Why We Are Living Longer

This post is a review of Unexpected Life: A Short History of Living Longer by Steven Johnson.

Over the last century, the life expectancy of human beings has doubled, due largely to a dramatic decline in childhood mortality. And, despite skyrocketing inequality within Western nations, the gap in life expectancy between developed and developing countries has narrowed considerably.

Source: istockphoto/pixabay

Breakthroughs in medicine get — and deserve — considerable credit for our increased longevity. They include the pasteurization of milk (which became standard practice in the industry in 1915), Robert Koch’s identification of the tuberculosis bacterium, the discovery of penicillin by Alexander Fleming, and treatments for AIDS.

Steven Johnson reminds us, however, that the removal of what Thomas Jefferson called a “catalogue of evils,” would not have occurred without non-medical initiatives.

In Unexpected Life, Johnson, the author, among other books, of Where Good Ideas Come From, How We Got To Now, Farsighted, and The Ghost Map, provides an informative and engaging account of how “the adjacent possible” led to the implementation of scientific discoveries, the lateral effects they created, and new ideas. A celebration of heretofore unsung heroes, collaborative networks, and institutions, his book is a timely analysis of progress in public health.

Reliance on data to combat epidemics, Johnson reveals, is fairly recent. A “compiler of abstracts” for England’s General Register Office in the middle of the nineteenth century, William Farr created a classificatory scheme for causes of death, broken down by age group and residence (metropolitan London, industrial Liverpool, rural Surrey). His studies “marked a milestone in the emerging science of epidemiology.”

At the end of the century, in an empirical study of a black neighborhood in Philadelphia that ushered in a discipline called social epidemiology, W.E.B. DuBois became the first person to document that African Americans were dying at much higher rates than whites and connect the disparity to an environment shaped by discrimination rather than moral characteristics of each race.

Testing medicines for efficacy is even more recent. Before 1938, the FDA was not empowered to investigate the safety of drugs sold in the United States. In the 1950s, two epidemiologists, Austin Bradford Hill and Richard Doll, developed randomized, controlled, double-blind trials and used RCT to investigate links between cigarette smoking and cancer. In the 1960s, following the thalidomide scandal, Congress authorized the FDA to require pharmaceutical companies to supply proof of efficacy in addition to safety. The partnership between RTC design and government regulation, Johnson points out, led to the elimination of dyes and rubbers connected to bladder cancer, reductions in road workers’ exposure to tars associated with skin cancer, and the outlawing of asbestos.

In a little more than a century, Johnson reveals, automobile accidents have taken the lives of more than four million Americans, many of them young people. Here again, government played a pivotal role in reducing the carnage. Traffic lights and speed limits helped. When studies in a new field, “injury science,” demonstrated that crashes were preventable, Nils Bohlin, an aeronautical engineer for Volvo in Sweden, designed a seatbelt to absorb injury to the chest and pelvis on impact. Although Volvo chose not to enforce the patent, American car companies resisted. They changed their ways after Ralph Nader (who, in essence, invented the role of consumer advocate) published Unsafe At Any Speed, and, in 1966, Congress enacted the National Traffic and Motor Vehicle Safety Act. Fatalities per 100,000 miles driven dropped precipitously.

Johnson leaves his readers with a lot to think about. He notes that Jefferson’s “catalogue of evils” has many pages left in it, like malaria, which 200 million people contract each year, and the climate crisis (which is caused by coal-powered plants, automobile emissions, deforestation, and the exponential increase in livestock production). Johnson wonders whether more public-private partnerships will emerge (with new approaches, for example, to immunotherapy and machine learning) to address them. In the wake of the pandemic, he asks, could a global NGO be formed, with a mandate to produce and distribute vaccines, fund and develop new variants.

Not surprisingly, Johnson speculates about the implications of raising the ceiling of life expectancy further and faster. Do we want radically expanded lifespans? Would we prefer “healthspans,” unimpaired by disease or injury, followed by quick and painful deaths? Or, with global temperatures rising and the population exploding (until 2050), are we worrying about the wrong problem?