The leading killers of human beings are no longer the viruses, bacteria and other microbes that have lurked for millennia in our sewage, in our domesticated animals and in the parasites that bite or burrow into us. For the first time in recorded history, non-communicable diseases, such as cancer, heart disease and stroke, are the leading cause of death in every region of the world. That includes Africa.
This is a remarkable, largely unheralded, achievement. It brings important and little-understood challenges.
In 2011, infectious diseases stopped being the leading cause of death in Africa. By 2015, only 44 per cent of African deaths were the result of diseases such as dysentery, pneumonia, malaria, tuberculosis and HIV. That is still high. In most regions of the world, infectious diseases account for less than 10 per cent of deaths.
Still, the rate of decline in Africa has been the most rapid in history, with deaths in recent decades falling at three or four times the pace they did in advanced nations. Africa is undergoing a warp-speed health revolution.
As infectious diseases fall, non-communicable diseases naturally rise. In 1990, only 25 per cent of people in poor countries died from conditions such as diabetes, hypertension and cancer. In 2040, that will increase to 80 per cent in many of the same nations.
The rise of non-communicable disease is partly explained by the fact that people are living long enough to succumb to such afflictions. But this is not the whole explanation. Many people in poor countries are contracting non-communicable diseases at younger ages than in rich countries. The risk of early death from heart disease, diabetes and other afflictions commonly referred to as “diseases of affluence” are, in reality, becoming diseases of poverty.
A remarkable new book from which these data are mined, addresses these issues. Plagues and the Paradox of Progress by Thomas Bollyky, argues that poor countries are struggling with the consequence of their success.
That is because infectious disease in poor countries has been combated largely through medicine and international assistance. This is not how it happened in advanced nations. In US cities between 1900 and 1936, a 43 per cent decline in mortality resulted from water filtration and chlorination. Better sanitation and housing, improved education and quarantine all had an impact before sophisticated medicines arrived.
Poor countries are achieving the same results earlier — often without the institutional changes undertaken in the US and elsewhere. “The heavy burden of plagues, viruses, and parasites is being overcome in the cities of many lower-income nations without effective housing laws, adequate municipal water and sewage systems,” writes Mr Bollyky.
Killer diseases in children have plummeted. But too often the result is more sick adults living without adequate health systems or employment opportunities. A 15-year-old in a low-income country has the same life expectancy today as in 1990; dramatic average gains in longevity have occurred as a result of averting childhood deaths.
There are several implications. First, poor countries need to devote more resources to preventing and treating non-communicable diseases. Africa’s elite too often opts out, seeking treatment abroad. Those who stay at home receive limited care at best.
Africa is urbanising at a staggering pace. Crowding unhealthy people into unprepared cities is a recipe for more sickness. Urban planning of the sort undertaken in the US before the age of penicillin is essential. Foreign aid also needs recalibrating. Four diseases — cancer, upper respiratory conditions, heart disease and diabetes — account for 60 per cent of deaths globally. In a few decades, this will be the picture in countries from Bangladesh to Burundi. Yet only 1 per cent of health-related development assistance goes to non-communicable diseases.
Poor countries also need to crack down on killers such as pollution and tobacco. In 2013, Namibia, Togo and Uruguay tried to restrict cigarette advertising, but were warned off by Big Tobacco. Governments should unite to face down cigarette companies and other purveyors of unhealthy lifestyles.
Tilting the emphasis towards the killers of today does not mean easing up on those of yesterday. Infectious diseases are here to stay. Higher temperatures, antibiotic resistance, rapid urbanisation and international travel are the friends of bacteria and viruses. Outbreaks of bird and swine flu in China, the Zika virus in Latin America and Ebola in Africa hint at coming plagues.
Yet fighting viruses and parasites must not blind the world to the evolving challenge. As Mr Bollyky writes: “The story of the decline in infectious diseases threatens to be as consequential as the history of their rise.”