Wednesday 2 November 2016

GROWING OLD

What is growing old, anyhow? A half century ago, people thought that the most obvious aspects of growing old—senility, strokes, heart disease, and cancers—were part of the natural process of aging. Now we recognize that they may often be wreckage from our collisions with the microbial world. If most microbes deal with us benignly, then we are compelled to ask how much of the less obvious part of aging is caused by microbial fender benders. Logic tells us that it may be much. If so, what can we expect from human life simply by preventing the damage from our encounters with microbes?

The diversity of activity among the elderly gives us a clue. The bodies of some 50-year-olds are falling apart, whereas some people pushing 80 seem to be cavorting like teenagers. I know this from personal experience because my mother, Sara Jeanne Ewald, is one of these teenagers in her late 70s. She does not respond in ways typical of a person of this age group. For instance, she was run over by a truck in November 1998 and brought to the hospital with a badly fractured pelvis, a broken set of ribs, and a punctured lung. She left the hospital in December and was walking with a cane in January. In April she discarded the cane and departed on a European tour with her boyfriend, leaving in her wake doctors and nurses who were happily scratching their heads in disbelief.

Could the recovery rate from such injuries depend on whether someone was lucky enough to be resistant to chronic infections? I don’t know. Many of the elderly and some middle-aged people have problems with osteoporosis; if infections play a role in this condition, then an elderly person who is resistant to such infections might be especially well able to heal broken bones. Sara Jeanne has been incredibly resistant to acute infectious diseases throughout her eight decades of life. “I must have a strong immune system,” she would often say to me as I was growing up. Perhaps that may help explain why she is zipping around like a college student on spring break instead of being hobbled by the ailments of old age.

Of course this account is just an anecdote. But what is an anecdote? In an effort to be scientifically rigorous, twentieth-century medical science has made anecdote a dirty word. Ardent attempts to codify rigor have stripped us of the benefits anecdotes provide. Anecdotal observations are essential for rigorous science because they provide possible clues to the solution of medical puzzles. Their true value often cannot be discerned without follow-up studies. They may turn out to be junk or gems. When anecdotal observations are followed up with careful studies, some will be recognized as spurious coincidences, whereas others will be recognized as the signposts that guided research to new breakthroughs.

The vision of medicine is sometimes blinded by the average. Any large cohort of 80-year-olds will include some who are youthfully active and others who have become immobilized by the “process of aging.” We see the same in 70-year-olds and 60-year-olds. But as the cohort becomes younger, our sense of what is normal changes. We begin to see the debilitation as something out of the ordinary and therefore deserving of a special explanation. We therefore begin thinking of the debilitation as disease rather than as part of the normal process of aging. Once this transition in thinking occurs, we are spurred to understand the cause of the illness. Perhaps when we understand the full scope of infectious causation and effectively prevent its damaging outcomes, vibrant 80-year-olds will be the rule rather than the exception.

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