Heart Disease is the Leading Cause of Death in Australia—Here’s Why

Genetics are also a contributor.

In 2020-21, there were 160,000 hospitalisations where CHD was recorded as the principal diagnosis in Australia. Jo Panuwat D/shutterstock

Coronary Heart Disease (CHD)—which is the narrowing or blockage of blood vessels that supply blood to the heart—is the “leading single cause” of disease burden and death in Australia, with many risk factors easily preventable by adopting healthier lifestyles.

In 2020-21 alone, there were 160,000 hospitalisations where CHD was recorded as the principal diagnosis, which is equivalent to 1.4 percent of all hospitalisations, and 27 percent of all cardiovascular disease (CVD) hospitalisations in Australia, according to data from the Australian Institute of Health and Welfare (AIHW).

Additionally, males were 2.5 times as likely as females to present to the hospital for CHD.

Yet despite most Australians knowing that improving diet, exercise, and weight loss can improve heart health, the prevalence of risk factors such as high blood pressure, high cholesterol, being overweight or obese, and physical inactivity are still relatively high, according to the Heart Foundation.

While these measures are common knowledge, what may not be well known is that genetics can also contribute to CHD.

Genetic Causes of CHD

According to an international team of scientists, 11 genes were found to contribute to the hardening of the heart’s arteries. Eight of these genes were not previously identified, and were found to play a role in coronary artery calcification.

The calcification or hardening of the heart’s arteries occurs over many years and stems from a buildup of fatty plaque.

Calcification results in the narrowing or blockage of the arteries, which can impair the heart’s blood supply; this can then affect the heart’s ability to pump blood, oxygen, and nutrients around the body, and it can cause a heart attack if a piece of the calcified plaque breaks off.

Another gene called “Phosphatase and actin regulator 1 (PHACTR1)” was also found to play a big role in the calcification process.

PHACTR1 is known to be a major driver of Spontaneous Coronary Artery Dissection (SCAD) heart attacks—a rare but serious condition that occurs when an inner layer of one of the blood vessels in the heart tears. Blood then seeps between the artery layers, forming a blockage that can slow, or block blood flow to the heart and cause either angina, a heart attack, abnormalities in heart rhythm, or sudden death.

PHACTR1 is also known to cause fibromuscular dysplasia, where the artery walls become too weak or too stiff, and affects 1 in 20 Australian women.

One of the study’s authors, Professor Jason Kovacic, CEO and director of the Victor Chang Cardiac Research Institute, said understanding the biological mechanisms was important for developing new treatments to decrease CVD risk.

“Coronary heart disease is by far the most common heart disease affecting Australians. It is the biggest driver of heart attacks so if we can get in early and stop its progression in the first place, we could save tens of thousands of lives each year,” Mr. Kovacic said in a study.

The study was the largest such meta-analysis conducted to date that sought to understand the genetic basis of coronary artery calcification.

What made this study unique was that it contained a large proportion of participants of non-Caucasian backgrounds, including 8,867 individuals of African ancestry. In total, scientists analysed data from more than 35,000 people.

According to the Victor Chang Cardiac Research Institute, the study can now help scientists develop drugs or repurpose existing ones that can target the genes or encode proteins to modulate the calcification process.

“That could be a game-changer for treating a disease responsible for more than 17 million deaths annually around the world,” the Institute said.

Preventing Coronary Heart Disease Through Healthier Lifestyles

The Heart Foundation has said that Australians “could do more” to prevent CHD, and recommended being active for five or more days each week—totalling 2.5 hours per week—eating five or more vegetables per day, controlling blood pressure, not smoking, and reducing alcohol intake.

Additional tips from the Victor Chang Cardiac Research Institute include:

• Maintain a healthy weight and lifestyle
• Follow a healthy diet
• Exercise for 30-60 minutes to get your heart rate up, five times per week
• Walk everyday
• Know your family history and get regularly tested
• Manage your cholesterol, blood sugar, and blood pressure levels.
• Adults should aim for seven to nine hours of sleep per night.