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Environment
and Disease
Environment and
Life Expectancy
  There has been a great increase in life expectancy
since 1900. Our life spans today extend well into the 70s. Many
things have happened since 1900 to cause this very dramatic
increase in life expectancy. First is an increased standard
of living. We eat better, we are better housed, and we are warmer.
Second, there is better basic sanitation. We have sewers that
work and daily trash removal. Perhaps the biggest single change
is clean water. Death rates in various large metropolitan cities
decreased dramatically when clean water was brought into those
cities from a central source. Clean water is one of the major
elements of the healthier environment we have today.
Finally, we are able to control many acute infectious diseases
that primarily affect young people. In fact, most of the increased
life expectancy is a result of prevention of deaths in children
and young adults.   Children no longer die of infant diarrhea
and a variety of other diseases that exacted a great toll in
the past.
Now we live in a
predominantly middle-aged society that rapidly is becoming a
society primarily composed of older people. An individual's
life expectancy after the age of 50 has remained fairly constant
since 1900. However, the pattern of deaths has changed. We are
dying of different things. Death rates for such pulmonary diseases
as tuberculosis and pneumonia have decreased. Deaths from cardiovascular
disease have increased in the past, but appear to be leveling
off or decreasing. Yet cancer death rates have risen steadily
and still seem to be increasing.
As a result of these
different patterns of life and death we have to contend with
different diseases today. Now we are dealing unsuccessfully
with such chronic longterm diseases as cancer, heart disease,
kidney disease, and neurological diseases. We do not understand
the causes of these diseases; there appear to be many factors
involved. One of the prominent factors in the causation of many
of these diseases may be chemicals.
Pulmonary
Disease
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Heart
Disease
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Cancer
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On to Chemicals and Human Disease
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National
Institute of Environmental Health Sciences
National
Institutes of Health.
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