Social and biological pathways linking early life and adult disease.

Evidence is presented for a pathways model linking early life factors and adult disease, which takes account of the inter-relationships between social and biological risks throughout the lifecourse. Few studies, if any, have yet recorded adequate birth to death information which could be used to quantify the effects of different factors and their timing. Hence, there is only limited understanding of the extent to which biological and social risks experienced at different life stages combine to influence adult disease. However, some of the pathways between early and later life are suggested when evidence from earlier stages of the lifecourse is linked to that from studies at older ages, in which adult disease risk factors have been established. Further support for pathway effects is provided by studies showing that health outcomes of early biological insults can depend on the subsequent social and biological environment. Thus, it is argued that adult disease will be more fully understood when account is taken of the combined effects of social and biological risk occurring at different life stages.