Have you heard the expression, “If Mother Nature doesn’t get you, Father Time will?” For the first time in the history of mankind, people in developed countries can expect to live long enough to become old. Census bureau statistics show that the average lifespan across the world was 30 or less in 1900, 46 by 1950, and was 66 by the late 1990s. Our medical, social and economic progress in the 20th century alone has tacked 25–30 years onto our life expectancies. Let’s consider some of the implications of this trend in this week’s Insight.
In the United States, at the beginning of the 20th century, the average life span was 47 and now it’s about 76. The reason for the longer lifespan is not slower aging. Rather, because of improved sanitation, we’re avoiding a variety of once-prevalent communicable diseases. We’ve decreased death during childbirth, and developed immunizations to prevent a variety of illnesses that formerly generated significant morbidity and mortality.
The leading causes of death in the U.S in 1900 were (in order of prevalence) pneumonia, tuberculosis, diarrhea and intestinal illnesses, heart disease, stroke and brain lesions, kidney inflammation, and accidents. In 1997, the top seven were heart disease, cancer, stroke and brain lesions, lung disease, accidents, pneumonia and flu, and diabetes. You can see how the spectrum has shifted away from infections as leading causes. These days, genetic predispositions, unhealthy lifestyles, and exposure to a variety of environmental toxins are the big actors on the ‘death list.’ And, with the major medical advances in control of heart disease, hypertension, and diabetes, we are seeing a decline in the mortality rates from these health problems as well.
Too, mapping of the human genome progresses rapidly. In essence, the genome is “the instruction book for human biology.” As we progress in our understanding, we will be able to alter both genetic predispositions for certain diseases, and genetic consequences of certain illnesses. . .including cancer. Even the cellular changes created by the ‘normal aging process’ can be manipulated with such knowledge. Getting into your genes will take on a host of important medical, legal, and ethical considerations; and clearly, people will be living longer as a result.
Through improvements in health and sanitation, the median lifespan (that is the 50% survival rate to a given age) has increased dramatically. However, the maximum lifespan seems to be increasing as well. Since approximately 1950, the number of centenarians (those aged 100 and over) has doubled every 11-12 years. Jeanne Calment, a celebrated French woman, died last July at the age of 122 and holds the current record for the maximum verifiable human lifespan. For most of us middle-aged folks living relatively health-conscious lives, the best we can realistically expect is 110. Men have a 5–7 year decreased life expectancy from birth than women. Interestingly, however, the mortality graphs of males and females are parallel. What this means is that although men ‘age’ faster than women, the rate of aging in men and women is the same; the difference is that men have their ‘onset of aging’ at an earlier age than women do and die sooner as a result. Our hormonal differences presumably explain this phenomenon, although many women may say it’s simply due to meanness!
Approximately 35 million Americans today, or 1 in 8, are age 65 or older. . .with persons 100 years of age and older being the fastest growing segment in our population. By the year 2030, one in five Americans will be 65 and older, and the actual number individuals in this category will rise to 65 million. Among the ranks of these older Americans will be the Baby Boomers; during the next 12 years, 76 million of us will enter the Graying Geezer ranks of 65 plus! And, the Census Bureau predicts that one of every nine baby boomers will survive to at least age 90.
As a result of these realities, we must continue to develop programs and policies designed for a longer living community of older citizens. Practical considerations of consumer protection, economic security, health care delivery, and long term care and caregiving are just a few of the current and emergent issues to address. And, on personal levels, we need to remember that QUALITY of aging is primarily determined on an individual basis. The factors shown to be the major predictors of high functioning in old age are: 1) Education 2) Exercise, and 3) A Sense of Efficacy. The latter factor addresses one’s sense of control or influence on daily activities–one’s sense of accomplishment and self-worth. As Sam Harris so poetically expresses it in song, “Don’t Let the World Step on Your Soul.” I suspect that none of us wishes to live longer simply for the sake of racking up more years ‘above ground’. Rather, let us strive for quality first through good health habits and self-care. Nurturing ourselves and the other important individuals in our lives will always enrich whatever time we have upon this earth. And, that, my friends, is about the long and short of it.
Stephen L. Hines, M.D.