Historical keywords: Mortality

The Journal : Current Issue
Anne Hardy (a.hardy@ucl.ac.uk)

Mortality is derived from the Latin mortalitas, which comes from mortalis, subject to death, mortal, originally from mors, death. Alongside its use in such compounds as mortality rates, mortality is used to describe: the condition of being mortal; the death of an individual; death on a large scale; and the number of deaths in a given area, period, or from a particular disease.

The London Bills of Mortality were the first death statistics ever collected and were introduced in the early 16th century to predict outbreaks of bubonic plague. The recording of cause of death began in 1629. But by the 1820s such records were unreliable and so were abandoned with the creation of the General Register Office for England and Wales in 1837. The study of mortality now came into its own. William Farr (1807- 83), pioneer analyst of the new statistics, revealed the differences in mortality between, for example, town and country, and between north and south. Such statistics were vital to proponents of public health whose analysis of death and disease enabled them to pressure politicians and civic authorities to implement reform.

One result of the new registration system was that the modern scientific meaning of mortality became established: "The ratio of the total number of deaths in a year in a given population from a particular cause, group of causes, or all causes, to the total population" (WHO). Mortality rates can be subdivided into various categories. The crude mortality rate (number of deaths per 1000 population in a given year) is a clumsy descriptive tool and so death rates are commonly standardised for age and sex to reflect the relation between death and the structure of the population more accurately. Among age-specific rates, the infant mortality rate (deaths of babies aged under 1 year per 1000 livebirths) is of especial importance. Introduced in the late 19th century, it was soon recognised to be a sensitive indicator of social and environmental conditions, and has remained one of the key indices of the health status of whole populations. In the 20th century, standardised mortality rates became a major tool of demography and epidemiology. As death is a main determinant of population size, mortality rates have come to play a central part in debates over public health, population increase, and demographic transition. Thus, the word mortality now has complex layers of association so that the precise sense in which it is being used has always to be defined.