Elevated lipoprotein(a) ups risk of ischaemic stroke
The risk of ischaemic stroke appears to increase with high plasma levels of lipoprotein(a) both observationally and causally from human genetics, according to a recent study.
Multivariable analysis revealed that lipoprotein(a) levels >93 mg/dl (>199 nmol/L: 96th to 100th percentile), compared with levels <10 mg/dl (<18 nmol/l: first to 50th percentile), correlated with a higher risk of ischaemic stroke (adjusted hazard ratio [HR], 1.60, 95 percent CI, 1.24–2.05).
Observational analyses for a 50-mg/dl (105 nmol/l) higher lipoprotein(a) level showed a 1.20 (1.13–1.28) age- and sex-adjusted HR for ischaemic stroke; the corresponding age- and sex-adjusted genetic causal risk ratios for LPA kringle-IV type 2 (KIV-2) number of repeats and for LPA rs10455872 were 1.20 (1.02–1.43) and 1.27 (1.06–1.51).
Active smokers aged >70 years with hypertension and lipoprotein(a) levels >93 mg/dl (>199 nmol/l: 96th to 100th percentile) had the highest absolute 10-year risk of ischaemic stroke at 17 percent.
In the Copenhagen City Heart Study, high lipoprotein(a) levels showed identical trends in risk estimates but did not reach statistical significance.
This large, contemporary, general population study aimed at determining whether high lipoprotein(a) was associated with high risk of ischaemic stroke. It analysed 49,699 individuals from the Copenhagen General Population Study and 10,813 individuals from the Copenhagen City Heart Study with measurements of plasma lipoprotein(a), KIV-2 number of repeats and LPA rs10455872.
The investigators established the endpoint of ischaemic stroke from Danish national health registries, which was then validated by medical doctors.
“High lipoprotein(a) is associated with increased risk of myocardial infarction and aortic valve stenosis,” the investigators said. “Previous studies have examined the association of lipoprotein(a) and risk of stroke, [but] the results are conflicting.”