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?

The analysis of death-rates in 19 ^th and 20 ^th 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: (i) an autonomous decline in the virulence of the micro-organism itself (ii) an improvement in the overall environment so as to reduce the chances of initial exposure to potentially harmful organisms. This could be either: (a) as a result of scientific advances in immunisation techniques (b) through a public health policy designed to sanitise the urban environment (iii) an improvement in the human victims’ defensive resources after initial exposure to hostile organisms. This could occur either: (a) through the development of effective scientific methods of treating symptoms

(b) via an increase in the level and quality of the exposed population’s

average nutrition intake, that is better and more abundant food, thereby improving the individual’s own natural defences.

McKeown examined the significance of these five possible causes of the mortality decline and concluded that the most significant factor must have been nutritional improvements.

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The problem with this conclusion is that it emerged merely by default, as a result of the sceptical devaluation of other factors including medical intervention, rather than because of any convincing positive evidence in its favour. When McKeown’s epidemiological evidence was reinterpreted it was found that it was no longer the decline of the airborne diseases as a unitary category which he had stated to be the predominant and leading characteristic of changing mortality patterns in 19 ^th century England and Wales, but rather the behaviour of the classic sanitation and hygiene diseases (e.g. diarrhoea, gastro-enteritis, typhus). There can be little doubt that the first two-thirds of the 19 ^th century witnessed an increasing incidence of such diseases, which was directly attributable to the unplanned proliferation of overcrowded cities and towns lacking even the most basic sanitary facilities such as proper water supply and waste disposal systems. Conversely, the ensuing disappearance of water-borne diseases in the last third of the century was due to the eventual provision of adequate sanitary facilities, long delayed but finally implemented.

Between 1801 and 1871 the rate of urban growth in Britain was quite unprecedented, both in the provinces and the metropolis. At the commencement of the 19 ^th century no provincial town contained as many as 100,000 inhabitants. By 1871 there were 17 cities over this size on mainland Britain, apart from London. Glasgow and Liverpool each numbered around half a million, whilst the capital had tripled to over three million. The stationary national figure of life at birth (approximately 40 years) across the second and third quarters of the nineteenth century merely summarises the nation’s average mortality experience, urban and rural populations together. This quite certainly belies wide geographical divergences in experience. Those remaining in the countryside were very probably continuing to experience the trajectory of slow but steady improvement which had characterised the second half of the 18 ^th century. By contrast those who migrated to the expanding cities and towns to bring up their families must have experienced a real fall in life expectancy on so doing. Whilst increasingly huge populations continued to concentrate ever more intensively in townships growing into cities but lacking the appropriate social overhead capital to preserve - let alone promote - health, then morbidity and mortality risks inevitably proliferated. Equally inevitably, these multiplying and compounding health hazards could only be alleviated through the appropriate social and political responses: the

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