Arterial disease that underlies stroke and heart attacks begins in childhood. Changes in the arterial structure and function are seen as early as age 10. We plan to examine which genetic and environmental factors are important at the onset of disease in a well characterised cohort of 7,507 9-11 year old children from the ALSPAC study, in whom we have made detailed measurements of arterial structure and function. This will help to understand the respective contributions of well-known risk factors, such as cholestrol and blood pressure, as well as novel influences such as inflammation and obesity. Better risk prediction and new opportunities for treatment should result.