Non-high density lipoprotein cholesterol is the best discriminator of myocardial infarction in young individuals.

BACKGROUND

Several studies have shown that non-high density lipoprotein (HDL) cholesterol is a strong and independent predictor of cardiovascular events. We investigated whether non-HDL cholesterol can discriminate young individuals with myocardial infarction (MI) from age- and sex-matched controls.

METHODS

We conducted a case-control study which included 100 consecutive patients who had survived their first MI before the age of 36 years and 100 age- and sex-matched healthy controls without a history of cardiovascular disease. Cardiovascular risk factors were reported and fasting lipids and apolipoproteins were measured.

RESULTS

Patients with premature MI had significantly higher levels of total cholesterol, low density lipoprotein cholesterol, triglycerides, apolipoprotein B, lipoprotein (a) and non-HDL cholesterol and significantly lower levels of HDL cholesterol and apolipoprotein A. Multivariate logistic regression analysis showed that for every 10mg/dl increase in non-HDL cholesterol levels, the odds of having a MI were increased by 34% after controlling for age, sex, body mass index, presence of hypertension, diabetes and smoking habits. Moreover, participants in the highest tertile of non-HDL cholesterol levels had 28-fold higher odds for having a MI (95% confidence interval, 7.5-104.1), compared to those in the lowest tertile. Finally, discriminant analysis showed that non-HDL cholesterol (lambda-Wilks=0.68) was the strongest discriminator for MI among all studied risk factors while smoking (lambda-Wilks=0.80) was the strongest discriminator for MI among the non-lipid risk factors.

CONCLUSIONS

Our study suggests that among conventional lipid and non-lipid risk factors non-HDL cholesterol is the best discriminator to predict the presence of MI in individuals under the age of 36 years.