What Factors Affect Death Rates?
The rapid growth of the world's population over the past 100 years is not the result of a rise in the crude birth rate.
Instead, it has been caused largely by a decline in crude death rates, especially in developing countries.
Changes in crude birth and crude death rates for developed and developing countries, 1775-2002.
More people started living longer (and fewer infants died) because of:
increased food supplies and distribution
improvements in medical and public health technology (such as immunizations and antibiotics)
improved sanitation and personal hygiene
safer water supplies (which has curtailed the spread of many infectious diseases)
Two useful indicators of overall health of people in a country or region are:
life expectancy - the average number of years a newborn infant can expect to live
infant mortality rate - the number of babies out of 1000 born who die before their first birthday
Some good news is that global life expectancy at birth:
increased from 48 years to 67 years (76 years in developed countries and 65 years in developing countries) between 1955 and 2002.
is expected to reach 73 by 2025.
Between 1900 and 2002, life expectancy in the US increased from 47 to 77 years and is projected to reach 81 years by 2025.
Some bad news is that in the world's 49 poorest countries, mainly in Africa, life expectancy is 55 years or less.
In many African countries life expectancy is expected to fall further because of increased deaths from AIDS.
Distribution of the 40 million people infected with HIV in 2001. Numbers in parentheses give the number of deaths from AIDS in 2001.
Because it reflects the general level of nutrition and health care, infant mortality probably the single most important measure of a society's quality of life.
A high infant mortality rate usually indicates:
insufficient nutrition (under nutrition)
poor nutrition (malnutrition)
a high incidence of infectious disease (usually from contaminated drinking water)
World infant mortality rates in 2002.
Between 1965 and 2002, the world infant mortality rate dropped from:
20 per 1000 live births to 7 in developed countries.
118 to 60 in developing countries.
This is an impressive achievement, but it still means that at least 8 million infants (most in developing countries) die of preventable causes during their first year of life.
Between 1900 and 2002, the US infant mortality rate declined from 165 to 6.8.
This sharp decline was a major factor in the marked increase in US average life expectancy during this period.
Despite this improvement, 37 countries had lower infant mortality rates than the US in 2002.
Three factors keeping the infant mortality rate higher than it could be:
inadequate health care for poor women during pregnancy and for their babies after birth
drug addiction among pregnant women
the high birth rate among teenagers
The good news is that the US birth rate among girls ages 15-19 in 2002 was lower than at any other time since 1940.
Some bad news is that the US has the highest teenage pregnancy rate of any industrialized country.
Each year about 872,000 teenage girls become pregnant in the US (78% of them unplanned) and about 253,000 of them have abortions.
Babies born to teenagers are more likely to have low birth weights, the most important factor in infant deaths.