Exactly where we will stand in the long war against disease by
the year 2050 is impossible to say. (111) But if developments in research
maintain their current pace, it seems likely that a combination of improved
attention to dietary and environmental factors, along with advances in gene
therapy and protein-targeted drags, will have virtually eliminated most major
classes of disease. From an economic standpoint, the best
news may be that these accomplishments could be accompanied by a drop in
health-care costs. (112) Costs may even fall as diseases are brought under
control using pinpointed, short term therapies now being developed. By 2050
there will be fewer hospitals, and surgical procedures will be largely
restricted to the treatment of accidents and other forms of trauma (外伤).
Spending on nonacute (慢性病的) care, both in nursing facilities and in homes, will
also fall sharply as more elderly people lead healthy lives until close to
death. One result of medicine’s success in controlling disease
will be a dramatic increase in life expectancy. (113) The extent of that
increase is a highly, speculative matter, but it is worth noting that medical
science has already helped to make the very old (currently defined as those over
85 years of age) the fastest growing segment of the population. Between 1960
and 1995, the U. S. population as a whole increased by about 45%, while the
segment over 85 years of age grew by almost 300%. (114) There has been a
similar explosion in the population of centenarians, with the result that
survival to the age of 100 is no longer the newsworthy feat that it was only a
few decades ago. U. S. Census Bureau projections already forecast dramatic
increase in the number of centenarians in the next 50 years: 4 million in 2050,
compared with 37, 000 in 1990. (115) Although Census Bureau
calculations project an increase in average life span of only eight years by the
year 2050, some experts believe that the human life span should not begin to
encounter any theoretical natural limits before 120 years. With continuing
advances in molecular medicine and a growing understanding of the aging process,
that limit could rise to 130 years or more.