Researchers at Oxford Population Health studying genetic variants that control levels of Lipoprotein(a), or Lp(a) discovered that lowering Lp(a) could reduce the risk of heart attack and large artery stroke in both East Asians and Europeans. The study is published in Circulation.
Lp(a) is a type of lipoprotein particle that is produced in the liver and carried in the blood. It is similar to a low-density lipoprotein (LDL) particle (that carries LDL-cholesterol), but in addition has an apolipoprotein(a) on its surface. Blood levels of Lp(a) in individuals are largely genetically determined.
Previous studies reported that higher blood levels of Lp(a) were strongly associated with higher risks of heart attack and only weakly with stroke in Europeans. It has been unclear whether higher levels of Lp(a) affect heart attack and stroke in East Asians that have a different genetic architecture to Europeans.
In this study, researchers examined the genetic determinants of Lp(a) in blood samples from 18,174 East Asians in the China Kadoorie Biobank to discover genetic variants that affect Lp(a) levels and compared their results with Europeans. Analyses of genetic variants affecting Lp(a) in population studies of heart attack and stroke cases in both populations enabled scientists to predict whether both could benefit from having lower levels of Lp(a).
Key findings:
- The 29 genetic variants identified that control blood levels of Lp(a) in East Asians differ from those in Europeans, but higher blood levels of Lp(a) had comparable relative risks of heart attack for equivalent differences in Lp(a) levels in East Asians and in Europeans;
- The risks for equivalent differences in blood levels of Lp(a) were 3-fold greater for heart attack than for ischemic stroke and were largely limited to stroke types due to a
blockage in blood supply to the brain and unrelated to stroke due a bleed in the brain.
Robert Clarke, Emeritus Professor of Epidemiology and Public Health Medicine at Oxford Population Health, said ‘Our results in East Asians are consistent with previous population studies that discovered that Lp(a) is an important target for drug treatment to prevent heart attack in Europeans and suggest that both European and East Asian populations could benefit equally from novel treatments to lower Lp(a), despite there being a lower proportion of elevated Lp(a) levels in East Asian populations.’
Sarah Parish, Emeritus Professor of Medical Statistics and Epidemiology said ‘Our results demonstrated that the effects of Lp(a) on risk of heart attack were three-fold greater than on stroke but this is largely limited to large artery stroke types. This suggests that while new treatments targeting Lp(a) levels may be beneficial in preventing heart attack, in terms of stroke prevention the effects are likely to be limited to large artery types.’
The China Kadoorie Biobank is a collaborative study between Oxford Population Health and Peking University which recruited 500,000 adults from 10 diverse areas in China from 2004─2008.