Lipoprotein (a) as a predictor of myocardial infarction in middle-aged men.
OBJECTIVE
Whether serum lipoprotein (a) [Lp(a)] levels are an independent risk factor for coronary heart disease has been controversial. We have investigated its status in a prospective population survey, the Second Northwick Park Heart Study.


METHODS
We recruited 2,616 men 50 to 61 years old from nine primary care practices in the United Kingdom. Baseline serum Lp(a) levels were measured by enzyme-linked immunosorbent assay (ELISA) and were analyzed in 3 groups (<25th percentile, 25th to 75th percentile, and >75th percentile) to overcome the problem of some measurements falling below the threshold of the assay. Coronary end points included sudden cardiac death, acute myocardial infarction, silent myocardial infarction on the electrocardiogram, and coronary artery bypass surgery.


RESULTS
During a mean of 6 years of follow-up, 121 men had coronary events. In a multivariate analysis that also adjusted for fibrinogen, Apo-A1, Apo-B, and triglyceride levels, we identified several independent risk factors for coronary events, including cholesterol level (hazard ratio [HR] = 1.5 per SD 95% confidence interval [CI] 1.3 to 1.8), diabetes (HR = 4.1, 95% CI: 2. 0 to 8.4), current versus never smoking (HR = 2.5, 95% CI: 1.5 to 4.1), diastolic blood pressure (HR = 1.4 per SD, 95% CI: 1.1 to 1.7), Apo-A1 (HR = 0.8 per SD, 95% CI: 0.6 to 0.9), age (HR = 1.3 per SD, 95% CI: 1.1 to 1.6), and Lp(a) (>26.3 mg/dL [75th percentile] versus <2.9 mg/dL [25th percentile], HR = 1.9, 95% CI: 1.1 to 3.3]. There was a statistically significant (P = 0.01) difference in risk between the three levels of Lp(a).


CONCLUSIONS
We found that a high Lp(a) level was an independent predictor of the development of coronary heart disease in middle-aged men.
Seed
M
M
Department of Vascular Medicine (MS), Charing Cross Hospital, National Heart and Lung Institute Division of Imperial College School of Medicine, England, London, United Kingdom.
Ayres
K L
KL
Humphries
S E
SE
Miller
G J
GJ
D016632:Apolipoprotein A-I / Q000097:blood; D001055:Apolipoproteins B / Q000097:blood; D001026:Coronary Artery Bypass; D016757:Death, Sudden, Cardiac; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000097:blood* / Q000401:mortality; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D006113:United Kingdom
D016632:Apolipoprotein A-I; D001055:Apolipoproteins B; D017270:Lipoprotein(a)