The future of life expectancy

The members of the population who could potentially become aged 80 and older in 2050 are those
aged 40+ who are alive today. The actual numbers who will be age 80 and older in 2050 will therefore
depend almost solely on adult and old age mortality rates over the next 40 years. The history of the
decline of mortality and increase in life expectancy suggests that improvements in the standard of living
including increased and improved education and improved nutrition coupled with improvements in

public health stemming from an understanding of the germ theory of disease initially led to the
improvements, with medical achievements such as antibiotics and improved understanding of risk
factors for cardiovascular and circulatory diseases becoming factors only in the post–World War IIperiod with the largest strides for cardiovascular disease coming only in more recent decades. The
improvements in educational attainment of succeeding generations have been credited in large part for
improvements in child mortality during the past century, since educated mothers are especially likely to
understand and take advantage of measures to reduce infection. The effects of continuing progress will
likely be seen in coming decades as well, since educational attainment is associated with improved
health and survival at older ages. Countries vary in the extent to which the "future elderly" cohorts will
be more educated. China in particular will have a much more educated elderly population in 2050 (with
more than two-thirds of the 65+ population having completed secondary school) than it did in 2000
(when only 10% of older people had a secondary education). In the United States and other rich
nations, this change has largely taken place already; future changes in educational attainment of the
elderly population will be less dramatic.
Holding aside the possibility of new infectious diseases ravaging populations as AIDS did in some
African countries, debates about future life expectancy revolve around the balance and influence of risk
factors such as obesity, the possibility of reducing the deaths from current killers such as cancer, heart
disease, and diabetes, whether there is some natural limit to life expectancy, and the distant though
nonzero possibility that science will find a way to slow the basic processes of aging.
While some have posited natural limits to human life expectancy, the limits have been surpassed with
some regularity and at the very oldest ages in the leading countries with the highest life expectancy,
there appears to be little evidence of any approaching asymptote. Indeed a surprising discovery was
that life expectancy in the leading country over the last century and a half, with different countries
taking the lead in different epochs, could be represented almost perfectly by a straight line, with the
increase for females showing a steady and astonishing increase of three months per year or 2.5 years
per decade (Fig. 70-3). No single country kept that pace of improvement the entire time, but this trend
does call into question the notion that improvement must slow down, at least in the near future.