Grant: Operating Grant

Heart disease is a leading cause of death in Canada. In addition to risk factors such as smoking and diabetes, increased fats and cholesterol in the blood can lead to narrowing and blockage of the blood vessels to the heart. These fats and cholesterol are carried in the blood in packages called lipoproteins. Increased amounts of one of these packages in the blood, called lipoprotein(a)[ Lp(a) ], is associated with increased risk of heart and blood vessel disease. However, the real importance of Lp(a) is not yet clear because people of differing genetic ancestry have varying amount and sizes of Lp(a). The size of Lp(a) is determined by our genes. The different sizes of Lp(a) make it difficult to measure in the blood. Another challenge is that smaller size Lp(a) packages lead to larger number of the Lp(a) packages in the blood. People can have their Lp(a) measured using different types of tests. The tests can either measure how much of the lipoprotein is in the blood, determine the Lp(a) gene type or look at the size of Lp(a). At the moment, we are not sure if there is one best test to use in all ethnic groups or if it is better to use a combination of tests. We plan to use 4 different laboratory techniques. One will measure the amount of Lp(a). The second will identify the genetic factors. The other two will determine the different sizes of Lp(a) in each blood sample. We will use blood samples from a very large international study (the INTERHEART study) which was designed to allow us to understand the factors that can be used to predict the risk of someone having a heart attack. The INTERHEART study involved more than 20,000 women and men, young and old, from 52 countries and many ethnic groups. The study we propose is the first to combine these 4 laboratory techniques in a large number of people from many ethnic groups to try to fully understand Lp(a) and its value in helping to predict the risk of developing heart and blood vessel disease.