Medical researchers at the University of Otago have shown a seldom-measured lipoprotein in the blood is a strong indicator of risk for four distinct forms of vascular disease.

Lipoprotein(a) - Lp(a) - has already been identified as a risk factor for coronary artery disease but, until this research project (published recently in the American journal Clinical Chemistry), no one had shown that it was also a risk factor for stroke, peripheral vascular disease (PVD) and abdominal aortic aneurysm (AAA) within the same population.

Vascular Research Group head Dr Greg Jones and Lipoprotein Research Group head Dr Sally McCormick collaborated on the project and say the study is significant because it is the first time that Lp(a) has been studied in this way within a single population sample.

Dr Jones says 1255 patients from the Otago region were examined in the study and all were already being heavily medicated for lowering other vascular risk factors, such as triglycerides and cholesterol.

"We actually wanted to see if Lp(a) stood out when the other lipid risk factors were being medicated for with the new generation of statins - and it did."

One of the problems is that Lp(a) is strongly genetically determined. This, plus the fact that it cannot be lowered much by drugs or diet, are the main reasons clinicians give for not testing for it.

However, Dr Jones says it should actually provide an incentive for clinicians to manage the other risk factors and help them make choices between lifestyle intervention and medication.

"If Lp(a) is low, you might recommend a lifestyle intervention, but if it is high, a more aggressive approach to controlling other risk factors may be more appropriate."

From a clinical perspective, he says it is valuable to have a risk factor marker that is relevant to a range of vascular disease.

Meanwhile, Dr McCormick's laboratory is shifting its focus to the underlying genetics behind Lp(a) levels and developing a means of lowering levels, perhaps by developing a drug that will specifically lower Lp(a).

"We are also looking at different sizes of Lp(a) proteins, to see if that can add another layer of risk management."

Dr McCormick says the collaboration between the two research groups has been a rewarding one. "It has allowed a valuable link from laboratory bench to the clinic and back again."