Abstract
The Caerphilly and Speedwell studies are based on representative samples of over 3000 subjects in South Wales and over 2000 in Bristol. They include cross sectional studies of risk factors for prevalent ischaemic heart disease (IHD) and of determinants of those risk factors. Prospective studies based on over 2000 men aged 45-59 in each area have been set up. In addition to the examination of lipid and thrombosis factors of possible relevance to IHD, the studies also focus on possible dietary, hormonal, and psychological risk factors, both as possible "risk factors" for IHD and also as possible "determinants" of risk factors.