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Homocysteine and ischaemic heart disease in the Caerphilly cohort
J B Ubbink1, A M Fehily, J Pickering
1University of Pretoria, Department of Chemical Pathology, Faculty of Medicine, South Africa. jubbink@medic.up.ac.za
Insights
Elevated homocysteine levels show a weak association with ischaemic heart disease (IHD) risk. After adjusting for other factors, this link became statistically insignificant in the Caerphilly cohort study.
Area of Science:
- Cardiovascular Epidemiology
- Clinical Biochemistry
- Nutritional Science
Background:
- Elevated circulating total homocysteine (tHcy) is linked to increased ischaemic heart disease (IHD) prevalence.
- Understanding the predictive value of tHcy for IHD is crucial for cardiovascular risk assessment.
Purpose of the Study:
- To evaluate the predictive power of serum total homocysteine concentration for future IHD events.
- To assess the association between tHcy levels and incident IHD in a population-based cohort.
Main Methods:
- Prospective cohort study (Caerphilly Prospective Cohort Study) involving 2290 men aged 50-64 years.
- Measurement of serum total homocysteine concentrations and follow-up for 5 years to identify IHD events (fatal and non-fatal myocardial infarction, ECG-defined MI).
- Logistic regression analysis was used to assess the association, adjusting for confounding factors like age, smoking, BMI, diabetes, and HDL-cholesterol.
Main Results:
- The mean tHcy level was slightly higher in men who experienced an IHD event (12.4 micromol/l) compared to those who did not (11.7 micromol/l).
- After adjusting for confounding factors, the difference in tHcy levels was not statistically significant (P > 0.05).
- Vitamin status and alcohol intake were significant negative determinants of tHcy; alcohol's effect was attributed to folic acid in beer.
Conclusions:
- Serum total homocysteine concentration appears to be a weak predictor of IHD events in this cohort.
- Adjustments for confounding factors attenuated the relationship between tHcy and IHD, rendering it statistically non-significant.
- Folic acid intake, particularly from beer, influences tHcy levels.
Abstract:
Elevated circulating total homocyst(e)ine concentrations are associated with a higher prevalence of ischaemic heart disease (IHD). We utilized data from the Caerphilly Prospective Cohort Study to assess the predictive power of the serum total homocyst(e)ine concentration for future IHD. Serum total homocyst(e)ine concentrations were measured in 2290 men in the Caerphilly cohort, a representative population sample of men aged 50-64 years. During a 5-year follow-up period, 56 men suffered fatal IHD, 77 had a non-fatal myocardial infarction, while 21 were found to have ECG evidence of myocardial infarction (MI) when examined at follow-up. The mean serum total homocyst(e)ine concentration in the total of 154 men who experienced an incident IHD event was 12.4 micromol/l, whereas the 2136 men who experienced no such event had a mean level of 11.7 micromol/l. The difference between these means, examined by logistic regression and standardising for the effects of differences in age, social class, smoking, BMI, diabetes, HDL-cholesterol and prevalent IHD is 0.47 micromol/l (95% CI = -0.13 to 1.11 micromol/l). The mean difference for the 56 men who died, and whose death was attributed to IHD, is 0.81 micromol/l (95% CI= -0.17 to 1.88 micromol/l) after correction for confounding factors. Vitamin nutritional status and alcohol intake were significant negative determinants of serum total homocyst(e)ine concentrations; the effect of alcohol is explained by the folic acid content of beer, which is the preferred alcoholic beverage in Caerphilly. It is concluded that the serum total homocyst(e)ine concentration is weakly predictive of IHD events, though in the present data adjustments for other factors attenuated the relationship and it became not statistically significant (P > 0.05).