There are two types of cholesterol: high (HDL) and low density (LDL) or “bad” cholesterol. High levels of LDL put a person at much more risk of cardiovascular disease, a range of conditions including stroke, heart attack and atherosclerosis.

Cardiovascular disease is the leading cause of death globally, so scientists are very interested in ways to catch heart disease early — before it develops into a chronic condition or an acute event like a heart attack. Catching heart disease early means that interventions like statins and lifestyle changes can be implemented to lower and even reverse the risk of heart disease.

The new measurement has the advantage of not requiring pre-test fasting, unlike tests for HDL and LDL cholesterol.

Typically, doctors refer only to the LDL levels in a person's body as an indicator of their heart disease risk. Now, however, scientists have discovered that looking at the ratio of two proteins that carry cholesterol in the blood is a much more sensitive and useful tool for predicting cases of heart disease.

The two proteins, apoB and apoA-1, serve related but distinct functions. ApoA-1 carries HDL or “good” cholesterol through the blood, while apoB transports “bad” or low-density cholesterol.

By calculating the ratio of apoB/apoA-1 in the blood, scientists derive a score that indicates the balance between bad cholesterol particles that speed up hardening of the arteries and good cholesterol particles that work against that same process. Elevated levels of apoB and apoA-1 were detected up to twenty years before heart disease onset, making this measurement an exceptionally sensitive and potentially useful one.

Scientists from the Karolinska Instituet in Sweden carried out the study over the course of 30 years. They followed more than 137,000 Swedish adults between the ages of 25 and 84, measuring the apoB/apoA-1 values in patients’ blood to generate a risk quotient score. During the course of the study, 22,000 patients experienced some kind of major adverse cardiac event like a heart attack.

Looking at the ratio of two proteins that carry cholesterol in the blood is a much more sensitive and useful tool for predicting cases of heart disease.

A high-risk quotient was associated with a 70 percent increased risk of heart disease or major cardiac event compared to those with the lowest scores. Those with the highest risk scores also experienced heart disease many years earlier than their counterparts with lower scores.

“The results show that the higher the apoB/apoA-1 value, the greater the risk of myocardial infarction, stroke and need for coronary surgery,” Göran Walldius, lead study author and professor of epidemiology at the Karolinska Institutet, said in a statement, adding that the study results indicate that this risk was even greater in the presence of low protective levels of apoA-1. This means that low levels of apoA-1 increase the risk score as well as high levels of apoB.

Researchers hope that this new measurement can be used to identify patients at risk for heart disease long before their LDL levels become elevated.

This new measurement has the advantage of not requiring pre-test fasting, unlike tests for HDL and LDL cholesterol. The analysis methods are cheap and easy to carry out, another reason why researchers are encouraged about the usefulness of this measurement in the clinical setting.

Taking care of your own heart’s health is a matter of living a healthy lifestyle overall. In addition to getting regular blood work to check the levels of HDL and LDL in your blood, leading an active lifestyle, not smoking, eating a varied diet rich in plant foods low in saturated fats are all ways to build a healthy heart that will serve you well for decades to come.

More information about this study is available in the journal PLoS Medicine.