March 29, 2006

Adding Life to Years

The latest statistics on life expectancy were released by the National Center for Health Statistics in January, 2006 and they show continued improvement in the prospects for old age (DL Hoyert, M. Heron, SL Murphy, and HJ Kung, “Deaths: Final Data for 2003,” National Vital Statistics Reports. National Center for Health Statistics, Hyattsville, MD, released January 19, 2006). Life-expectancy at birth is 77.5 years, as of 2003, the year on which the results are based, surpassing the previous record, from 2002, by 0.2 years. The age-adjusted death rate (that is, the death rate taking into consideration the distribution of ages in the population) is also at a record low, down 1.5% from 2002.

If we examine the statistics more closely, we discover several interesting observations. First, let’s look at life expectancy at age 65. Life-expectancy at birth reflects the risk of dying of congenital abnormalities or of the dangers that affect young adults, such as AIDS and homicide. For older people, what is of concern is how much time they are likely to have left if they have made it through middle age. The answer is that life-expectancy at age 65 is an impressive 18.4 years. It is even higher for white women (19.8 years) and a little lower for white men (16.9 years). What is disturbing, however, is how much lower life-expectancy at age 65 is for black men (14.9 years). Black women, by contrast, are just about exactly at the national average (18.5 years).

Since age 65 really is not considered “old” any more, what is of even greater interest is the data on life-expectancy at age 75. The 2003 data indicate that 75-year olds can expect, on average, to live for another 11.8 years. Again, the situation is a little better for white women (12.6 years) and a little worse for white men (10.5 years). And again, the life-expectancy for black men is unfortunately only 9.7 years, although black women are almost as well off as white women, in terms of years of life left (12.4 years compared to 12.6 years).

Another important result reported by the government is that while the age-adjusted death rate is down for several of the leading causes of death, including heart disease, cancer, and stroke, the rate of Alzheimer’s disease continues to rise. Regrettably, this means that as we make strides in the treatment of many of the diseases afflicting the elderly, the net result is often that people live long enough to develop and ultimately die of dementia.

What is not discussed in the government statistics is the rate of chronic disability in old age. While we all aspire to live longer, for many of us it is critical that those additional years be good ones. We want to live longer but we want to be as independent as possible. We don’t want to require the help of others for our most basic activities—dressing, bathing, eating, walking. It turns out that the studies that have been done analyzing disability rates show that from 1982 to 1999 (no more recent figures are available for the U.S.) disability declined: one report calculates that the decline from 1982 to 1989 was 0.26% per year, the decline from 1989 to 1994 was 0.38% per year, and the decline from 1994 to 1999 was 0.56% per year (Kenneth Manton and XiLiang Gu, “Changes in the Prevalence of Chronic Disability in the United States Black and Nonblack Population Above Age 65 from 1982 to 1999,” Proceedings of the National Academy of Science (2001); 98: 6354-6359). A second report, summarizing the results of various other studies, suggests that the rate of decline in disability among the elderly has been 1% per year for several decades (David Cutler, “Declining Disability Among the Elderly,” Health Affairs (2001); 20: 11-27).

But if we examine the data on chronic disability carefully, what we find is that the improvements are most pronounced for domains such as the ability to cook or shop or clean house. The fraction of the elderly population with severe disability remains virtually unchanged. Moreover, historical research indicates that it is hazardous to predict future rates of decline based on recent trends: in the past, sharp declines in disability rates have often been followed by stability or increases in disability. (See: Donald Redfoot and Sheel Pandya, “Before the Boom: Trends in Long-Term Supportive Services for Older Americans with Disabilities,” AARP Policy Institute, October, 2002.) Recent work on the potential long term outcome of the obesity epidemic, for example, predicts that even the gains in life expectancy may be reversed (see S. Jay Olshansky, Douglas Passaro, Ronald Hershow et al, “A Potential Decline in Life Expectancy in the United states in the 21st Century,” New England Journal of Medicine; 2005; 352: 1188-95).

What should we conclude from all of this? We can conclude that most of us who reach retirement age will live past 80. During much of our old age, we will be quite vigorous. But we are still at considerable risk for developing frailty (severe physical disability) and dementia (cognitive disability). Preventing these conditions, treating these conditions, and developing supportive care that will enable us to make the most of our old age despite these conditions, are the challenges that lie ahead.

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