Trinational case–control study of oral contraceptives and health

The collaboration of Dr Neil Poulter and Professor Michael Marmot, both of the Department of Epidemiology and Public Health, University College London Medical School, was crucial for the preparation of the present research protocol. In particular, we made extensive use of a protocol prepared by Dr Poulter and Professor Marmot for the World Health Organization, entitled ‘WHO multicentre case–control study of cardiovascular disease and steroid hormone use’ during the feasibility study carried out in 1991.