North America

The indigenous peoples of North America suffered as catastrophic a population decline as did those in what became Latin America. As already suggested, the North American Indians did not live in the same sort of extensive agricultural societies as existed to the south, nor did the new settlers come from a society like those of the Iberian Peninsula.

Endemic diseases such as dysentery and malaria, and epidemic diseases such as measles, smallpox, and yellow fever, were prevalent throughout the colo­nial period, but their severity seems to have differed substantially from North to South. Life expectancy was lower in Maryland than in New England in the seventeenth century, for example, and crude mortal­ity rates were higher and epidemic diseases more severe in the South than the North throughout the eighteenth and nineteenth centuries.

In the eighteenth century, crude death rates in New England ranged from 6 to 20 per 1,000 popula­tion, depending on the location of a given commu­nity as well as its age structure (Meindl and Swedlund 1977; Dobson 1987). In French Canada during the eighteenth century, the crude mortality rate varied from 23 to 39 per 1,000, again probably depending on the changing age structure of the popu­lation (Henripen 1954).

In the early nineteenth century, crude mortality rates varied widely as well. In northern U.S. cities they tended to be in the range of 18 to 25 per 1,000, increasing as one moved south to 80 or 90 per 1,000 in such cities as Savannah and New Orleans (Dob­son 1987). Though there is some disagreement, evi­dence now exists that mortality rates increased in the course of the first half of the nineteenth century (Meindl and Swedlund 1977; Kunitz 1984; Fogel 1986).

Though mortality crises seem not to have been frequent in New England during the colonial period, regular epidemics of measles and smallpox did sweep the population. They seem to have diminished by the end of the period as both diseases increasingly afflicted children, a sign that the population was becoming sufficiently large to convert the diseases into endemic diseases (Kunitz 1984). In general, how­ever, the curve of mortality from year to year re­tained the jagged, saw-toothed shape characteristic of the presence of epidemics (Omran 1975), although these were never of sufficient magnitude or fre­quency to keep populations from growing.

Mortality began to decline after the Civil War, though whether this occurred in the 1870s or 1880s is still a matter of disagreement (Kunitz 1984). Rob­ert Higgs (1973) has estimated that the crude mortal­ity rate declined from between 23 and 29 per 1,000 in the 1870s to 15 to 17 per 1,000 in the 1910s in urban areas; and from 21 to 23 per 1,000 to 14 to 15 per 1,000 in rural areas over the same period. These rates are roughly comparable to those observed among Catholics in Canada in the 1860s: 20.9 per 1,000 (Kalbach and McVey 1971). Among the most important of the identifiable syndromes and dis­eases were the pneumonia-diarrhea complex of in­fancy and childhood and tuberculosis. Both afflicted Amerindians, blacks, and immigrants more than native-born whites, and both declined in the late nineteenth and twentieth centuries.

Yet even at their zenith in the middle decades of the nineteenth century, mortality rates in North America were low compared with the rates in most ofLatin America half a century later, with the excep­tions noted previously: Uruguay and Argentina, with no indigenous Indian populations and a high proportion of European settlers, and Cuba and Pan­ama, which both benefited and suffered from the presence of the U.S.

The significance of the decline in mortality from midcentury onward is enhanced by the fact that these were the very years during which masses of immigrants from poverty-stricken regions of eastern and southern Europe flocked to the United States and Canada. Although, in general, immigrants had higher mortality rates than native-born people, they tended to have lower mortality rates than were ob­served in their countries of origin (Kunitz 1984).

The very low mortality observed during the colo­nial period is explicable in terms of the dispersed nature of settlement and the fact, supported by data on heights, that the population tended to be well nourished. With the exception of blacks brought as slaves to work on plantations in the South, there was not a large servile class such as existed in much of Latin America. The increase in mortality that seems to have occurred after the colonial period has been attributed to the influx of a large and impover­ished immigrant population living in unsanitary and rapidly growing cities.

What, then, explains the decline in mortality after the Civil War, when an even larger influx of immi­grants every bit as poor as those who had preceded them flooded the cities? It seems likely that the sources of the change were the remarkable productiv­ity of the industrializing U.S. economy and the re­form movements that resulted in sanitary improve­ments in many cities, as well as in small towns and villages (Levison, Hastings and Harrison 1981).

There were, of course, differences in the mortality rates of different cities. By the end of the nineteenth century, these were attributable largely to differ­ences in deaths of infants and young children caused by endemic conditions such as the pneumonia­diarrhea complex. Variations in death rates among cities were explainable by differences in socioeco­nomic measures, except among southern cities, in which the proportion of blacks living in extreme poverty was an important variable (Crimmins and Condran 1983).

In the course of the eighteenth and nineteenth cen­turies, then, there was a shift from epidemics afflict­ing people of all ages to endemic infectious diseases afflicting primarily infants and children. The change occurred earlier in the North than the South, al­though by the 1920s and 1930s, malaria was in de­cline south of the Mason-Dixon line. In the course of the twentieth century, the pneumonia-diarrhea com­plex continued to decline as economic conditions con­tinued to improve, literacy increased, and public health measures were strengthened. By the 1930s tu­berculosis and other infectious diseases caused fewer deaths than cardiovascular diseases and cancer. This change was unrelated to medical therapy, for until the late 1930s such therapy had no discernible effect on mortality (Omran 1977). At that time, however, first sulfonamides and then antibiotics were intro­duced. The result was a small but measurable impact on mortality rates. In the last seven years of the pre­chemotherapy era (1930-7) the age-adjusted mortal­ity rate declined an average of 4.28 deaths per 100,000 population per year. From 1937 through 1954, when antibiotics became widely available, the age-adjusted rate declined on average 19.4 deaths per 100,000 population. From 1955 through 1968 the de­cline all but ceased, averaging 2.1 deaths per 100,000 population per year. At the time many people argued that the decline had ceased because infectious dis­eases had ceased to be a significant cause of death, and the noninfectious and human-made causes of death were refractory to any intervention. It will be recalled that the same explanation was given for the diminution in the mortality decline in Latin America. Beginning in the late 1960s, however, the decline re­sumed. From 1968 to 1978 the average annual decline was 11.8 deaths per 100,000 population, and this de­cline has continued to persist (McDermott 1981).

The decline in mortality since the late 1960s has been accompanied by a shift to later and later ages at death, a pattern sufficiently unusual that some observers have claimed it represents a new and pre­viously undescribed stage of epidemiological history (Olshansky and Ault 1986).

Second, is survival to older and older ages accompa­nied by improvements in morbidity and level of func­tion? On one hand are those who argue that there is a finite life span of about 85 years; that more and more people are living that long in a healthy state; and that they will then die of “natural causes” without linger­ing illnesses. This has been called the “rectangu- larization” of the mortality and morbidity curves (Fries and Crapo 1981). On the other hand are those who argue that 85 does not seem to be the upper limit to the human life span; that the survival of more and more people to older and older ages will be accompa­nied by a disproportionate increase in disability and morbidity; and that the presence Oflingering chronic conditions will impose an enormous cost on the health care system (Schneider and Brody 1983).

Finally, what causes of death have been responsi­ble for most of the decline in mortality at older ages? Although cardiovascular conditions are generally im­plicated, sorting out causes among chronically ill peo­ple with multiple health problems is often difficult.