Vitamin C intake and risk of ischemic heart disease in a population with a high prevalence of smoking

OBJECTIVE: Epidemiological data on the relationship between vitamin C intake and ischemic heart disease (IHD) risk are limited in the Asian population, with a high prevalence of smoking. This study aims to investigate the association between vitamin C intake and the incidence of non-fatal IHD in Korean men. METHODS: The case group consisted of 108 patients with electrocardiogram-confirmed myocardial infarction or angiographically confirmed (>or=50% stenosis) coronary artery disease (CAD) who were admitted to a university teaching hospital in Seoul, Korea. The controls were 142 age-matched patients admitted to the departments of ophthalmology and orthopedic surgery at the same hospital. Vitamin C intake was assessed by a nutritionist using a semi-quantitative food frequency method, and body mass index (BMI), tobacco use and past history of cardiovascular disease were determined by examination and interview. RESULTS: After controlling for cardiovascular risk factors, including BMI, smoking, past history of hypertension, past history of hyperlipidemia, dietary intakes of energy, total fat (or subtype of fat), cholesterol, beta-carotene, and vitamin E, the odds ratio (OR) of non-fatal IHD was 0.34 (95% confidence interval (CI) 0.13-0.90) in the highest tertile of vitamin C intake compared with those in the lowest tertile. In a subgroup analysis, which compared nonsmokers in the highest tertile of vitamin C intake to current smokers in the lowest tertile of vitamin C intake, the odds ratio of developing non-fatal IHD was 0.12 (95% CI 0.02-0.77). CONCLUSION: This study suggests that higher intake of vitamin C is associated with the decreased risk of non-fatal IHD in a population with a high prevalence of smoking.