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Hyperhomocysteinaemia and premature coronary artery disease in the Chinese
Y I Lolin1, J E Sanderson, S K Cheng
1Department of Chemical Pathology, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong.
Insights
Hyperhomocysteinemia is not an independent risk factor for coronary artery disease in Hong Kong Chinese, though it is linked to smoking. Vitamin B-12 and folate levels did not appear to cause hyperhomocysteinemia in this study.
Area of Science:
- Cardiovascular Disease Research
- Metabolic and Nutritional Science
Background:
- Premature atherosclerotic coronary artery disease (CAD) poses a significant health challenge.
- Hyperhomocysteinemia, an elevation of homocysteine levels, is a potential risk factor for cardiovascular diseases.
- Understanding the prevalence and associations of hyperhomocysteinemia in specific populations, like Hong Kong Chinese, is crucial for targeted prevention strategies.
Purpose of the Study:
- To investigate the prevalence of hyperhomocysteinemia in Hong Kong Chinese patients with premature CAD.
- To compare hyperhomocysteinemia with traditional risk factors and vitamin status in this patient group.
- To determine if hyperhomocysteinemia is an independent risk factor for CAD in this population.
Main Methods:
- A case-control study was conducted involving 45 patients with premature CAD and 23 healthy controls, all under 55 years old.
- A standardized methionine-loading test was employed to assess homocysteine metabolism.
- Coronary artery disease, traditional risk factors, and vitamin status (folate, vitamin B-12) were evaluated.
Main Results:
- Patients with premature CAD showed a higher prevalence of fasting and post-methionine hyperhomocysteinemia compared to controls.
- Smoking was significantly more frequent among patients with hyperhomocysteinemia.
- Hyperhomocysteinemic patients exhibited higher fasting plasma cholesterol levels, while vitamin B-12 levels were not reduced and folate levels were higher.
Conclusions:
- Hyperhomocysteinemia is associated with smoking and elevated cholesterol in Hong Kong Chinese patients with premature CAD.
- While the prevalence is similar to white subjects, hyperhomocysteinemia does not appear to be an independent risk factor for CAD in this population.
- Folate and vitamin B-12 deficiencies were not identified as causes of hyperhomocysteinemia in this pilot study, suggesting multifactorial origins.
Objectives:
To examine the prevalence of hyperhomocysteinaemia and compare it with the classic risk factors and vitamin status in Hong Kong Chinese patients with premature atherosclerotic coronary artery disease.
Design:
Case-control study.
Setting:
General hospital and community.
Subjects:
Forty five patients (39 males) with significant coronary artery disease confirmed by angiography (32 post myocardial infarction) and 23 healthy volunteers (17 male), all aged less than 55 years.
Intervention:
Standardised methionine-loading test.
Main Outcome Measures:
Coronary artery disease, risk factors.
Results:
More patients than controls had fasting hyperhomocysteinaemia (10/45 v 2/23, P = 0.122), post-methionine hyperhomocysteinaemia (17/45 v 1/23, P = 0.008), and an abnormal response to methionine (15/45 v 1/23, P = 0.015). A history of smoking was more frequent in patients (3/23 v 25/45, P = 0.002). Sixteen of 17 patients with hyperhomocysteinaemia but only nine of 28 with normohomocysteinaemia were smokers (P = 0.0002). Fasting plasma cholesterol concentrations (mean (SD)) were higher in hyperhomocysteinaemic patients (6.41 (1.58) mmol/l) than in controls (5.53 (0.90) mmol/l) (P = 0.042). Serum vitamin B-12 was not reduced and serum folate was higher in hyperhomocysteinaemic patients (35 (4) nmol/l) than normohomocysteinaemic patients (26 (9) nmol/l) (P = 0.009).
Conclusions:
Although the prevalence of hyperhomocysteinaemia in Hong Kong Chinese is similar to that in white subjects, hyperhomocysteinaemia is not an independent risk factor for coronary artery disease and is associated with smoking. This may be of some consequence in view of the change to a more Western diet with more animal protein, and therefore methionine, coupled with a high frequency of cigarette smokers in this region. The causes of the hyperhomocysteinaemia are multifactorial but in this pilot study a deficiency of folate and/or vitamin B-12 did not seem to be one of them.