本文作者桑德罗·加利亚是波士顿大学公共卫生学院院长、Robert A. Knox讲席教授。他的新书《更健康：关于人口健康基石的50个想法》（Healthier: Fifty thoughts on the foundations of population health）将于今年6月出版。
In 1947, Dylan Thomas composed his most famous poem, “Do not go gentle into that good night,” exhorting the reader to resist the end of life. “Rage, rage against the dying of the light,” Thomas wrote. Seventy years later, this sentiment infuses much of America’s investments in medicine. The US spends far more on health than any economically comparable country, with much of that money going towards healthcare for older Americans. In 2012, those over 65 years old spent an average of $18,988, which is more than five times the expenditure per child, and about three times the expenditure per working-age individual. This investment feeds into the broader trend of US health spending, which, in 2015, grew 5.8%, amounting to $3.2 trillion total.
Within the context of this enormous investment, we have seen the rise of a number of initiatives geared towards adding years to our lifespan, often leveraging genomics and pharmaceutical innovations toward this goal. Silicon Valley tech leaders, for example, have expressed a desire to “solve aging” and “hack the code of life,” enthralled by the possibility that, with the right technology, there may be no limit to how long we can live.
This week at Fortune’s Brainstorm Health conference, I will talk about the human quest for longevity viewed through the lens of population health. What follows is a preview, of sorts, of the thoughts I will be presenting there.
Life expectancy has increased significantly in the last century. In 1900, US life expectancy was about 47. It is now about 79. However, these gains were largely due to public improvements in nutrition and living standards precipitated by the Industrial Revolution, as well as to achievements in public health. Despite this remarkable progress, we are in the midst of seeing diminishing returns with respect to life expectancy. However much we might wish it were otherwise, we cannot live forever. Indeed, 88% of Americans will die before the age of 94, and 98% of Americans will die before the age of 100. It is true that new treatments can help prolong your life, but only to a limited degree. A recent analysis of health technology assessment reports found new cancer drugs to be associated with increased overall survival by an average of just 3.43 months between 2003 and 2013. Further, less than 20% of new cancer drugs have been proven to contribute to a survival increase. Overall, potential survival gains due to genetic or pharmaceutical innovation peak at about age 100, then quickly decline until the age of 115, adding more weight to the conclusion that the human lifespan is fixed.
Given this reality, how can we make life better during the time we have? Just as changes in the world around us contributed to rising life expectancy in the 20th century, improvement of these same social, economic, and environmental conditions can contribute to wellbeing in the 21stcentury. In a city of a million residents, for example, we could save $216 million in health costs through a 40% expansion of transit developments. We could double the quality of life for those living there by renovating housing according to green standards, improving ventilation, and reducing exposure to harmful chemicals. Early childhood education programs are associated with a benefit-cost ratio of 5:1, which means that for every dollar we spend on them we save five due to reductions in crime and teen pregnancy, among many other benefits. We could also do much good through progressive tax reform, especially by modifying the Earned Income Tax Credit (EITC). Each time the EITC has been raised by 10%, infant morality in the US dropped by 23.2 per 100,000 children.
Taking these steps would go far towards building a world that generates health. We have embraced similar measures in the past, to significant effect. In the US, we now travel more miles by road than ever before, yet in the years between 1925 and 1997, the nation decreased the number of motor vehicle deaths from a rate of 18 deaths per 100 million vehicle miles traveled to 1.7 deaths per 100 million miles traveled. The U.S. achieved this reduction by introducing legal disincentives for unsafe driving, promoting seatbelt use, and building safer roads. In short, we have improved health by changing the context around driving, minimizing hazard. It is worth noting that we did very little to improve the actual driver himself — rather, we changed the world around him, making us all safer.
This has particular importance for how we think of creating a better world. Even those of us who are lucky enough to have money and resources cannot buy ever-greater health and longer life in a society that neglects the conditions around us that determine wellbeing. Up to 56,000 people have died from the flu since 2010, a disease that is largely preventable through vaccines. Whether or not we get the flu depends as much on what those around us do as it does on our own actions.
In the area of dental health, risk of cavities increases by 15% for the 100 million Americans who do not drink fluoridated water. How many of us know whether we are drinking sufficiently fluoridated water? And our risk of becoming obese increases by 57% if we have a friend who becomes obese. How many of us choose our friends based on whether or not they are obese? The world around us therefore affects our health, whether we like it or not. It is simply not possible to buy our way out of the social networks and political policies that shape our wellbeing and our longevity, making this our shared issue.
In his poem, Thomas writes of the sense of regret and missed opportunities that can accompany the end of life. It is not to the uncertain future that his characters who “rave at close of day” look, but to the unfulfilled promise of the past — the quality of their years. What counts, in the end, is the richness of our lives, and the extent to which our time was healthy, and linked—from childhood to old age—to the community around us. To make this kind of life accessible to all, we must not miss our chance to invest in a culture that facilitates health throughout life.
Sandro Galea is the Robert A. Knox Professor and Dean of Boston University School of Public Health. His also author of the forthcoming book, Healthier: Fifty thoughts on the foundations of population health, which will publish in June.