286 • Alan H. Goodman 



with the fact that the hypocalcification rates found in Solis 

 are in hne with other low-tluoride areas with much greater 

 access to resources. 



The degree of association between hypoplasias and nutri- 

 tion and socioeconomic status, however, reaffirms the notion 

 that they are related to general conditions of life. These data 

 are consistent with prior experimental and epidemiological 

 data on hypoplasias and nutritional status. Sweeney and co- 

 workers (1971), for example, have linked deciduous hypo- 

 plasias to second and third degree malnutrition, measured by 

 growth status, in Guatemalan children. Our study extends 

 from Sweeney's in focusing on permanent tooth defects, a 

 less severe degree of malnutrition and, we believe, less se- 

 vere hypoplasias. 



Discussion 



Based on the results of these two studies it is suggested that 

 enamel hypoplasias are indicators of increased stress and 

 adaptative constraint. The general assumption that those with 

 hypoplasias are exposed to more stress than those without (or 

 are less able to rally from this stress) is warranted. While 

 these indicators do not cause death, they are associated with 

 hardship and, therefore, are important factors in elucidation 

 of the human condition. 



But, what level of infirmity is associated with enamel 

 hypoplasias? Based on the Mexico data, it is clear that enam- 

 el hypoplasias are common under typical conditions of en- 

 demic mild-to-moderate malnutrition. Under these condi- 

 tions one can expect decreases in functions, such as work 

 capacity, sociability, and immune resistance (Chavez and 

 Martinez 1982). The prevalence of defects found in pre- 

 historic populations, which is usually greater than that found 

 in the Mexico study, projects to similar functional effects. 



While enamel hypoplasias suggest an important stress, can 

 we say the same for other paleopathological conditions? Do 

 Harris's lines connote an increase in the burden of morbidity? 

 Do arthritic and osteoporotic lesions dictate losses in ability 

 to work and in other functional capacities? Do the infectious 

 and nutritional conditions thought to be causative, at least in 

 part, of periosteal lesions and porotic hyperostosis signify a 

 decrease in adaptation? 



In order to answer these questions researchers need to 

 address fundamental issues regarding the cause of lesions in 

 both environmental and biological terms. In order to better 

 appreciate the functional and adaptive meaning of any 

 growth disturbance (Harris" lines, enamel hypocalcifica- 

 tions, skull base height, etc.) the environmental conditions 

 causative of these lesions must be clearly understood. If they 

 are secondary to rather rapid infectious episodes, then the 

 impact on function may be equally short lived. However, if 

 the conditions strike at critical periods and are relatively 

 longer lasting, then permanent damage might result. 



The effect of a stressor on an organism is due not only to 

 the characteristics of the stressor, but to the organism's bio- 

 logical response to the stressor (Selye 1973). Therefore, it is 

 equally critical to understand the severity, duration, and qual- 

 ity of the response summoned by the organism (Thomas et al. 

 1979). Some infections, perhaps causative of periosteal reac- 

 tions, might elicit an appropriate immunological response 

 leading to little or no lasting and detrimental effects (Ortner 

 1979). Other conditions, such as endemic parasitism, might 

 lead to disruptions in work and reproductive capacities, but 

 will leave no indications on hard tissue. Still other conditions 

 such as endemic undernutrition might cause a mild porotic 

 hyperostosis, which does not match the severity with which a 

 wide spectrum of functional capacities are inhibited. In 

 short, paleopathological conditions are likely to differ in their 

 adaptive and functional meaning depending on the charac- 

 teristics of the stressors causative of the lesion, the underly- 

 ing condition of the organism, and the responses elicited by 

 the organism to the stressful condition. Furthermore, the 

 severity of a lesion might not be easily equated with a sever- 

 ity of functional effects. If we wish to understand the adap- 

 tive and functional meaning of paleopathological lesions 

 then we need to better understand the environmental contexts 

 in which they occur and the biological responses which lead 

 to their formation. 



Given the magnitude of the problem of undernutrition and 

 associated lesions, both now and in prehistory, it is reason- 

 able to work toward the development of easily implement- 

 able measures of nutritional status. Enamel defects have 

 unique strengths of being time specific and indelible, con- 

 trasting with more standard nutritional status indicators. Re- 

 searchers are encouraged to continue to study these defects in 

 prehistory. While there are large gaps in our understanding of 

 these defects, one can make important inferences based on 

 patterns of dental defects. Finally, studies of these defects in 

 experimental and epidemiological contexts will help to eluci- 

 date contemporary and prehistoric conditions. 



In conclusion, this study has reatfirmed the notion that 

 enamel hypoplasias are related to general conditions of life in 

 marginal environments. It is hoped that studies of enamel 

 defects in living populations will both help us to understand 

 the significance of these defects in prehistory and become 

 important in their own right as tools for understanding the 

 stresses of contemporary conditions. Fifteen years ago 

 Jelliffe and Jelliffe concluded that "further study of its (enam- 

 el hypoplasias') etiology and public health consequences 

 seems overdue" (1971:893). This plea remains appropriate. 



Literature cited 



Allen, L.H.. A. Chavez, andG.H. Pelto. I9S7. ColUthomtive Re- 

 search and Support Project on hood Intake and Function. Mexico 

 Project Final Report. Washington, D.C.; United States Agency 

 for International Development. 



Zagreb Paleopathotngy S\mp. 1988 



