NG, et al. Lancet 1996; 347:781-6.

Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardio (GISSI Prevention Study) Design: multicenter, open-label, 2x2 factorial trial of vitamin E (300 mg daily), fish oil supplement (n-3 PUFA,1 g daily), both, or neither Subjects: 1,665 women and 9,659 men with prior myocardial infarction Duration: mean, 3.5 years

Source: Lancet 1999; 354: Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardio (GISSI Prevention Study) (N=9,659 M + 1,665 F with prior MI, vitamin E [300 mg/d] with or w/o fish oil, duration = 3.5 yrs) Results for Vitamin E EndpointRelative risk (95% CI) MI + stroke + death0.95 ( ) MI + stroke + CV death0.98 ( ) All fatal events0.92 ( ) CV deaths0.94 ( )

HEART OUTCOMES PREVENTION EVALUATION (HOPE) STUDY Design: multicenter, double-blind, placebo-controlled, 2x2 factorial trial of vitamin E (400 IU daily), ramipril, both, or neither Subjects: 9,541 men and women at high risk of cardiovascular disease from 19 countries Duration: mean, 4.5 years

Source: N Engl J Med 2000; 342: HEART OUTCOMES PREVENTION EVALUATION (HOPE) STUDY (N=9,541 M & F from 19 countries, high risk of CVD, vitamin E [400 IU/d] with or w/o Ramipril, duration = 4.5 yrs) Results for Vitamin E EndpointRelative risk (95% CI) MI, stroke, or CV death1.05 ( ) CV death1.05 ( ) MI1.02 ( ) Death, any cause1.00 ( )

HEART PROTECTION STUDY (HPS) Preliminary results Simvastatin (40 mg/d)  12% total mortality  17% vascular mortality  24% CHD events  27% strokes AntioxidantsNo benefit or harm observed vitamin E (650 mg/d) vitamin C (250 mg/d) ß-carotene (20 mg/d) Source: Collins R, et al. International Journal of Clinical Practice 2002; 56:53-56.

PHYSICIANS' HEALTH STUDY Design: Randomized, double-blind, placebo- controlled, 2x2 factorial to low-dose aspirin (325 mg on alternate days) and beta-carotene (50 mg on alternate days) in the primary prevention of CVD and cancer Subjects: 22,071 healthy male physicians, aged 40 to 84 at baseline in 1982, living in the US Duration: 12 years

PRIMARY PREVENTION PROJECT (PPP) N=4,495 (M & F); 64.4 yrs (mean); 1+ CAD risk factor; F/U = 3.6 yrs Randomized controlled 2x2 factorial trial of vitamin E (300 mg/d) and low-dose aspirin (100 mg/d) Source: Collaborative Group of the Primary Prevention Project. Lancet 2001; 357:89-95 Vitamin E RR95% CI CV death + nonfatal MI + stroke1.07( ) All cardiovascular disease0.94( )

FIRST NATIONAL HEALTH AND NUTRITION EXAMINATION SURVEY (NHANES I) Vitamin C Intake and Risk of CVD Death (N=11,348) Daily Intake SMR* (95% CI) mg1.03( )  50 mg; no regular supplement use0.90( )  50 mg and regular supplement use0.66( ) *Compared with rates among U.S. whites

HDL-ATHEROSCLEROSIS TREATMENT STUDY (HATS) (160 participants [89% men], with clinical CAD, low HDL-C, and normal LDL-C, F/U = 3 yrs) Mean change inNonfatal MI, or Treatment Group% stenosisP-valuerevascularization,%P-value Simvastatin and niacin*-0.4< Antioxidants † ns ‡ Simvastatin and niacin, ns plus antioxidants Placebo ns * Doses were dependent on lipid levels † Vit E (800 IU) + vit C (1000 mg) + ß-carotene (25 mg) + selenium (100 µg) ‡ ns = nonsignificant Source: Brown BG, et al. NEJM 2001; 345:

SECONDARY PREVENTION WITH ANTIOXIDANTS OF CARDIOVASCULAR DISEASE IN ENDSTAGE RENAL DISEASE (SPACE) N=196 (69% men); yrs, hemodialysis patients with CVD, F/U = 1.4 yrs Treatment: Vitamin E (800 IU/d) or placebo OutcomeRR95% CI CVD Excluding sudden death0.46( ) Including sudden death0.54( ) Source: Boaz M, et al. Lancet 2000; 356:

AGE-RELATED EYE DISEASE STUDY (AREDS) N=3,640 (M & F), yrs, with mild to moderate age-related macular degeneration (AMD), F/U = 6.3 yrs Outcome: Progression to advanced AMD Source: Age-related Eye Disease Study Research Group. Arch Opthalmol 2001; 119: All Patients (mild/moderate AMD) Treatment GroupOR99% CI Antioxidants only* 0.80( ) Zinc only0.75( ) Antioxidants plus zinc0.72( ) Placebo1.00(Referent) * Vit C (500 mg) + vit E (400 IU) + ß-carotene (15 mg)

ONGOING LARGE-SCALE TRIALS OF ANTIOXIDANTS Physician's Health Study IIVitamin E (400 IU QOD), vitamin C (PHS II)(500 mg/d), and a daily multivitamins in U.S. male physicians Women's Health StudyVitamin E (400 IU QOD) and low-dose (WHS)aspirin in healthy U.S. female health professionals Women's Antioxidantß-carotene (50 mg QOD), vitamin E Cardiovascular Study(600 IU QOD), vitamin C (500 mg/d), (WACS)and folic acid/B 6 and B 12 in high-risk U.S. female health professionals

CONCLUSIONS Antioxidant vitamin supplements represent a promising, but unproven, means of reducing risk of CVD, cancer, and other chronic diseases It would be premature to recommend routine use of antioxidants for disease prevention or treatment Dietary intake of 5-7 servings/d of fruits and vegetables, and a daily multivitamin supplement, would be prudent Additional large-scale randomized clinical trials of antioxidants, alone and in combination, are needed.

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