Life Expectancy

Life expectancy is a term employed to statistically describe the average length of time a person within a given human population, such as a particular country or time period, lives from birth until death. Like other tools for determining the nature of demography, the measuring of life expectancy rates is sensitive to various factors. As a consequence, it can be calculated in different ways. For example, life expectancy may be measured without utilizing the infant mortality rate—this form of calculating life expectancy is commonly employed within nations that suffer from high child mortality levels.

Average life spans are longer today than in the past, thanks to modern technology and scientific understanding of disease. Increased wealth and improvements in standards of living have also led to better diets, making humans healthier and less [Page 1050]susceptible to particular diseases than in prior times in many parts of the world.

In some African nations, such as Swaziland and Botswana, citizens live on average for less than 34 years; in wealthy societies like Hong Kong and Andorra, people commonly live more than 81 years.

The introduction of technologies has been important in augmenting average life expectancies. Sir Joseph Bazalgette first developed urban sewage systems on a citywide scale in London during the Victorian age (in the mid-1800s). In addition, medical advances have played an important role in lessening the presence and influence of disease. Progressive medical thinking has helped make once life-threatening illness curable. Also in Victorian London, medical practitioners like Dr. John Snow were pivotal in understanding the true nature of disease. Dr. Snow, with his studies on cholera, was able to scientifically prove that cholera was a waterborne illness. Consequently, not only was the nature of disease better understood, but public administrations were better prepared to deal with incidents of illness. Over time this allowed levels of disease to decline and life expectancies to rise.

A variety of factors can influence life expectancy levels. Dietary patterns, in particular poor nutrition, greatly influence the level of life expectation. In places where diets are nutritionally poor, possibly as a result of famine or natural disasters like floods and typhoons that can devastate local harvests, occurrences of disease increase and life expectancy levels fall.

Of similar significance is the character of a society's urban places that may have rapidly grown to unprecedented levels in terms of spatial size, demographic scale, and urban density after the onset of industrialization. Extraordinary pressure may be put on the local infrastructure, which can result in environmental degradation such as water pollution and higher rates of disease, deprivation, and death. Under such conditions, epidemics may push up the mortality rates among those most susceptible to disease, such as old people, children, and disadvantaged social groups, thereby lowering life expectancy rates within the urban locale and the nation as a whole.

Generally, as the world has developed economically, life expectancy has increased. However, when a nation initially industrializes and experiences rapid urbanization for the first time, the poorest in society, especially in urban settlements, experience difficulties on an unprecedented level. Furthermore, as the number of poor within a nation may be great, this can negatively influence the life expectancy rate within the country. Immediately following industrial progress the country may experience a decline in average life span, even while national levels of wealth increase. On the other hand, as time passes following the onset of industrialization, life expectancy levels increase dramatically, especially when compared over a time frame of 100 years or more.

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