1. Public Health Medicine, Northern and Yorkshire Regional Training Scheme, County Durham Health Authority, Lancaster Road, Durham DH1 5XZ, UK
2. Australian Research Centre in Sex, Health and Society, La Trobe University, 215 Franklin St, Melbourne 3000, Australia
3. Department of General Practice and Public Health, University of Melbourne, 200 Berkley St, Carlton 3053, Australia
4. BreastScreen Victoria, 31 Pelham St, Carlton South 3053, Australia