Mortality

From a public health perspective, mortality is the measure of death in a population. The most general of these measurements is the crude mortality rate, which measures the number of deaths in a population over a specified period regardless of age or cause. Results of this measure are usually reported per a multiple of 10. In order to correct for population fluctuations, a midyear estimate of population size is usually used for this measure.

To better account for differences in populations, however, adjusted mortality rates are more commonly reported. Age-adjusted mortality rate, which takes into account the difference between two populations’ age distribution, is the more commonly reported figure if it is possible to obtain.

Cause-specific mortality, gender-specific mortality, and age-specific mortality are other common measures that as the names imply, measure the number of deaths that occur within a specific category. For most of human history and across all continents, life expectancy beyond the age of 40 was not very promising. If individuals survived a childhood where they were exposed to infectious diseases, possible food shortages, and incurable congenital birth defects, these same individuals would enter an adulthood filled with an equal amount of adversity. Pregnancy, war, pestilence, and lethal dangers in occupations posed constant risks to an individual's survival.

Main causes of mortality now differ across the globe. Although many different interventions have played a role in altering human mortality, such as advances in pharmacotherapeutic and surgical treatments, two public health interventions—vaccines and sanitation practices—have provided some of the greatest impact on this change. In countries with more developed economies and established social, health, and sanitation infrastructure, infectious diseases have lost the impact on mortality which persists in countries and regions where there is less sanitation and overall economic development.

In 1900, the number of deaths attributed to infectious diseases was nearly equal to those attributed to noninfectious causes. Except for the sharp peak during the influenza pandemic of 1918, the first half of the century witnessed a steep decline in the rate of death due to infectious diseases, which coincided with the initiation of wide-spread vaccination and sanitation programs. After 1950, the crude all-cause mortality line and noninfectious disease mortality line nearly overlap, demonstrating that in the latter half of the 20th century, the majority of deaths were due to noninfectious causes and inversely, only a small fraction of the deaths could be attributed to infectious diseases. Such an observation is an example of the success of these two public health initiatives in eliminating the risk of death due to infectious diseases and a possible framework to be used in regions where death due to infectious diseases still persists.