Folate and risk of cardiovascular disease
BMJ 2003; 326 doi: https://doi.org/10.1136/bmj.326.7397.1035/a (Published 10 May 2003) Cite this as: BMJ 2003;326:1035
Study results were misinterpreted
- David S Wald, specialist registrar in cardiology (davidwald@hotmail.com),
- Malcolm Law, professor,
- Joan Morris, senior lecturer,
- Nicholas J Wald, professor
- Southampton General Hospital, Southampton SO16 6YD
- Department of Environmental and Preventive Medicine, London EC1M 6BQ
- School of Medicine and Pharmacology, University of Western Australia, Nedlands, WA 6009, Australia
EDITOR—Hung et al conclude that their cohort study on serum folate and coronary heart disease provides evidence against the view that folic acid prevents coronary heart disease.1 We disagree and believe they have misinterpreted their results.
A meta-analysis of studies on homocysteine and cardiovascular disease, supported by others,2–4 together with randomised trial evidence on folic acid dose and serum homocysteine reduction, shows that the maximal homocysteine lowering effect of folic acid occurs at a dose of about 0.8 mg/day (which increases serum folate by 20 µg/l).5 This homocysteine reduction lowers the risk of coronary heart disease by about 16%. The difference in average serum folate between the highest and the lowest folate group in the cohort study of Hung et al was about 7 µg/l, since the …