This week the Royal Swedish Academy of Sciences awarded the Nobel Memorial Prize in Economic Sciences to Angus Deaton "for his analysis of consumption, poverty, and welfare." Last year Professor Deaton and nine other distinguished economists offered their visions of the future in In 100 Years. In the following excerpt from the book, Deaton predicts the future of health.
American life expectancy has increased by about thirty years since 1900, though the annual rate of increase before 1950 was about twice as fast as the annual rate of increase since 1950. At the same time, life expectancy gaps between the rich and the poor world have narrowed. If we were to use some compound of life expectancy and income as a welfare measure—for example, per capita income multiplied by life expectancy—overall growth in rich countries has been slowing even faster than income growth alone, and poor countries have been catching up with rich countries. Or at least they were catching up except for those affected by HIV/AIDS, and we might hope that those countries will catch up again once the epidemic is controlled.
The slowing in the rich countries, and the catching up of the poor with the rich, are both mechanical features of life expectancy. Life expectancy is a convenient but essentially arbitrary measure of population health, and it gives much higher weight to deaths of children than to deaths of adults. So the decelerating growth in life expectancy cannot be taken to mean that the decline in all mortality rates is slowing down or that all mortality gaps between poor and rich countries are narrowing. As for the future, the slowing down in the rate of growth of life expectancy cannot be taken as a sign of things to come. There are real threats to future mortality decline— whether HIV/AIDS is controlled is one—but the deceleration of life expectancy is not one of them.
In both rich and poor countries, life is riskier in early childhood and in old age, with little risk of death in adulthood. But in poor countries today, as in rich countries in the past, the chance of dying in the first few years of life is much higher than it is in rich countries. About 50 out of every 1,000 children born in India die in their first year, close to the fraction who died in Scotland in the year that I was born (1945). In 2010, fewer than 4 out of every 1,000 infants died in Scotland, the lowest figure ever recorded and one of the lowest rates in the world. In rich countries today, death stalks the elderly. In rich countries in the past and in poor countries today, death stalks the young. In poor countries today, as in rich countries in the past, progress comes from reducing mortality among children. In the rich countries today, progress comes from reducing mortality among adults.
The first health improvements came (and in some places are still coming) from better public health—such things as clean water, sanitation, vaccination, and the elimination of pests that cause disease. These things can bring rapid falls in infant and child mortality, and life expectancy zooms upward. Once those “easy pickings”—at least for life expectancy—are gone, health improvements have to come from reducing adult mortality, which means reducing heart disease and cancer. There has been enormous progress in rich countries in reducing mortality from heart disease, and many middle-aged and elderly lives have been saved. This kind of progress does much less for life expectancy than progress in reducing mortality among children.
We can argue either way about whether the life of a newborn is worth more or less than the life of someone in middle age or someone in old age, but there can be no automatic presumption in favor of the simplistic view that saving more years of life is always the best thing to do. The slowdown in the rate of improvement of life expectancy is essentially a measure of success, not of failure. In the rich countries, we have largely disposed of the early life killers, which are the ones that have the big effects on life expectancy and have moved on to the next killers, which strike at older ages.
The real question for our grandchildren and their grandchildren is whether the progress in mortality reduction can be expected to continue. Once again, the sky is not entirely clear, but I believe that the answer is yes.
The current reduction in mortality from cardiovascular disease still has some way to go. Antihypertensive drugs are cheap and effective but require patients to have their blood pressure regularly checked by a physician, something that many people do not do. There are many lives here that can be cheaply saved. Smoking rates have come down among men and, with a lag, among women, so that the gap in life expectancy between women and men is now smaller than it has been for many years. If women continue to quit as men have done, many fewer of them will die from cardiovascular disease and lung cancer.
What about cancers other than lung cancer? The most important are breast cancer (primarily among women), prostate cancer (entirely among men), and colorectal cancer (among both men and women). In very recent years, serious progress has been made against all three of these cancers, driven by a combination of screening and new drugs, some developed in the traditional way, by trial and error, and some using new scientific advances in understanding how cancer works. Unlike mortality reduction through antihypertensive drugs, giving people aspirin after a heart attack, or smoking reductions, these treatments are expensive, and their widespread use could be limited by lower growth rates of income should those come to pass. But many scholars believe that over the next fifty years, we will see the progress against cancer that we have seen in the past fifty years against cardiovascular disease.
One of the deep reasons that health will continue to improve is that people want it to improve and are prepared to pay for the innovations, basic science, discoveries about behavior, drugs, procedures, and devices that support it. Innovations cannot be bought off the shelf and do not always come along when they are needed. But there is no doubt that urgency helps. As each disease is conquered, the next becomes the main target; no one cared about Alzheimer’s when a quarter of the population did not reach its fifth birthday. But as life expectancy increases, these later-life diseases become priorities, and as people get richer, they will devote larger and larger shares of their incomes to dealing with them, so that spending rises faster than national income.
In poor countries, infant and child mortality remains a major curse, even if there has been enormous improvement over the past half-century. The children who die in these countries would not have died had they been born in rich countries, and to that extent, we should be able to prevent their deaths. They are not dying from incurable exotic diseases but from respiratory infections, diarrheal disease, and vaccine-preventable diseases, all of which have been eradicated among children in rich countries. So the potential for progress is enormous. Some will come through more widespread education, particularly of women, which brings a wider understanding of the germ theory of disease and its implications, like the need for hand-washing and for clean water.
The major roadblock here is not the availability of medicines, many of which are cheap and readily available, but the capacity of many governments to develop a system of maternal and child care that will bring known remedies to these children and their mothers. Much will depend not so much on economic growth in poor countries—China did much better in reducing child mortality before it began to grow, and the same is true in India to a lesser extent—but on improvements in state capacity and state commitment.
Apart from sub-Saharan Africa, most deaths in the world today are from noncommunicable diseases such as heart disease and cancer, not from the infectious diseases that have been the primary enemy for much of human history. As we have seen, cardiovascular disease mortality has fallen rapidly in rich countries and has done so based on cheap drugs and on smoking reduction. While the new cancer treatments may be difficult for public health authorities to afford in many nonrich countries, cost is not a consideration for aspirin or for diuretics, and we can expect to see a spread in treatment rates from both public and private providers around the world. Again, the constraint may be the rate at which adequate physician-based health systems can evolve (public sector) and be regulated (private sector). The outlook for smoking rates in poor countries is less positive, if only because rising incomes will work to increase smoking and because tobacco companies are targeting consumers in some middle-income countries.
Even HIV/AIDS, which has wiped out the life expectancy gains of the past fifty years in several countries in Africa, is being tackled by the provision of antiretroviral drugs. Between 2003 and 2010, the number of people receiving these drugs in poor countries increased from under 3 million to more than 10 million. With luck, the epidemic will be history long before the century is up.
There are links from income growth to health improvements; better nutrition comes with more money, public health projects (water and sanitation) cost public money, and the pressure for innovation is both fueled and financed by rising living standards. Yet it is a mistake to think that income and health always march together. Catch-up health improvements, like catch-up growth, require modest innovation—more in process than in concept—and historically there have been many occasions where there were massive reductions in mortality—through antibiotics, water provision, and mosquito control—in places where living standards were stagnant. Policy matters too. When China decided to encourage rapid economic growth in the mid-1970s, it turned away from the public health measures that had been a successful part of the previous regime. When thinking about the future, we must not suppose that everything depends on economic growth, so that even if growth falters, there is nothing that guarantees it will bring down health with it.