Heart diseases, also known as cardiovascular diseases (CVDs) are the number 1 cause of death around the world. In 2016 alone, 17.9 million people died from CVDs, accounting for 31% of deaths globally, with 85% of these having been due to a heart attack or stroke. But why is this? Why is heart disease the world’s leading cause of death?

Just 120 years ago, at the turn of the last century, CVDs were considered a relatively minor disease. So what has happened in the last 120 years to make it the world’s biggest killer? As it turns out, a lot of this may be due to improved public health measures and general medical care. For example, back then, antibiotics and vaccines as well as general knowledge on preventative care were not as widespread as they are today, meaning that pneumonia and flu could take centre stage as a leading cause of death, followed by tuberculosis and digestive disease.

Thus, in many ways, the explosion of CVD deaths per year comes as other killer diseases and conditions are just better avoided. However, how does it play out on a more macro level? When zooming out, it seems that CVD mortality rates correlate with economic, social and demographic forces.

An example of this is how during times of pestilence and famine, CVD tends to count for just 5-10% of mortality rates, with deadly forms of the condition being attributed to infection and malnutrition. Sub-Saharan Africa seems to be at this stage currently, wherein deaths from communicable diseases still far outpace those from more chronic diseases like CVD.

However, in times of increasing wealth and higher food availability, the causes behind CVD change, and its mortality rate tends to skyrocket. This comes as increased wealth allows for better nutrition and thus reduced infant mortality rates. This, coupled with general improvements in public health, then causes deaths from infectious diseases to decline, as we can see in some Caribbean countries as well as regions in Latin America, India and China.

Then, as improvements in economic circumstances combine with urbanization and changes the nature of work-related activities, dramatic changes in diet, activity levels and behaviors (such as smoking) start to proliferate more rapidly. Where degenerative diseases start to take centre-stage, cheaper, more plentiful and more nutritionally-dense foods (particularly in sugar and fat) increase caloric intake, while further mechanization means that people spend fewer calories in exercise. This then leads to higher body mass indexes, higher plasma lipid levels and blood pressure- key prerequisites for CVD. Such lifestyle changes thus mean that CVD becomes responsible for 35%-65% of all deaths, something that is currently visible in emerging market economies such as those in the former Soviet Union and areas of the Middle East.

The final phase of the transition however, which sees chronic diseases such as CVD and cancer as the main causes of death also coincides with technological advances to treat the conditions, such as coronary care units and thrombolytic therapy, and preventative measures such as smoking cessation and blood pressure management. Due to these factors, deaths are prevented or belated, meaning that CVD tends to affect older and older individuals while life expectancy creeps upwards and age-adjusted CVD mortality rates decline. This is where countries such as the US and those in Western Europe stand now.

To conclude, it seems that heart disease is the world’s leading cause of death largely due to improved medicine practices staving off death from other factors like infections, alongside lifestyle choices that encourage cardiovascular degeneration. Although preventative measures and better healthcare may belate it from taking hold, even in more advanced economies, it still keeps the bottom line in claiming lives, only perhaps increasingly in the guise of 'dying from old age’.





Sources: Medscape, European Society of Cardiology, PMC, WHO and Cleveland Clinic