High Lipoprotein(a) Levels Linked to Heart Attack
High lipoprotein(a) levels associated with fewer repeats in the KIV-2 gene
TUESDAY, June 9 (HealthDay News) -- Patients who have elevated levels of lipoprotein(a) for genetic reasons are at higher risk of having a heart attack, according to a study in the June 10 issue of the Journal of the American Medical Association.
Pia R. Kamstrup, M.D., from Copenhagen University Hospital in Herlev, Denmark, and colleagues examined the association between plasma lipoprotein(a) levels, kringle IV type 2 (KIV-2) size polymorphisms, which correlate inversely with levels of lipoprotein(a), and myocardial infarction in three groups totaling 40,486 patients with 2,824 myocardial infarctions.
The researchers found that after adjusting for confounding factors, the risk of myocardial infarction increased with increasing lipoprotein(a) levels (maximum hazard ratio, 2.6). Patients with a greater number of KIV-2 repeats had lower levels of lipoprotein(a), and the number of KIV-2 repeats could explain 21 to 27 percent of the variability in lipoprotein(a) levels. After adjusting for other factors, the authors note that the risk of myocardial infarction was higher for patients with fewer KIV-2 repeats. The instrumental variable estimate of the hazard ratio for myocardial infarction was 1.22 for a doubling of genetically elevated lipoprotein(a) levels.
"The present study demonstrated an association between lipoprotein(a) level and myocardial infarction, an association between KIV-2 genotype and lipoprotein(a) level, and an association between KIV-2 genotype and myocardial infarction," Kamstrup and colleagues conclude. "These data are consistent with a causal association between elevated lipoprotein(a) levels and increased risk of myocardial infarction."
Authors of the study reported financial relationships with the pharmaceutical industry.