thromboxane A2 that promotes a cascade of events leading ultimately to clot formation.
Increased homocysteine levels affect the inner lining of the arterial wall, and thus have
long been implicated in the causation of thrombosis (Scott, J. and Weir, D., 1996). In
fact, increased homocysetine levels associated with syndrome of homocysteinuria are
acknowledged to be a cause of intravascular thrombosis. It has been observed that plasma
homocysteine is normally converted to methionine co-factored by folic acid correlates in
the body. When this reaction is impaired due to deficiency of cobalamine; since
cobalamine regulates folate metabolism, it is deranged leading to elevated homocysteine
levels (Mayer, E.L., Jacobsen, D.W., and Robinson, K., 1996). High plasma
homocysteine, thus, will predispose to increased thrombosis, although it is not yet known
whether hyperhomocysteinaemia due to folic acid deficiency predisposes to thrombosis
or alters its response to treatment (Welch, G.N. and Loscalzo, J., 1998). This proposal
aims to study the effect of folic acid on the elderly in terms of risk of coronary artery
disease as relevant to prevention of thrombosis in preexisting atherosclerotic heart
disease in terms of incidence of myocardial infarction (Bots, M.L. et al., 1999).
Increasingly, healthcare is focusing towards prevention of disease rather than
treating it after the catastrophe happens. Coronary artery disease manifested by acute
myocardial infraction is one of the most common diagnoses in developed countries
throughout the world. The mortality rate of the disease is 30% with over half the patients
expiring even before they are able to reach the hospital. Survival from a heart...
Research nurses will screen the medical records and exclude patients who have a history of coronary heart diseases or patients who are taking drugs known to interfere with folic acid, or taking vitamin supplements containing folic acid. Patients will be eligible for inclusion if aged 65 years or more and if their medical histories include two or more of the following conditions: diabetes, hypertension, hyperlipidemia, obesity or smoking. All eligible individuals will receive a letter from the hospital explaining the study, followed by a telephone call inviting them to attend the first visit and instructing them to fast from midnight the night before the visit. At the first visit, all baseline measurements will be taken. Research nurses will take general information, such as, name, age, sex, phone number, address, smoking history, marital status, socioeconomic factors, and the names and phone numbers of two or three friends or relatives who always know how to reach the participants. Drugs history including aspirin or other anticoagulants, antihypertensive, anti-angina, and lipid-lowering drugs will be reviewed. Study procedures will be explained to all subjects. Subjects who are unlikely to complete follow-up due to plans to move or due to disease likely to be fatal within 4 years, or unwilling to participate will be excluded from the study.
Ethics: All subjects will be explained the study protocol, and a written informed consent will