A prospective study of triglyceride level, low-density lipoprotein particle diameter, and risk of myocardial infarction.
OBJECTIVE
To test whether a predominance of small, dense low-density lipoprotein (LDL) particles and elevated triglyceride levels are independent risk factors for myocardial infarction (MI).


METHODS
Nested case-control study with prospectively collected samples.


METHODS
Prospective cohort study.


METHODS
Blood samples were collected at baseline (85% nonfasting samples) from 14916 men aged 40 to 84 years in the Physicians' Health Study.


METHODS
Myocardial infarction diagnosed during 7 years of follow-up.


RESULTS
Cases (n=266) had a significantly smaller LDL diameter (mean [SD], 25.6 [0.9] nm) than did controls (n=308) matched on age and smoking (mean [SD], 25.9 [8] nm; P<.001). Cases also had higher median triglyceride levels (1.90 vs 1.49 mmol/L [168 vs 132 mg/dL]; P<.001). The LDL diameter had a high inverse correlation with triglyceride level (r=-0.71), and a high direct correlation with high-density lipoprotein cholesterol (HDL-C) level (r=0.60). We observed a significant multiplicative interaction between triglyceride and total cholesterol (TC) levels (P=.01). After simultaneous adjustment for lipids and a variety of coronary risk factors, LDL particle diameter was no longer a statistically significant risk indicator, with a relative risk (RR) of 1.09 (95% confidence interval [CI], 0.85-1.40) per 0.8-nm decrease. However, triglyceride level remained significant with an RR of 1.40 (95% CI, 1.10-1.77) per 1.13 mmol/L (100-mg/dL) increase. The association between triglyceride level and MI risk appeared linear across the distribution; men in the highest quintile had a risk about 2.5 times that of those in the lowest quintile. The TC level, but not HDL-C level, also remained significant, with an RR of 1.80 (95% CI, 1.44-2.26) per 1.03-mmol/L (40-mg/dL) increase.


CONCLUSIONS
These findings indicate that nonfasting triglyceride levels appear to be a strong and independent predictor of future risk of MI, particularly when the total cholesterol level is also elevated. In contrast, LDL particle diameter is associated with risk of MI, but not after adjustment for triglyceride level. Increased triglyceride level, small LDL particle diameter, and decreased HDL-C levels appear to reflect underlying metabolic perturbations with adverse consequences for risk of MI; elevated triglyceride levels may help identify high-risk individuals.
Stampfer
M J
MJ
Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, Mass 02115, USA.
Krauss
R M
RM
Ma
J
J
Blanche
P J
PJ
Holl
L G
LG
Sacks
F M
FM
Hennekens
C H
CH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008055:Lipids / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood / Q000737:chemistry*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood*
D008055:Lipids; D008077:Lipoproteins, LDL; D014280:Triglycerides