 Many of us remember the book Daring to Live to 100 published in 1996 by gerontologist physician Dr. Walter Bortz of Palo Alto. Whenever I mentioned his book, the majority of my friends either scoffed or reacted in horror at the thought that they might live to such an enfeebled ancient age. But I was intrigued. At 58, I was a vegetarian and a daily walker and weekend hiker; I had taken some of the "99 steps to 100," as outlined in Bortz's book.
Bortz points out that life is a series of choices, but the critical point comes at midlife when a "go, no-go" decision is required. This is the doctor's "dare" to be 100. When "no" becomes easier than "yes," then life and its full expression are in jeopardy, and the elder begins to disengage from living. "It is no coincidence that 75 is the median age of death in America," Bortz says. "It is nature's confirmation that when meaning becomes lost, life is over."
In spite of the courage and determination needed to meet the dare, centenarians are increasing dramatically throughout the world. The 1990 census counted 37,306 centenarians in the United States; in the last 10 years that number has doubled, making centenarians the fastest-growing age group within the fastest-growing segment of our population: those 85 and older. It is predicted that by 2025 in the United States, we will have 400,000 centenarians.
The increases have attracted the attention of medical researchers. What contributes to a healthy long life? How long can the human life be extended? The oldest living person on record is Jeanne Calment, a French woman, who survived to 122 years of age. A study of supercentenarians (elders of 110 or more years), reported in June 2004 by L. Stephen Coles, suggests that although average life expectancy has increased in the last century, exceeding Calment's benchmark age set in 1997 will be difficult without some new unknown form of medical breakthrough.
Genetics contribute to long life, but it's only part of the story. A study of 424 centenarians (97119 years) was released in March 2003. It classified the subjects as Survivors, Delayers and Escapers. Key was the ability of the Survivors to overcome any of 10 major lethal illnesses (hypertension, heart disease, diabetes, stroke, nonskin cancer, skin cancer, osteoporosis, thyroid condition, Parkinson's disease, and chronic obstructive pulmonary disease) and one ocular disease (cataracts) that befall the elderly population.
Delayers were those who were able to stay healthy and delay the onset of age-associated illness until the age of 80 or thereafter. Escapers were those who attained 100 years of age with none of the age-associated illnesses. When the most lethal diseases of the elderly (heart disease, nonskin cancer, and stroke) were examined, higher percentages of centenarians delayed or escaped these dangerous diseases. Maintaining health is an important part of the story.
Theories of why we age include the notion that a biological clock determines one's life span. Studies with fruit flies, worms, rodents, and primates pay off with longer life spans that are sometimes doubled. Much remains to be done to apply this to humans. Studies of cell senescence 50 years ago sought to force the cells to continue to proliferate, but many experts today think that the natural death of cells protects us from cancer, whose cells are immortal and reproduce in an uncontrolled manner. Studies in worms and fruit flies have suggested the use of antioxidants to control free radicals and repair the damage to cell membranes, proteins and DNA. Again, more needs to be known about the effects in human systems.
We are learning more about what aging is from the centenarians who are healthy and happy. Most of them advise us to "eat the right food, exercise and remain mentally curious." When asked what they would wish for, many said they would like better eyesight, better hearing, to be more mobile and to remain cognizant. Many worried about losing their mental capacities and kept mentally stimulated by reading daily newspapers, playing bridge or Scrabble, working crossword puzzles and writing letters or memoirs. Recent studies have shown that being intellectually challenged can stimulate a growth of new nerve connections to replace the slow loss due to aging.
High levels of HDL cholesterol may have a role in protecting against cognitive decline. A study in March 2003 of 139 centenarians showed significantly higher than normal HDL cholesterol levels, a parameter that was strongly correlated with cognitive function.
Lynn Peters Adler, J.D., in her book Centenarians: The Bonus Years, profiles centenarian Dr. Michael Heidelberger, considered by many to be the father of immunochemistry. A photograph of the smiling doctor shows him in his laboratory at New York University Medical Center at age 100, still conducting research, writing and lecturing. Peters says, "Scientists and lay people alike are beginning to look upon these oldest of the old as beacons of a new, longer lived age—possibly, the Age of Centenarians."
Andrea Dorey is a licensed vocational nurse, medical writer and former AARP president. Contact her at andid@cagreens.org.
|
