The Development of Vital and Medical Statistics, and Public Health, 1800-1860

Public health risk assessment grew into a formal discipline from two basic types of data collection: national censuses and regional vital statistics. Like many societies through history, western governments, including that of the United States, were doing census counts at regular intervals by the early 1800s. Such enumerations of population provided essential knowledge about, e.g., the size of national workforces, the number of men that might be called to military service, and the number that might be taxed to provide government services. Census data would eventually include detailed information about citizens’ age, family size, occupation, income, and much more. Initially, it was a tool to track longer changes in population size (where did it increase or decline, and by how much, for example.) Vital statistics data--records of births, marriages, and deaths--were usually kept at the local level, by clergy, and noted as they occurred. From the 1500s, in times of epidemic diseases such as plague, parish records supplied the data for the Bills of Mortality published to keep citizens apprised of the increased death rates. Parish records were often incomplete because they did not necessarily include local residents who didn’t belong to a local church.

The growth of nation-states, expansion of trade, and growth of industry in the early 1800s brought both an increase in population and major changes to its distribution, from rural areas to urban ones. Larger concentrations of people--many of them poor--in urban areas amplified problems connected to crowding and poor sanitation, especially disease transmission. Early public health reform was closely connected to social reform movements of this period, because many believed poverty, squalor, and disease stemmed mainly from deficient moral character. (Reformers also criticized brutal conditions in mines and factories because they created morally corrupting environments.) Lack of health care facilities meant that poor people who became sick and/or disabled, if they had no family to help them, often were committed to poorhouses or prisons, where they usually died. Social reformers hoped that more humane approaches to these unfortunate people might salvage them.

The health of the poor emerged as a social issue in the early 1800s, but public health was likewise very much an economic and political issue. Epidemics and widespread chronic illness both posed serious risks to communities. The growth of large, crowded cities, factories, prisons, and military camps provided excellent conditions for the spread of infectious diseases. Throughout the 1800s, growing cities and towns struggled with epidemics of cholera, typhoid fever, dysentery, measles, plague, smallpox, diphtheria, malaria, and yellow fever, along with endemic diseases such as tuberculosis. These affected people of all classes; outbreaks threatened economic productivity and military effectiveness, interfered with commerce when ports were quarantined, and increased the numbers on the poor relief rolls. Some epidemics, especially cholera, which first appeared in the west in the 1830s, provoked public panics and even riots. The usual strategies, such as quarantine, proved inadequate, and political leaders and physicians were desperate for solutions.

Medical explanations for disease did not yet include microorganisms such as bacteria and viruses (later known as the germ theory of disease). Though some bacteria could be seen with microscopes, their presence in diseased tissues seemed incidental; most physicians considered them irrelevant, or perhaps as products, not causes, of the disease. Likewise, there was no recognition that diseases such as typhus, malaria, and yellow fever might be transmitted by insect vectors, or that common flies might carry typhoid on their feet.

Physicians recognized some diseases, such as smallpox and syphilis, as contagious (that is, directly transferable from person to person). Most other sickness, they believed, resulted from the interaction between a patient’s own constitution, the immediate environment (including climate) and a particular causative agent, often called an "infectious poison." There was debate about whether the triggering poison was chemical or biological, how it was transmitted, and whether foul smells actually contained the poison or just indicated places where it might be present.

Searching for better ways to understand and remedy the growing problems of disease and poverty, statisticians and reformers (for example William Farr and Edwin Chadwick in Britain, and John Griscom and Lemuel Shattuck in the United States) investigated patterns of both poverty and disease incidence. They were surprised to find that disease and mortality correlated strongly with living environments in poor areas, where filth, inadequate diet, and poor drainage, waste disposal and ventilation were common. Sanitary reformers subsequently demonstrated that simply cleaning up filth in the streets and inside dwellings, and preventing outhouse and cesspool contents from contaminating drinking water could make a measurable difference. By the 1850s, they had also added new chemical disinfectants such as carbolic acid (phenol) and bromine to their toolkits.