Since modern man first appeared in the archaeological record, life expectancy (at birth) has slowly increased, from only the mid-20s for early man to today’s global average high of about 67. For those who survive past their mid-teens, however, life has always averaged nearly 40 years longer.

The oldest confirmed human – a French woman named Jeanne Louise Calment who died in 1997 at the age of 122 – marked what generally is thought to be the maximum human lifespan. However, recent research indicates there may be no absolute maximum lifespan, only a life expectancy limited by infant mortality, childhood deaths, disease, accidents, and war.

When Social Security was enacted in the United States in 1935, it set a benefits-eligible retirement age of 62, which was beyond the actuarial tables’ American life expectancy at the time. That has increased, for full benefits, to about 67 today, but U.S. life expectancy for those reaching retirement is more than 10 years beyond that age and the number of Americans living into their 80s, 90s, or even past 100 has increased dramatically.

While that – and especially the beginning retirement of the Baby Boom generation (born 1945-65) – is putting Social Security under extreme pressure, an aging population of military veterans – significantly expanded by a decade of war in Southwest Asia – will do the same for the Department of Veterans Affairs (VA). Even the Department of Defense (DoD) is being affected, with service members living longer, healthier lives not as eager to leave the military and the new TRICARE for Life program acting as a Medicare supplement for veterans 65 and older.

The current veteran population dates back to those born as early as the 1920s and grows larger with each succeeding generation. Even with better overall health, those numbers mean the VA will face a constantly increasing demand for health care, at least through most of this century. And in addition to the possibility of an older active duty, Reserve, and Guard population, more veterans also will mean increased TRICARE for Life expenditures for DoD.

War and military medicine – especially in the past decade – have played a significant role in increasing American life expectancy. Treatments for what in the past would have been fatal wounds, improved long-term care and rehabilitation, and advances in bio-technology, regenerative medicine, transplants, etc., for the military have provided equivalent life-saving care to the civilian population. And military medical research, which has become far more expansive and intensive in recent years, also has opened new doors and possibilities for non-military-specific research that could dramatically increase human health and life expectancy even more.

“That’s a good news story – there’s no question people are living longer and we hope both the DoD and VA health care systems will add to that,” said Dr. Jonathan Woodson, assistant secretary of Defense for Health Affairs and director of the TRICARE Management Activity. “And if we build healthier populations, we can care for these individuals longer and at lower cost.

“But for those wounded in war who are likely to survive longer and require services, I would like to state unequivocally we have a commitment and understanding to provide services for as long as they need them. That includes prosthetics, mental health care, etc. One of our strategies is to improve overall population health, making sure we bring the important focus to prevention measures to keep our people healthy as long as possible.”

Not everyone is as sanguine about the prospects of a population of centenarian – much less super-centenarian – veterans later in this century and beyond, as there is general agreement many young warfighters now in combat in Afghanistan almost certainly will still be on the VA health care rolls at and after the turn of the 22nd century.

The Census Bureau reported the number of centenarians in the United States more than tripled from 1980 to 2010. And according to the Department of Health & Human Services (HHS) report, “A Profile of Older Americans: 2010,” the United States will see a 36 percent increase in the over-65 population during this decade alone.

“By 2030, there will be about 72.1 million older persons, almost twice their number in 2008 [and more than 23 times as many as in 1900]. People 65-plus represented 12.9 percent of the population in the year 2009, but are expected to grow to be 19.3 percent of the population by 2030. The 85-plus population is projected to increase from 5.6 million in 2009 to … 6.6 million in 2020,” the report predicted. “In 2009, 41.6 percent of noninstitutionalized older persons assessed their heath as excellent or very good, compared to 64.5 percent for all persons aged 18 to 64 years.

“During the next three to four decades, we can expect a very dramatic increase both in the number of elderly persons and in the proportion of elderly persons in the population. The arrival of the large Baby Boom cohorts at age 65 will trigger the large increases in the number and percentage of elderly in the next half century. These prospective demographic changes have given rise to a general concern about the social, economic and physical ‘health’ of our nation’s population,” according to the report.

As the Baby Boom generation continues to age, it will push each succeeding age category to record highs – such as an estimated 88.5 million people age 65 and older by 2050. That includes a 400 percent increase in the over-85 population, boosting their part of the total population from about 1.4 percent today to 5 percent by midcentury. Aside from the sheer number of Baby Boomers, those changes will be heightened by shifts in birth rates, the volume and age pattern of future immigration, improved medical care – and lower birth rates in the generational groups born after 1965.

“The rapid growth of the elderly, particularly the oldest old, represents in part a triumph of the efforts to extend human life, but these age groups also require a disproportionately large share of special services and public support. There will be large increases by 2030 in the numbers requiring special services in housing, transportation, recreation, and education, as well as in health and nutrition,” the aging report continued.

“There will also be large increases in some very vulnerable groups, such as the oldest old living alone, older women, elderly racial minorities living alone and with no living children, and elderly unmarried persons with no living children and no siblings. These are also groups with high percentages living in poverty or with low incomes. The number of persons requiring formal care (mainly nursing home care) and informal care (mainly care at home) will rise sharply even if the share of persons at each age remains unchanged. Accordingly, there will be a large increase in the numbers participating in various entitlement programs, such as Social Security and Medicare.

And the VA.

Committees in both houses of Congress, as well as independent studies by DoD, VA, HHS, academia, and others, are trying to determine the best projections, not only for the number of increasingly older veterans, but also what it will cost to continue benefits. Those numbers also tend to change rapidly, as with the VA’s August 2010 extension of grant payments to Vietnam veterans for Parkinson’s Disease, certain types of leukemia, and heart disease – the nation’s leading cause of death – in addition to lung cancer, prostate cancer, and other major ailments. The initial cost projection for that change, based on disease rates in the general population, was $42.2 billion across 10 years, but a later recalculation, looking only at Vietnam veterans, raised that projection by 60 percent, to $67 billion.

“The irony [is] that the veterans who saved this country are now, in a way, not helping us to save the country in this fiscal mess,” Sen. Alan Simpson, R-Wyo., an Army veteran, former chairman of the Senate Veterans’ Affairs Committee and co-chair of the president’s deficit commission, said at the time. “It’s not that I’m an uncaring person, but common sense is the most uncommon thing in Washington.”

However, there are those who believe an aging population will cost the government less. In order to reach those high ages, they first must survive the most costly and health-destructive period in American life – the 50s, where obesity, lack of exercise, poor diet, etc., are the leading causes of poor health and death. Those who live beyond 70, especially with the ongoing and increasingly rapid evolution in medicine, thus are likely to be healthier, overall, than those in middle age.

A National Research Council study released in January 2011 confirmed better health care for middle-aged Americans will lead to longer lives. While that also would mean more funds to cover later-life pension and Social Security benefits, the study estimated it also would result in a major decrease in health care costs – nearly $18,000 per person. That converts to a health care savings of more than $1.1 trillion by 2050, more than half in government payments.

The nation’s oldest veteran and last surviving combatant from World War I – having lied about his age (16) to join the Army in 1917 – died in February 2011 at the age of 110. While there are few veterans even close to Frank Buckles in longevity, more and more are moving in that direction. An 18-year-old who went to war in 1942, for example, would now be almost 90, which is no longer a major anomaly.

VA costs also are likely to begin rising as more and more veterans become Internet literate and learn about programs they may not have known existed. One VA analysis reportedly discovered only 27 percent of veterans and 14 percent of surviving spouses with potential eligibility have applied for the Veterans Non-Service Connected Improved Pension Benefit Program. It is open to any veteran (including Coast Guard) with at least 90 days active duty, at least one of which was served during a U.S.-declared war, even if not as a combatant. The benefits help cover specific financial needs for those demonstrating a physical need for health care not already covered.

States, counties, and cities also are beginning to expand services to veterans, programs that also will be affected by a population increased by post-9/11 military expansion and living decades longer than their predecessors. New York State, for example, estimates at least 78 percent of its 1 million resident veterans are older than 55, with both total numbers and ages rapidly increasing.

Concerns about the impact of aging veterans on the VA health care system are not new, as evidenced by a 1983 National Institutes of Health (NIH) study entitled, “Aging Veterans: Will They Overwhelm the VA Medical Care System?” But it is more than just raw numbers and percentages or even increasing age.

With each increase in human life expectancy has come the appearance of ailments rarely – if ever – seen before, simply because few people lived long enough for those to appear or become life-threatening. Adult onset (Type II) diabetes and Alzheimer’s are two major examples, but others may develop in the future as the result of recently recognized combat-related problems, such as post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI), along with problems that may develop with increasing age for amputees or those who survived severe burns.

According to the VA National Center for PTSD, “many older veterans find they have PTSD symptoms even 50 or more years after their wartime experience.” As combat-related problems, both TBI and PTSD are as old as war itself, the latter previously having been known as “shell shock,” “battle fatigue,” “combat stress reaction,” etc. But only now, with the accumulation of clinical data leading to its redesignation as PTSD, are those afflicted living past age 75 in large numbers.

“Many older Veterans have functioned well since their military experience. Then later in life, they begin to think more or become more emotional about their wartime experience. As you age, it is normal to look back over your life and try to make sense of your experiences. For Veterans, this process can trigger Late-Onset Stress Symptomatology (LOSS),” according to the VA.

Similar age-related developments already have begun to emerge or are expected for those who survived a range of battlefield wounds that would have meant death – or significantly shorter post-combat lives – in earlier wars.

Another change in the veteran population – and one with significant questions as they grow older – is the number of women who have served in the military, especially in the current conflict. While comprising only about 1.8 million of the nation’s 23 million living veterans, women are one of the fastest growing segments of that population. The VA estimates female veterans will increase from 7.8 percent today to 10.5 percent by 2020. Given women in the United States continue to outlive men by five to 10 years (although that gap has been growing slowly smaller) and more women are joining the military, by 2050 they are expected to be a significant share of the veteran population – especially those 70 and older.

An aging population is more widespread than U.S. military veterans, of course. It extends to the entire U.S. population and globally, with the number of people age 65 and older worldwide expected to double by 2040 to 1.3 billion – 14 percent of the Earth’s forecast population at that time – according to a National Institute on Aging study. Medical advances developed for the U.S. military – and following on to the care of veterans – also will affect global health care, just as developments elsewhere will have application in the United States.

The big question for the VA – and all federal, state, and local governments – as the 21st century progresses will be cost: With a presumably unshakeable pledge to provide health care for all senior citizens – and a particular emphasis on veterans – but a U.S. and global economy currently facing severe problems, how can that rapidly growing population best be served?

As noted by former Census Bureau Director Louis Kincannon: “The social and economic implications of an aging population – and of the baby boom, in particular – are likely to be profound for both individuals and society.”

This article first appeared in The Year in Veterans Affairs & Military Medicine: 2011-2012 Edition.