Anthropometry

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ANTHROPOMETRY

Anthropometry is the science of human body measurement. Anthropometric data include measures of length, breadth, and weight of the body, circumferences of body parts, amounts of muscle and fat, the weight and size of body organs, and the size, shape, and density of bones. Many anthropometric measurements can be taken on the living, some may be taken on skeletal samples from historical burials or archaeological contexts, and other measurements are only feasible from autopsy after death. Anthropometric data are used in population research to understand the health, social, economic, and political conditions of groups of people, especially when conventional indicators (e.g., medical records, extent of schooling, gross domestic product, real wages) are not available. Such groups of people include most historical populations, slaves, archaeological populations, and many people alive today living in traditional cultures.

Kinds of Anthropometric Measures

Table 1 lists several kinds of anthropometric measures, their meaning, and methods of assessment. Height is a measure of the total history of growth of the individual. Centimeters of height accumulate over time and are the product of complex biological, behavioral, and ecological interactions. Weight represents total body mass and is a measure of recent events. Weight is more labile than height to short-term influences of diet, activity, and health. Weight may decrease over time, but height does not do so, at least during the first decades of life. The height and weight of any single individual is not of much use in population studies, but the heights and weights of many individuals from a defined group may reveal a great deal of information. Expected amounts and rates of growth in height and weight for healthy individuals at given ages from birth to maturity are well established.

These data may be used as references to compare the growth of members of the particular group under study. Significant deviations from the reference usually indicate some ecological disturbance to growth, such as poor nutrition, disease, abnormal lifestyle, psychosocial problems, and even war. Genetic disturbances to growth are well known, but usually affect individuals and not whole populations. Variations in physical growth and population structure are sensitive indicators of the quality of the environment and may be used as a mirror, reflecting rather accurately the material and moral conditions of that society.

Interpreting Anthropometric Data

Reference data are also available for virtually all anthropometric measures, and as is the case for height and weight, such references may be used to interpret the determinants of growth and development. The length of body segments (such as sitting height), thickness of skinfolds, and circumferences are used to characterize body proportions and body composition, especially the amount of muscle and fat. These measures provide more detailed evidence of health or disturbances to growth; for example, adults with short legs relative to total stature often experienced malnutrition and disease during infancy and childhood.

Radiographs reveal the degree of formation of the skeleton. The amount of skeletal maturation provides an indication of biological age, which is not identical to chronological age. Early maturers will have more advanced skeletal development than late maturers. Rate of maturation influences many biosocial capacities of the individual, including fertility. Rate of maturation may in turn be influenced by environmental quality. Finally, handgrip strength provides a measure of total physical fitness, especially as it relates to physical work capacity. In populations in which physical labor is important, greater size, skeletal maturity, and strength lead to greater productivity.

Anthropometric measurements can be collected relatively quickly and inexpensively. When properly collected, they are safe, painless, and minimally invasive. Still, taking measurements requires the cooperation, understanding, and informed consent of all participants. As children are often the subjects of growth studies it is necessary that the guardians of these children (parents, school authorities) be fully informed as to the nature of the measurements and the purpose of the research, and provide consent for the measurements. More generally, sensitivity by those conducting the research to the cultural values of the subjects is essential.

Anthropometric Data in Population Studies

An example of the use of anthropometric data in population studies comes from a survey of 8,000 years of human growth in Latin America. The data

TABLE 1

are for 597 samples of adult height for men and women, representing 32,922 individual measurements of stature on the living or estimates of stature from archaeological and cemetery samples. The people are Native Americans and low socioeconomic status mestizos (people of mixed Spanish and Native American heritage). The data and main trends in height are presented in Figure 1. The data were analyzed by plotting the mean value for each sample and then fitting a distance-weighted least square regression line, a type of average curve.

The oldest data in this set are for skeletal remains of a foraging people living along the coast of Ecuador. These people ate a wide variety of foods, including abundant fish and shellfish, and lived in relatively small social groups, with low population density. Their bones, teeth, and stature all indicate that they were relatively healthy. The next group includes the remains of horticulturists from Peru. They produced a wide variety of garden foods, and also hunted and gathered wild animal and plant foods. The density of the population was low to moderate, and the people seem to have been organized into tribal-type groups, with minimal social stratification. Their growth shows evidence of increasing adaptation to sedentary life and improvement of nutrition and health.

The data from 1,000 b.c.e. to 1750 c.e. come from people who practiced intensive agriculture. Several lines of evidence indicate that, overall, these people experienced reductions in stature, longevity, and health compared with the earlier periods. Agriculture may have produced a more monotonous and lower quality diet for the majority of people. The people also lived in larger and denser populations with more intensive and invasive social and political control, and strong social stratification. The social differences are expressed in stature, as the political elites were the tallest men and women in the samples. After 1500 c.e., average statures decline rapidly as a consequence of the European conquest and the social and biological insults that were imposed on the native people. During the historic period (after 1873) most Latin Americans lived by means of subsistence agriculture and wage labor. Politically, the general tendency was to have systems of local dictatorship,

FIGURE 1

with economic exploitation by European and North American countries. The health and nutrition of Amerindians and rural mestizos suffered under this system. These conditions remained in place up through the first half of the twentieth century in much of Latin America. The worldwide economic depression of the 1930s intensified these already deleterious conditions for the biological, economic, and social well being of Native Latin Americans. The negative trend in stature until 1939 may be a consequence of these environmental conditions.

The positive trend in stature from 1940 to 1989 is associated with the worldwide economic recovery sparked by World War II. Latin America benefited from this recovery and did not suffer the ravages of the war in Europe, Asia, and the Pacific. Postwar economic growth continued, especially with foreign investment. This expanded economies, helped to increase the rate of urbanization, and the redistribution of the population via rural-to-urban migration. The positive trend for stature may be an outcome of these changes in the standard of living and demographic structure.

Conclusion

These brief examples, and many others like them, show how anthropometric data serve population studies as general measures for the quality of life, as quantitative economic indicators of the standard of living, and as summary measures of human welfare.

bibliography

Bogin, Barry. 1999. Patterns of Human Growth, 2nd edition. Cambridge, Eng.: Cambridge University Press.

——. 2001. The Growth of Humanity. New York: Wiley-Liss.

Bogin, Barry, and Ryan Keep. 1998. "Eight Thousand Years of Human Growth in Latin America: Economic and Political History Revealed by Anthropometry." In The Biological Standard of Living and Economic Development: Nutrition, Health, and Well Being in Historical Perspective, ed. John Komlos and Joerg Baten. Munich: Fritz Steiner.

Tanner, James M. 1986. "Growth as a Mirror for the Conditions of Society: Secular Trends and Class Distinctions." In Human Growth: A Multidisciplinary Review, ed. Arto Demirjian. London: Taylor and Francis.