Entangled lives: Implications of the developmental origins of health and disease hypothesis for bioarchaeology and the life course.

Epidemiological research since the 1980s has highlighted the consequences of early life adversity, particularly during gestation and early infancy, for adult health (the "Barker hypothesis"). The fast-evolving field of molecular epigenetics is providing explanatory mechanisms concerning phenotypic plasticity in response to developmental stressors and the accumulation of disease risk throughout life. In addition, there is now evidence for the heritability of poor health across generations via epigenetic modifications. This research has the potential to invoke a paradigmatic shift in how we interpret factors such as growth insults and immune response in past skeletal remains. It demonstrates that health cannot be understood in terms of immediate environmental circumstances alone. Furthermore, it requires both a theoretical and practical re-evaluation of disease biographies and the life course more generally. Individual life courses can no longer be regarded as discrete, bounded, life histories, with clearly defined beginning and end points. If socioeconomic circumstances can have intergenerational effects, including disease susceptibility and growth stunting, then individual biographies should be viewed as nested or "embedded" within the lives of others. This commingling of life courses may prove problematic to unravel; nevertheless, this review aims to consider the potential consequences for bioarchaeological interpretations. These include a greater consideration of: the temporal power of human skeletons and a life course approach to past health; infant health and the implications for maternal well-being; and the impact of non-proximate stressors (e.g., early life and ancestral environments) on the presence of health indicators.