Early Life and adult disorder: research themes

Correspondence fo: Prof. M G Marmot, International Centre for Health and Society, Department of Epidemiology and Public Health, University College London Medical School, 1 ?9 Torrtngton Place, LondonWClE6BT,UK This series of papers is about the role factors operating early in life may play in the cause of mental and physical disease in adulthood. Genes are the endowment coming from the earliest moment, when sperm penetrates ovum, that have an obvious influence carrying over into later life. They shape appearance and physiological function and, according to the new findings of behavioural genetics, influence how people think and act. Their influence, relative to environment, over the pattern and occurrence of disease in later life is still the subject of vigorous debate. The debate has, of late, taken a new form. There may be influences from early life that influence adult disease rates that are environmental, not genetic. These may act in utero or during infancy, childhood and adolescence. The debate is, therefore, not only of the relative importance of genes versus environment but of the relative importance of early environment versus later environmental exposures. No student of Freud has any doubt that early psycho-social environment has effects on subsequent mental health. Indeed, much of psychoanalysis is devoted to reversing the effects of early environmental exposures. In neuroscience, the concept of the critical period has had profound effect; i.e there is a period in development of an individual's brain during which it develops certain capacities if exposed to appropriate environmental stimuli; or perhaps fails to develop others if it is not exposed to the appropriates stimuli. If the capacity is not developed at the appropriate time, the lack carries over into adulthood. Barker has suggested that there may be similar critical periods in other organ systems. Exposures at this crucial time in development may have profound effect on susceptibility to disease in later life. There may be programming. Rubella, thalidomide..., we are in no doubt that influences on the mother in pregnancy can have dramatic influence on pathology in the offspring that stay with them for the rest of their lives. It is also clear that influences on the mother such as smoking, malnutrition, drug and alcohol abuse can influence outcome of pregnancy. What has been considered to a lesser extent is the influence of these more 'subtle' effects on subsequent health and disease. The chapters gathered in this issue explore aspects of the influence from early life on adult pathology. The purpose of this chapter is to pick