If you're worried about reducing your risk of heart disease, you probably already know that you should quit smoking, follow a healthy diet, exercise regularly, keep your blood pressure in check, and make sure your cholesterol levels aren't too high. But, do you know what your lipoprotein (a) levels are?
Well, if you don't have a family history of early heart disease or have unexplained heart disease yourself, you probably don't need to know how much lipoprotein (a) is lurking in your blood.
But, if any males in your family had a heart attack before age 55, or any of the women had heart disease before 65, you should have your lipoprotein levels checked. Ditto if you have heart disease, and you don't have any of the usual risk factors, such as obesity and high blood pressure.
"Lipoprotein (a) tests give us interesting information, but it's still not a first line test for heart disease risk," explained Dr Nieca Goldberg, director of the NYU Langone Medical Centre's Women's Heart Program in New York City.
What are lipoproteins?
Lipoprotein (a) is a molecule that circulates in the blood that's very similar to LDL - the bad - cholesterol, and is also similar to a blood-clotting protein. "It's the worst of both worlds," said Goldberg.
Lipoproteins carry fat through the blood. Sometimes those fats are used for important functions, such as producing cell membranes. But, if you have too much lipoproteins in your blood, those fats can start collecting on your artery walls, eventually choking them off.
Lipoprotein (a) became more well known after a 2006 study, published in the Journal of the American Medical Association, found that women who had the highest levels of lipoprotein (a) - above 65 milligrams per decilitre of blood - had a 67% higher risk of heart disease or stroke compared to women with low lipoprotein (a) levels.
Normal values of lipoprotein (a) are below 30 milligrams per decilitre of blood, according to the US National Institutes of Health.
High levels of lipoprotein up heart risk
The study, which included data from 28 000 women, also found that when women had a lipoprotein level above 65 milligrams per decilitre of blood and an LDL reading above 120 milligrams per decilitre, the risk of heart disease was increased by 80%.
"People who have high levels of lipoprotein (a) are more likely to develop heart disease. It's a risk factor," said Dr Souheil Saba, a cardiologist at Providence Hospital in Southfield, Mich. But, he said, it's not a test that's routinely used.
"The main reason we check lipoprotein (a) is for people who have unexplained heart disease and a lack of traditional risk factors," Saba said. Also, if you know someone else in your family has high levels of lipoprotein (a), it's a good idea to get tested to see if your levels are elevated, he added.
Goldberg agreed - it's not a test for everyone, but for many, it can be extremely valuable.
"It [lipoprotein (a)] is a risk marker for heart disease, but you don't need to jump up and get it tested. Just get the baseline check-up. That's where we pick up obvious risk factors that cause heart disease, like a lack of exercise, smoking, high blood pressure and high cholesterol," she said.
If levels of lipoprotein (a) are elevated, Saba said, there are treatments available. – (HealthDay News, October 2008)
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