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M (2015) Infant mortality and isotopic complexity: new approaches to stress, maternal health and weaning. American Journal of Physical Anthropology. 157(3): 441-457, which will be published in final form at http://dx.doi.org/10.1002/ ajpa.22736. Materials and MethodsChildhood dentine collagen  13C and  15N profiles were produced from horizontal sections of permanent and deciduous teeth following the direction of development. These were from two 19 th -century sites (n = 24) and a small number (n = 5) of prehistoric samples from Great Britain and Ireland. ResultsThese high-resolution data exhibit marked differences between those who survived childhood and those who did not, the former varying little and the latter fluctuating widely. DiscussionBreastfeeding and weaning behavior have a significant impact on the morbidity and mortality of infants and the adults they become. In the absence of documentary evidence, archaeological studies of bone collagen of adults and juveniles have been used to infer the prevalence and duration of breastfeeding. These interpretations rely on certain assumptions about the relationship between isotope ratios in the bone collagen of the adult females and the infants who have died. The data from this study suggest a more complex situation than previously proposed and the potential for a new approach to the study of maternal and infant health in past populations. 3Carbon and nitrogen stable isotope ratios from archaeological bone and dental tissues have been used for more than 20 years to investigate breastfeeding and weaning practices. Early studies, which revolutionized the use of bone collagen stable isotopes, identified patterns within the tissues of fetuses (less than 28 weeks gestation), neonates (28-40 weeks gestation) and infants (28 days to 1 year post-birth)(Lewis and Gowland 2007) which revealed the potential to investigate the duration of breastfeeding and weaning in past populations (e.g. Fogel et al. 1989;Katzenberg et al. 1993;Schurr 1997;White and Schwarcz 1994). Katzenberg (1996) reviewed previous interpretations of the method and cautioned against the potential effect of using the tissues of dead infants without knowing the cause of death and the potential for stress, bone turnover and growth to alter the isotope ratios of both mother and infant. Subsequently, a simplified method, based on a mathematical model of the isotope ratio variations which should be associated with a dietary change from breastmilk to the prevailing diet of the adult population, was proposed and widely accepted (Schurr 1997;Millard, 2000;Jay, 2008). This method has since been applied to data from modern, historical and archaeological tissues to estimate the timing of weaning and whether breastfeeding occurred over prolonged periods.The mathematical model has been used pragmatically despite the often-acknowledged fact that it makes several assumptions about the relationships of mother and infant body tissues, their diets, and the comparability of individual members of a population with the o...

ObjectivesRecent developments in incremental dentine analysis allowing increased temporal resolution for tissues formed during the first 1,000 days of life have cast doubt on the veracity of weaning studies using bone collagen carbon (δ13C) and nitrogen (δ15N) isotope ratio data from infants. Here, we compare published bone data from the well‐preserved Anglo‐Saxon site of Raunds Furnells, England, with co‐forming dentine from the same individuals, and investigate the relationship of these with juvenile stature. The high‐resolution isotope data recorded in dentine allow us to investigate the relationship of diet with juvenile stature during this critical period of life.Materials and methodsWe compare incremental dentine collagen δ13C and δ15N data to published bone collagen data for 18 juveniles and 5 female adults from Anglo Saxon Raunds Furnells alongside new data for juvenile skeletal and dental age. An improvement in the method by sampling the first 0.5 mm of the sub‐cuspal or sub‐incisal dentine allows the isotopic measurement of dentine formed in utero.Results and discussionδ13C profiles for both dentine and bone are similar and more robust than δ15N for estimating the age at which weaning foods are introduced. Our results suggest δ15N values from dentine can be used to evaluate the maternal/in utero diet and physiology during pregnancy, and that infant dentine profiles may reflect diet PLUS an element of physiological stress. In particular, bone collagen fails to record the same range of δ15N as co‐forming dentine, especially where growth is stunted, suggesting that infant bone collagen is unreliable for weaning studies.

Context: Adult age-at-death is presented in a number of different ways by anthropologists. Ordinal categories predominate in osteoarchaeology, but do not reflect individual variation in ageing, with too many adults being classified as 'middle adults'. In addition, mean ages (derived from reference samples) are overly-relied upon when developing and testing methods. In both cases, 'age mimicry' is not adequately accounted for.Objectives: To highlight the many inherent biases created when developing, testing and applying age-estimation methods without fully considering the impact of 'age mimicry' and individual variation.Methods: The paper draws on previously published research (Web of Science, Pub Med, Google Scholar) on age estimation methods and their use in anthropology.Results and Conclusions: There is a lack of consistency in the methods used to estimate age, and for the mode of combining them. Ordinal categories are frequently used in osteoarchaeology, whereas forensic anthropologists are more likely to produce case-specific age ranges. Mean ages reflect the age structure of reference samples, and should not be used to estimate age for individuals from populations with a different age-at-death structure. Individual-specific age ranges and/or probability densities should be used to report individual age. Further research should be undertaken on how to create unbiased, combined method age estimates. 2Age estimation of adults remains one of the most complex, yet essential, aspects of human skeletal analysis (Aykroyd et al. 1997;Bocquet-Appel and Masset 1982; Hoppa and Vaupel 2002a;Konigsberg and Frankenberg 1992;Milner et al. 2008). In a society ruled by numbers, we are eager to ascribe a specific age to skeletonised remains, either to facilitate the identification of unidentified remains in a forensic situation, or to better interpret the life, death and burial of archaeological humans. Yet many methods of age estimation, especially for adults but also for non-adults, are woefully inadequate at producing point age estimates. Over the last few decades, research into the development, refinement and testing of adult age-estimation methods has expanded, resulting in a plethora of techniques, and variants of techniques, available for application, with the aim of improving accuracy and precision.Age estimation in non-adults, where dental and skeletal maturation are employed to estimate chronological age, typically produces estimates that are both accurate and precise. Dental development in particular has been shown to be minimally affected by external factors such as disease or malnutrition (Elamin and Liversidge 2013) and thus less variation in age for a specific stage of development. Once skeletal maturity has been reached, age is typically estimated using degenerative changes of the skeleton, dental wear and (less frequently) microscopic analysis of bone and cementum. All of these, except tooth cementum annulations, have only a broad relationship with chronological age (Gauthier and Schutkowski 2013;Gro...

Bradford Scholars -how to deposit your paper Overview Copyright check• Check if your publisher allows submission to a repository.• Use the Sherpa RoMEO database if you are not sure about your publisher's position or email openaccess@bradford.ac.uk.