HEALTH

Statistics of Health

JAMES M. HUNDLEY.

BIRTHS, deaths, disease rates, longevity, and other aspects of health that can be expressed statistically are used almost universally to assess and follow the status of people's health.

Statistics are simply barren figures, however, and we have to relate or compare them to something else before they have life and meaning. Since no one knows what level of health may be attainable ultimately, vital statistics are most useful in showing trends, detecting changes or problems, and comparing conditions of health. They help us determine what has been accomplished and what remains to be done.

Among the most important vital statistics are those that pertain to the growth of population. The population of the United States was estimated at about 75 million in 1900. It was 130 million in 1940 150 million in 1950, and 177 million on June 14, 1959. If current trends continue, the population will exceed 220 million in 1970.

A few of the figures for 1955 may not be strictly comparable to 1900 data because of a change in the classification of diseases and change in reporting systems.

This remarkable rate of the growth reflects first of all the numbers of births and deaths. Immigration accounted for considerably less than 10 percent of the increase in recent years.

The birth rate was less than 20 per 1 thousand in the 1930's. It was at a fairly steady level of about 25 during the 1950's. That was not much above the level in 1925; about 1 million more children are now born every year, but that is an increase in number, due to the larger total population, and not in the rate itself. It is interesting to note that the estimated birth rate in 1910 was about 30.

Meanwhile the death rate has dropped spectacularly. Except during 1918, when influenza was pandemic, the rate has trended downward, from 17.2 in 1900 to 9.4 in 1956.

Even more striking is the decline in infant mortality (under 1 year of age), which was 162.4 per 1 thousand live births in 1900 and less than 30 in 1955.

Since the birth rate was about 25 in 1959 and the mortality rate about 10, the net population gain was about 15 (per 1 thousand population), a rate of increase of 1.5 percent a year. That is lower than the rates in some of the other countries in the Americas, where increases of 3 percent a year are recorded, but higher than in most of Europe and higher even than in some major Asian countries, such as India. Some of the reasons for the major drop in the death rate are evident in comparing the 10 leading causes of death in 1900 and the mortality in later years from those diseases. The figures are given in an accompanying table. The spectacular decline in disease of infectious origin is the main point to note.

These striking decreases in mortality are reflected in figures of life expectancy. The average life expectancy was about 47 years in 1900. It was 69.3 years in 1957. In a little more than a decade, 5 years have been added to man's expected span.

These gains in health have been shared by most of the economically well-developed countries. In many countries, however, malnutrition and disease continue to exact heavy tolls. Average life expectancies are 35 to 45 years in many of them.

Other types of statistics also have some relationship to nutrition the incidence of premature babies and maternal mortality, for example. At this point, however, it is pertinent to ask what these statistics mean in terms of nutrition.

Data like those I have given often are used to estimate the probable nutrition situation of a population. In countries where malnutrition is widespread, there is no doubt that nutrition is a major factor in most of the usual vital statistics, but it must be remembered that these statistics are influenced by many factors other than nutrition.

Endemic and epidemic diseases, sanitation, the adequacy of medical care, and the public health facilities exercise major influences. The better medical care that can be given mother and infant in a modern hospital, for instance, unquestionably has been a leading factor in reducing the infant mortality rates in the United States, where 94 percent of all deliveries occur in hospitals.

Deaths among boys and girls 1 to 4 years old in many ways are better indicators of nutritional status than infant mortality is. It is the period when infants change from breast, formula, or other special feeding to the food available to other members of the family. Protein malnutrition then takes a toll in many countries.

That mortality among children 1 to 4 years old is largely preventable is shown by the spectacular decreases in this country. Mortality rates between 1 and 4 were 19.8 per 1 thousand in 1900. The rate in 1955 was 1.1 almost a twentyfold decrease. Mortality in this age group continues high in many countries with major nutrition problems for example, Mexico, 27.8; Brazil, 16.2; and Egypt, 49.7 (1947 data).

Even in this group, however, many factors besides nutrition influence mortality. The same must be said of tuberculosis mortality, where nutrition is an important factor. Total deaths from tuberculosis in this country exceeded 80 thousand in 1930 and were less than 20 thousand in 1954. The decline has been especially sharp since about 1945 probably due mainly to better therapy.

This decline in tuberculosis mortality has occurred despite the fact that total new cases reported annually have declined only a little since 1930. The illness now tends to be shorter in duration and less severe.

Other types of statistics, such as rates of occurrence of specific nutritional disease, would be more specific indicators of nutritional change. Such diseases are not reportable, as are many of the infectious diseases. Only death rates are available, and they have declined to the point where they have little meaning as indicators of changes in nutrition.

Deaths reported from various nutritional diseases are listed in the second table. The main points to note are the decline in deaths from pellagra and rickets and the low incidence of all types of nutritional deaths in 1956.