The silent march of progress against death

The miracle of falling mortality rates and what it tells us about the nature of progress.

The world can seem like a dangerous place. Wars and crimes dominate the news headlines. Yet, statistics tell a very different story. Globally, around 200,000 people die from conflicts each year, which is less than the number of deaths due to atrial fibrillation, or irregular heartbeats. When displayed among all causes of human deaths, violence barely registers. Simply put, we are much more likely to die from germs and genetic mutations than in the hands of another human being.

The good news is that the likelihood of dying from diseases has steadily reduced year after year. 2020 and 2021 saw a spike due to COVID-19, which has fallen significantly in 2022 and 2023. Nevertheless, even in 2021, the age-standardised mortality rate from all causes was 25% lower than it was in 1990. It’s one of the modern miracles that despite processed food, environmental degradation, stress, and poor lifestyles, the chance of surviving into the next year just keeps getting better. Furthermore, this progress is seen across many disease areas. In the graphs below, I have plotted the mortality rates of major noncommunicable and infectious diseases using the data from the Global Burden of Disease Database.

What drove the almost universal declines in mortality rates across multiple disease areas? Medical advances seem like the obvious place to start. The previous decades have seen numerous medical breakthroughs. Some are relatively cheap and low-tech, such as oral rehydration therapy for cholera, vaccines for tuberculosis and smallpox, and statins for reducing cholesterol; while others, like gene therapies and minimally invasive heart surgeries, are incredible scientific achievements. Together, innovation in the prevention, diagnosis, and treatment of diseases has saved the lives of millions of people every year, enabling them to live longer with loved ones.

However, medical advances are not the only reason for us living longer and might not even be the main contributor. The graph below shows the median survival age for people with cystic fibrosis, a genetic disorder that causes sticky mucus to build up in various organs, primarily affecting the lungs and digestive system. It’s a terrible disease, and until 1970, most cystic fibrosis patients didn’t survive into adulthood. Like many diseases, the survival rate for cystic fibrosis has been improving, but the remarkable thing is that this improvement predated the launch of the first drug that treated the underlying cause of cystic fibrosis. That drug, developed by Vertex Pharmaceuticals and The Cystic Fibrosis Foundation, was only launched in 2012. Yet, the survival rate for cystic fibrosis has been rising for more than five decades by then. An important factor behind this is better knowledge and education, which allowed doctors and carers to better manage the disease’s symptoms and reduce the chance of complications.

English physician and medical historian Thomas McKeown argued that effective treatments played a minor role in improving healthcare outcomes. He drew a series of graphs that showed declining mortality rates long before the advent of effective treatments. McKeown argued that the improvements in the material living conditions, such as housing and food, played a much more important role. My own take is that for infectious diseases, the McKeown Thesis is valid because the living environment plays an important role in the spread of disease. However, for non-communicable diseases, treatments will play an important role.

The McKeown Thesis highlights an important point: economic growth plays an important and often under-appreciated role in human progress. Whether it’s in healthcare, education, or even how we treat those who are less privileged or from different backgrounds, the likelihood of a positive outcome is much higher when we have a growing and prosperous economy.