Mortality Decline in Europe.
What were the main characteristics of declines in mortality in the
19th and early 20th centuries? How might they be explained?

by

Christine Langhoff

The decline in European mortality which began in the seventeenth century and accelerated in the eighteenth and nineteenth centuries has two main characteristics: the decline in the crude rate of mortality (the relation between numbers of deaths and the average population in a given year) and a later decline in the rate of infant mortality (the relation between the number of infant deaths under 12 months and the number of registered live births in a given year). Many different explanations for these declines have been given. I am going to consider the McKeown thesis which concluded that improving nutrition is the best explanation for the historical fall in mortality in Britain, as well as the theory that increasing inherited resistance to infectious diseases was the major factor.

Professor Thomas McKeown’s “The modern rise of population” was published in 1976 as an accessible summary of over two decades of painstaking empirical work, applying the insights of current medical and epidemiological knowledge to a historical analysis of Britain’s detailed national series of death records. McKewon simply and conclusively showed that many of the most important diseases involved had already all but disappeared in England and Wales before the earliest date at which the relevant scientific medical innovations occurred and he concluded that improving nutrition is still the best explanation we have for the historical fall in mortality in Britain. This ambitious general explanation was based on a number of purely speculative premises regarding the characteristics of the pre-industrial demographic regime. These have since been radically undermined as a result of the revolutionary empirical findings that have emerged from more recent work of demographic historians. It has been found that the notion which underpinned McKeown’s grand thesis, that there had been a single movement of continuous and uninterrupted mortality decline across the last three centuries, can no longer be considered valid because the relatively low level of mortality attained by the 1820s after a century of improvement was the same as that previously experienced in the late 16th century. Thereafter, overall mortality ceased to fall for almost half a century throughout the central decades of the mid-nineteenth century.

The analysis of death-rates in 19th and 20th century Britain which was presented by McKeown is based on a uniquely detailed historical source material. Tehse are the returns of deaths classified by age and certified cause of death which are available for the entire population of Britain, excluding Scotland, from July 1837 onwards. Details about the numbers dying from each disease by age and sex was combined with comparable information regarding total population alive at each of the national censuses taken every ten years to produce age-specific death rates. McKeown grouped the individual diseases into four broad etiological categories, according to what modern medical science understands to be the main pathways of transmission involved in the spread of each particular disease: the airborne category of diseases, the water- and food-borne category, other diseases also attributable to micro-organisms and the category of afflictions which are not microbiotically caused. With this simple but very useful classification system established, he wet on to argue that any observed fall in the incidence of a disease must be due to one of the following five causes:

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