A seaside scene in Indonesia. As countries like Indonesia move up the income ladder, some health conditions improve — but new threats, like non-communicable diseases, loom large.

A seaside scene in Indonesia. As countries like Indonesia move up the income ladder, some health conditions improve — but new threats, like non-communicable diseases, loom large. / Tommy Trenchard for NPR

What are the biggest drivers of human suffering?

Every year an international team of researchers aims to answer that question by assembling a mammoth data set called the "Global Burden of Disease." It has become the go-to source for tracking and ranking the impact of virtually every disease or condition that is killing, sickening or otherwise disabling people in virtually every country on the planet.

But this year's report also points to some intriguing solutions — highlighted by the researchers in a piece published this week in the medical journal The Lancet that accompanies their latest data release.

To learn more, NPR spoke with the scientist who leads the project, Christopher Murray of the University of Washington's Institute for Health Metrics and Evaluation. Here are three takeaways:

1. The key to health is ... wealth. (And education ... and women's rights).

The Global Burden of Disease doesn't just comprise data on health. The researchers also pull together and analyze measures of economic and social wellbeing over time — including each country's per capita income, average educational attainment and status of women (as reflected by the typical number of children a woman there gives birth to).

And on these socioeconomic fronts, the researchers find that since 2000 the worst-off countries have made enormous strides. "The bottom 20% of countries are catching up. They are now developing at a faster rate than the countries at the top," says Murray.

Over this same period the poorest countries also saw major gains on what's called "healthy life expectancy" — or as Murray puts it "how many years you can expect to live in full health."

And here's the kicker: Through statistical analysis, Murray and his collaborators were able to show that nearly all of this rise in healthy life expectancy was the direct result of the gains in income, education and women's status.

For instance, between 2000 and 2019, for countries on the absolute lowest end of the socio-economic scale, healthy life expectancy increased by 9 years. And nearly 80 percent of that increase could be explained by their socioeconomic progress during that same time frame.

One caveat is that the link was far less pronounced for countries on the higher end of the socioeconomic scale. But for poor ones the lesson seems clear, says Murray: One of the most effective ways to boost people's health is to focus on advancing their social and economic development.

2. We need to pay more attention to "non-communicable" diseases.

As impressive and laudable as the health gains in poor countries have been, one downside is that they are concentrated in just four types of diseases: communicable, maternal, neonatal and nutritional.

This is not surprising, says Murray. The problematic conditions that enable these diseases to thrive tend to fade as a country gets richer and more educated and affords its women higher status.

For instance, says Murray, "as soon as people and societies have more resources they tend to deal with water supply and sanitation. Also basic malnutrition starts to go away." Both factors play a key role in how many of a country's children contract infectious diseases that kill them before the age of 5.

Indeed, one of the best outcomes of the last 20 years has been that the annual number of deaths among children below age 5 dropped from 9.6 million in 2000 to about 5 million in 2019.

Unfortunately, says Murray, many of the drivers of different category of illness — known as "non-communicable diseases" — actually tend to get worse as countries start to move up the socio-economic scale.

Take air pollution — which is linked to lung cancer and other respiratory ailments. "You know, if you're in a preindustrial society, there's not a lot of air pollution," says Murray. "As societies industrialize it tends to get worse."

Other risk factors that worsen as countries develop include the incidence of obesity, high blood sugar and high blood pressure — which are variously linked to diabetes and heart disease.

The result is that the gains that poor countries have made against that first category of diseases — communicable, maternal, neonatal and nutritional — over the last 20 years has not been matched by progress in addressing non-communicable diseases. So now, non-communicable disease cause a far greater share of the health burden that low- to middle-income countries face. Specifically, between 1990 and 2019 non-communicable diseases went from contributing about 40% of the health burden to 66%. (The Global Burden of Disease project measures health burden as the number of healthy years of life that a country loses to disease each year.)

Unfortunately, many countries and health systems are still set up as if the biggest source of poor health are communicable diseases. "Because of the way people are trained, governments are very often focusing on the problems of the last generation and not the current one," says Murray.

"Take a place like Indonesia," he adds. "It's really just dramatic. Now more than 80% of the health burden there is non-communicable diseases. But [those] are not the main focus of policy formulation. They're still worrying about the previous problems."

India is another example, says Murray. "They have a huge problem with high blood pressure, and there should be a national strategy for getting more people into primary care and getting their blood pressure treated," he says. And yet, "they don't really have a national blood pressure strategy."

3. Preparing for the next pandemic ... could mean taxing soda pop.

Any national strategy aimed at non-communicable diseases would need to address behaviors by both individuals and corporations, says Murray. That's because many of the risk factors involved are related to decisions by corporations — what do they put in our food — and our own choices regarding what (and how much) we consume and how much we exercise.

Murray suggests taking lessons from the one success story governments can point to when it comes to curbing a risk factor for non-communicable disease: smoking. "We found that regulatory and taxation strategies have made sustained progress [on smoking] over the last decades," says Murray. After all, the more inaccessible and expensive tobacco is, the less people are likely to use it.

It can be hard to build support for regulatory approaches — just look at the pushback against taxes on sugary beverages in many countries. But Murray says it may help to consider these strategies not only as efforts to address non-communicable diseases but as a vital element of the world's strategy for preparing for the next pandemic.

Before COVID-19, he says, the health experts who specialized in infectious disease and pandemic readiness "lived in separate universes." Then, he says, "suddenly COVID-19 comes along and we find out that obesity and blood pressure are key determinants of what your risk of death from COVID is. And it highlights how we have older populations and more of these risk factors and we are creating far greater vulnerability."

As worrisome as those risk factors may sound says Murray of this year's report: "I think these are an empowering set of findings. There's plenty of things that we identify where governments and individuals can take action."

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Tags: communicable diseases  global burden of disease  non-communicable diseases  optimism