Traditional interpretations of health in the past were based on the assumption that high levels of stress indicators within a population were representative of the most disadvantaged and unhealthy, while low levels were thought to represent more advantageously healthy
individuals (Cohen 1989; Armelagos 1990; Allison 1984; Cohen and Armelagos 1984; Goodman
et al. 1984a; 1988; Armelagos et al. 1999). However, Wood et al.’s (1992) influential work
challenged this conventional wisdom. They highlighted that in order for a stress marker to be observed, an individual must be able to adapt and live for a sufficient amount of time for osseous changes to manifest within bones or teeth (Wood et al. 1992; also Harpending 1990; Ortner 1991; 1992; 2003: 113). Therefore, those individuals with stress indicators may represent individuals with “healthier” immune systems, with those least able to adapt, dying before skeletal changes could occur (Wood et al. 1992: 345). This hypothesis, referred to as the “osteological paradox”, suggests that rather than being viewed as indicators of poor health, skeletal stress indicators should be seen as indicative of a good adaptive immune response (Ortner 1991: 10). Wood et al. (1992: 345) stress that as a result of this, there is a possibility that those individuals who died before skeletal lesions could develop could be conflated with those individuals who show no skeletal lesions due to advantageous buffering. Remodelling of skeletal lesions over time may also remove traces of stress indicators, further obscuring patterns of stress within a population. A notable exception to this is enamel
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hypoplasia, as the enamel in which it is formed does not remodel (Goodman and Rose 1990; Aufderheide and Rodríguez-Martín 1998: 406; Armelagos et al. 2009).
Furthermore, when attempting to understand past subadult health, it is important to consider that the skeletal assemblages available for analysis represent a biased cross-sectional sample of those individuals who failed to attain adulthood – the “non-survivors” (Wood et al. 1992: 349; Saunders and Hoppa 1993: 128; Lewis 2007: 103). Within a population, not all individuals within an age cohort will be exposed to the same risk of death (frailty), due to inherent
differences of biology and differential exposure to environmental and cultural risks. As a result of this difference in frailty, those subadults less adapted to these constraints and most at risk of stress at a particular age are more likely to enter the skeletal record than their less frail counterparts (Bolsden and Milner 2012: 121-122; DeWitte and Stojanowski 2015: 11). This selective mortality means the morbidity and mortality risks observed amongst these “non- survivors” may be unrepresentative of the once-living subadult population and may even lead to an overestimation of the prevalence rates of skeletal lesions in the past (Wood et al. 1992: 349; Saunders and Hoppa 1993; Lewis 2002: 2; DeWitte and Stojanowski 2015: 11). Identifying the level of frailty within a skeletal population is near impossible (“hidden heterogeneity”), making it difficult to infer patterns of mortality, morbidity and stress indicator prevalence in the general population (Wood et al. 1992).
While responses to the “osteological paradox” acknowledge the issue of selective mortality and frailty, the wholesale reinterpretation of stress indicators as evidence of better health has been challenged (Lukacs 1992; Wilkinson 1992; Goodman 1993; Jackes 1993; Cohen 1994). For example, Cohen (1994) argues an overall decline in health is a more probable interpretation of the increased stress indicator prevalence rate observed with the movement to sedentism in American prehistoric populations. Cohen (1994: 631) also challenged the idea that the patterns of stress indicators within a population are unrepresentative of the lived population as many deaths may be accorded to random events. However, this has been subsequently refuted (Wood and Milner 1994: 634). Goodman (1993) also maintains that the osteological paradox overstates the importance of hidden frailty and selective mortality due to a failure to consider cultural and biological processes. For example, by considering age and mortality when interpreting stress indicator prevalence, Goodman (1993: 283) shows it is possible to separate those individuals without lesions due to increased frailty from those without lesions due to better health. Furthermore, Goodman (1993) stressed the importance of interpreting multiple stress indicators to properly understand patterns of health. In response to these criticisms, Wood and Milner (1994) identify their observation that stress indicators may indicate better health is not necessarily more correct than traditional interpretations. Instead, they state that
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both outcomes are equally plausible, with the original article drawing attention to potential problems that were previously overlooked (Wood and Milner 1994: 636). The osteological paradox continues to be a subject of discussion within bioarchaeological literature and many of the problems it highlights still remaining unresolved (Wright and Yodder 2003; Bolsden and Milner 2012; DeWitte and Stonjanowski 2015). However, the best approach to meeting these concerns is considered to be a holistic approach that analyses multiple stress indicators within its archaeological context (Goodman and Martin 2002: 13).
DeWitte and Stojanowski (2015) also suggest that one way of identifying frailty within a subadult population is to compare stress indicator prevalence rates among subadults. For, if stress prevalence rates are higher in early childhood than late childhood, the pattern would conform to the conventional wisdom, whilst higher prevalence rates would indicate lower frailty with increased age in accordance with the osteological paradox (DeWitte and
Stojanowski 2015: 21-23). Such studies within the bioarchaeological literature have found both patterns (Wright and Chew 1998; Bennike 2005; Perry 2014) as well as no connection between age and stress indicators (Saunders and Hoppa 1993; Cucina et al. 2011), indicating the
importance of understanding the archaeological context within which the stress indicator prevalence rates must be interpreted (DeWitte and Stojanowski 2015).