Garry Jennings receives funding from the National Health and Medical Research Council. He is affiliated with Baker IDI Heart & Diabetes Institute, The National Heart Foundation, Alfred Health and Monash University.
Diseases of the heart and the vessels running to and from it are the number one reason people die in Australia, and we’re not alone. They are the number one cause of death in the world.
According to the Australian Bureau of Statistics, ischaemic heart disease (IHD) is the leading cause of death in Australia. In 2014, 20,173 people died from it.
But ischaemic heart disease is not really the disease itself. Rather, it is the term used to cover the clinical manifestations of coronary heart disease such as heart attacks and angina.
Coronary heart disease
Coronary heart disease is almost always a consequence of atherosclerosis. This is a build-up of cholesterol and other material in the walls of our arteries (tubes that carry blood and oxygen to the heart). The build-up can cause heart attack and block access to the brain, leading to stroke – another of Australia’s top killers.
Ischemia describes insufficient oxygen supply to the heart muscle. Lack of oxygen can cause discomfort in the chest, such as a tightness or squeezing known as angina. This is most often brought on by exercise but is more serious when it happens at rest.
Persistence of angina over time, particularly at rest, can lead to death of some heart muscle. This is called an acute coronary syndrome, or colloquially, a heart attack. We used to call this myocardial infarction. No wonder people find the terminology confusing.
The Australian Bureau of Statistics classifies ischaemic heart disease as the leading cause of death in Australia. Cerebrovascular diseases (stroke) are the third, heart failure is at number seven; hypertensive diseases are at 13, and cardiac arrythmias at 19.
But there is considerable overlap among these, which is why this article has combined them under one umbrella. Hypertension (high blood pressure), for instance, is a major cause of stroke and a risk factor for coronary disease. At least half of heart failure is due to coronary heart disease, while the most common cardiac arrhythmia (irregular heartbeat), atrial fibrillation, is often caused by hypertension, heart failure or coronary heart disease. Further, atrial fibrillation is the cause of about one-third of strokes.
Although ischaemic heart disease is responsible for 20,173 deaths in 2014, the number of deaths due to the above circulatory diseases in 2014 was 38,741.
History of heart disease
Heart disease is not new. CT scans of Egyptian mummies who lived 3,500 years ago show they had narrowings in their arteries, which means they had coronary heart disease. Pharaoh Merneptah, for instance, who died in 1203 BC, had severe coronary disease.
The real and documented epidemic of heart disease occurred after the second world war. This could in part be explained by higher rates of smoking, blood pressure and poor diets after and during the war. Rates increased for three decades at this time.
Then they fell; first in Australia and the United States, and then in other developed countries. Half of this fall could be attributed to public health measures such as tobacco control and availability of blood pressure and cholesterol treatments; the other half to better treatment of people with heart disease.
A province of Finland, North Karelia, initially held the dubious record for the highest rates of heart disease in the world. In the early 1970s, the region had around 672 per 100,000 people dying from heart disease. The mantle then passed to Eastern Europe and Russia where rates are currently 320 per 100,000 people. This is astounding compared to Australia where the rate is 54 per 100,000.
In 1990, heart disease was the third-highest cause of death in developing countries, but by 2013 it was number one. The rates rose from 70 per 100,000 people to 91 per 100,000 people in those years respectively. This is because the developing world acquired the habits of the developed world. There are now more people in the world who are overweight than underweight.
Hypertensive diseases are rising in most developing countries, together with diabetes, while smoking remains common. Infections and trauma used to cause death in people too young to have heart disease, but that is no longer the case due to antibiotics, immunisations and better safety standards.
In 1990, there were 12.3 million deaths globally from heart disease. By 2013, this had risen to 17.3 million. Most of this 40.8% increase occurred in developing countries and in disadvantaged people in developed countries like Australia.
Every country in the world is at some point in the transition from low to high to medium rates of heart disease related to their stage of development. There is nothing inevitable about heart disease being the number one cause of death in Australia or the world as a whole.
The stereotype of a harassed executive having a heart attack no longer applies. Heart disease has become a blue-collar disease or one seen initially in urban populations in developing countries.
Where to from here?
Today (and for the foreseeable future) global rates of heart disease are driven by development, inequality and prosperity. The rate of heart disease deaths was almost double for Australians in the lowest socioeconomic group compared to the highest socioeconomic group, and 20% more for those living in remote to very remote regions compared to those in major cities. They were 40% higher for Indigenous Australians compared to their non-Indigenous counterparts.
For years, we have been comforted by falling rates of heart disease deaths in Australia. But as the population increases, ages and people survive diseases such as cancer earlier in life, the burden on the health system has not been falling to the extent that rates would suggest.
Alarmingly, in people aged 55-69 both rates and the absolute number of people dying from heart disease have increased, according to the latest data.
As Australia has become one of the fattest nations in the world, with rates of diabetes increasing and other metabolic consequences leading to heart disease, overweight and sedentary men and women with multiple risk factors have replaced the thin male smokers who died of heart disease in the 50s.