Dietary antioxidants and the prevention of CHD evidence from clinical trials

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While most epidemiological studies have demonstrated that dietary intake of vitamin E is inversely related to coronary heart complications, supplementation studies gave conflicting results. Clinical trials with antioxidants have been done in patients with or without previous history of cardiovascular disease (Table 5.2). Surrogate endpoints, such as analysis of atherosclerosis progression, or 'hard' endpoints, such as vascular death and MI, have been used to evaluate the clinical benefits of antioxidant vitamins. The Alpha-Tocopherol-Beta-Carotene-Cancer (ATBC)52 prevention study was a randomized, double-blind, placebo-controlled primary-prevention trial to determine whether daily supplementation with alpha-tocopherol, beta-carotene or both reduced the incidence of lung cancer and other cancers. A total of 29 133 male smokers, 50-69 years of age, were randomly assigned to one of four regimens: alpha-tocopherol (50 mg per day) alone, beta-carotene (20 mg per day) alone, both alpha-tocopherol and beta-carotene, or placebo for 5-8 years of follow up. The results of this trial showed no beneficial effect of supplemental vitamin E (alpha-tocopherol) or beta-carotene in terms of the prevention of lung cancer, but the authors observed a reduction for death due to cardiovascular events in the group treated with alpha-tocopherol. For this reason, the authors made a sub-analysis analysing the clinical efficacy of 50 mg/day vitamin E in a population suffering from coronary heart disease, and showed no change in cardiovascular events during the follow up.53

The Cambridge Heart Antioxidant Study (CHAOS) tested whether treatment with a high dose of alpha-tocopherol would reduce subsequent risk of MI and cardiovascular death in patients with established ischaemic heart disease. In this double-blind, placebo-controlled study with stratified randomization, 2002 people with angiographically proven coronary atherosclerosis were enrolled and followed up for a median of 510 days (range 3-981). Alpha-tocopherol was assigned to 1035 people (capsules containing 800 IU daily for first 546 patients;

Table 5.2 Summary of randomized trials of vitamin E treatment

Trial Patients' characteristics

Location of Number in study treatment group population Vitamin Control E

ATBC 1862 men, smokers, aged between 50 and 69 years, who had a previous MI CHAOS54 Median age 62 years;

angiographically proven CVD;

84% male (n = 2002) GISSI56 Survivors of recent MI

(<3 months); 85% male (n = 11324) HOPE58 Mean age 66 years;

known cardiovascular disease or diabetes; 73% male (n = 9541) SPACE59 Haemodialysis patients with pre-existing cardiovascular disease (n = 196) aged 40-75 years

Finland

UK, single centre

Italy, multicentre

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A Disquistion On The Evils Of Using Tobacco

A Disquistion On The Evils Of Using Tobacco

Among the evils which a vitiated appetite has fastened upon mankind, those that arise from the use of Tobacco hold a prominent place, and call loudly for reform. We pity the poor Chinese, who stupifies body and mind with opium, and the wretched Hindoo, who is under a similar slavery to his favorite plant, the Betel but we present the humiliating spectacle of an enlightened and christian nation, wasting annually more than twenty-five millions of dollars, and destroying the health and the lives of thousands, by a practice not at all less degrading than that of the Chinese or Hindoo.

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