The finding, by researchers at the University of Otago’s Christchurch campus, could eventually help doctors to identify people whose lives could be saved from a future heart attack by preventive measures.
"It will be a useful tool for early detection of cardiovascular disease," lead researcher Tim Prickett said yesterday.
Dr Prickett, of the Christchurch Heart Institute, hoped the new test would soon be widely adopted.
Institute researchers studied the blood samples and cardiology scans of 665 healthy young and middle-aged people.
In a world-first discovery, they found people with high levels of a blood hormone, called C-type Natriuretic Peptide (CNP), were more likely to have stiffening of the arteries, reduced pumping action of the heart, and higher fat levels in the blood and liver - all signs of higher heart disease risk.
The study was the first to describe a link between this hormone and tissue inflammation, including of the arteries and heart.
The results were recently published in the international Peptides journal.
Dr Prickett said CNP seemed to protect arteries from hardening and blocking. This meant the hormone was present in higher levels in people with potentially poor, and undetected, cardiovascular health.
Researchers examined two groups of healthy people - one aged 28 and the other aged 50, both without a history of heart or kidney disease.
High levels of CNP in both groups were found in people with stiffer arteries, reduced pumping action of the heart, and higher fat levels in the blood and liver, he said.