The world's life expectancy has been gradually rising over the last century. In 1900, the average human life expectancy was just over 47 years. Today, that number well exceeds 72 years, a 25-year, 53% increase. Longer lifespans have greatly affected human culture, opening up more possibilities and alleviating some the anxieties of heedlessly squandered years. However, despite improved healthcare and resources, humanity is still plagued by a number of diseases and other lethalities.
By tracking the leading causes of death over a controlled population, federal health systems can strategize against the factors that are killing their citizens. Morbidly, however, access to these statistics is something of a privilege, and it is not uncommon for low-income countries to have to make estimates due to incomplete figures or incorrect diagnoses.
The leading causes of death in the world in millions (2017):
The leading cause of death in the world for countless years running is heart disease. In 2017, heart disease accounted for nearly 32% of the world's total deaths. Heart disease accounted for almost twice as many deaths as all Cancers combined. While this list above functions as a comprehensive overview of the causes that are afflicting humanity as a whole, it is productive to compare the leading causes of death between high-income and low-income countries. Additionally, it's important to note the contrast between countries that have a high median age to those that have a low median age.
The term high-income is sometimes substituted with the term "First World". In 2020, this classification refers to countries where the gross national income (GNI) is greater than $12,536 per year. GNI is an alternative to GDP that calculates the income of a country's citizens and businesses per capita as opposed to the country's productive output. Liechtenstein has the world's highest GNI at $116,430.
In high-income countries, the life expectancy is around 80 years, 18 years higher than in low-income countries. Japan has the highest life expectancy in the world at just over 85 years. Not so coincidentally, Japan also has the world's highest median age at 47.3 years old (with the exception of Monaco's 53 which has just 38,682 residents).
The longevity of these countries is reflected in their leading causes of death. In high-income countries, the leading causes of death are almost all non-communicable diseases, particularly ones that are prone to affecting humans more severely as they age. A non-communicable disease is one that cannot be transmitted directly from one person to another.
The leading causes of death in high-income countries per 100,000 citizens:
The term low-income is sometimes substituted with the term "Third World" and refers to countries where the GNI is less than $1,026. The country with the lowest GNI is Burundi, where it is just $280. If the current figures persist, it would take a Burundian 416 years to earn the same amount that Liechtensteiner earns in one.
The average life expectancy in low-income countries is around 62 years, considerably less than that of high-income countries. The country in the world with the lowest life expectancy is the Central African Republic, where a person can expect to live only 53 years. One factor of these statistics is the rate of child and infant mortality in low-income countries. Up to one in fourteen children living in one of these nations dies before their fifth birthday.
The leading causes of death in impoverished nations tend to pertain to lack of access, timely healthcare, or sufficient resources. The consistent leading causes of death are communicable (transmittable) diseases, pregnancy and neonatal complications, and issues related to malnutrition.
The leading causes of death in low-income countries per 100,000 citizens:
It's clear that many of the leading morbidities in low-income countries are preventable. One troubling observation is that low-income countries often coincide with the countries that are growing the most rapidly. For example, Niger in Northwestern Africa has the fastest growing population in the world, increasing at a rate of 3.8% per year. With the world's lowest median age of 15, the population of Niger is projected to triple by 2050, and yet it ranks 183rd in GNI per capita.