Stress, adaptation, and enamel developmental defects • 281 



this paper is to begin to consider the meaning of hypoplasias 

 in an adaptive context. I will do this by reviewing two recent 

 studies of enamel hypoplasias in relationship to other indica- 

 tors of stress. One of these studies involves a prehistoric 

 population. If hypoplasias are indications of increased stress 

 and adaptive constraint then we should expect to sec them 

 associated with other indicators of stress. Thus, in the pre- 

 historic study we focus on the relationship between enamel 

 hypoplasias and life expectancy, a universally accepted mea- 

 sure of stress or failure to rally from insults (Goodman, Mar- 

 tin et al. 1984). Finally, because of the limitations of under- 

 standing the adaptive context of dental defects in prehistoric 

 studies, I have begun to examine the pattern of defects in 

 modem, mild-to-moderatcly malnourished children. In the 

 subsequent section I report on the association of defects with 

 socioeconomic status and stature. 



Enamel hypoplasias and longevity 

 at Dickson Mounds 



In order to evaluate the long-term consequences of stress 

 during childhood we have examined the relationship between 

 enamel hypoplasias of permanent teeth and mean age at death 

 at Dickson Mounds (Goodman and Armelagos 1988). The 

 sample consists of 1 1 1 adults and adolescents from the Dick- 

 son Mounds, a multicomponent habitation-burial complex 

 located in Lewiston, Illinois (Goodman, Armelagos, and 

 Rose 1980; Goodman, Lallo et al. 1984). The mounds are 

 associated with three cultural horizons: Late Woodland 

 (LW), Mississippian Acculturated Late Woodland (MALW), 

 and an early and late Middle Mississippian (MM) (Ham 

 1980). During the Late Woodland period (ca. a.d. 900- 

 1050) the area was occupied by a small (75-125) and semi- 

 sedentary hunting and gathering population with seasonal 

 camp sites and an economy directed toward the use of a wide 

 spectrum of ItKal fauna and flora. During the MALW (ca. 

 A.D. I050-1 175) local populations began to come under the 

 influence of Mississippian cultures farther to the south. Dur- 

 ing the MM periodica, a.d. 1 175-1250) the Mississippian- 

 ization of local populations became complete with the 

 culmination of trends toward extended and intensified trade 

 networks, increased population density, size, and sedentar- 

 ism, and greater reliance on maize agriculture (Ham 1978). 

 These changes have been associated with an increase in 

 nutritional and infectious pathological conditions and a de- 

 crease in life expectancy (Goodman, Lallo et al. 1984). Po- 

 rotic hyperostosis typically found on the flat bones of the 

 skull and the superior half the orbits, an indication of iron 

 deficiency anemia, is four times as prevalent among MM 

 subadults as compared to LW subadults (64% to 16%) (Lallo 

 et al. 1977). Periosteal infections in subadults increase from 

 27% in the LW to 81% in the MM (Lallo et al. 1978). and the 

 frequency of enamel hypoplasias doubles in adults and ado- 

 lescents (Goodman. Armelagos, and Rose 1980). Life ex- 

 pectancy is lower at all age intervals in the MM when com- 



Zagnb Paleopathology Symp 1988 



Figure 1. Chronologic enamel hypoplasias (stress-hypo- 

 plasias) on anterior, maxillary permanent teeth. Hypoplasias 

 are observable on right central incisor, right and left lateral 

 incisors, and right and left canines. All hypoplasias occur 

 between 3.0 and 3.5 years developmental age and appear to 

 be the result of the same systemic dismption (stress). 



pared to the combined LW and MALW samples (Moore et al. 

 1975). 



Enamel hypoplasias were recorded on all permanent teeth 

 except third molars as circumferential lines, bands, or pitting 

 of decreased enamel thickness (Goodman, Armelagos, and 

 Rose 1980) (Figure 1 ). The distance of the hypoplasia from 

 the cemento-enamel junction was measured to 0. 1 mm using 

 a thin-tipped caliper. This distance measure was converted to 

 the individual's dental age when the dismption occurred, 

 based on the developmental standard of Massler et al . ( 1 94 1 ). 



Each half-year period between birth and 7.0 years was 

 rated as either stress-positive, stress-negative, or undeter- 

 mined, based on the following criteria: ( 1 ) a half-year period 

 was rated as stress-positive if there were two or more teeth 

 with hypoplasias occurring during the half-year period; (2) a 

 half-year period was rated as stress-negative if less than two 

 hypoplasias occurred during this period and at least four 

 tooth crowns were available for scoring whose development 

 includes this period; (3) a half-year period was rated as un- 

 determined if one or no hypoplasias occurred during this 

 period and there were less than four tooth crowns available 

 for scoring whose development included this period. By 

 using this method, a chronology of stress by half-year peri- 

 ods was developed for each individual from birth to 7 years of 

 age (Goodman. Amielagos. and Rose 1980.1984). 



This study is based on the evidence for stress between 3.5 

 and 7.0 years of age. The extensive dental attrition limits 

 ability to observe the enamel record of stress from birth to 3.5 



