1. Gita D Mishra, MRC Unit for Lifelong Health & Ageing, University College & Royal Free Medical School, 33 Bedford Place, London, WC1B 5JU, UK, Tel.: +44 207 670 5712, Fax: +44 207 580 1501,
2. Rachel Cooper, MRC Unit for Lifelong Health & Ageing, University College & Royal Free Medical School, 33 Bedford Place, London, WC1B 5JU, UK, Tel.: +44 207 670 5714, Fax: +44 207 580 1501,
3. Sarah E Tom, Laboratory of Epidemiology, Demography & Biometry, National Institute on Aging, Bethesda, MD, USA, Tel.: +1 301 496 6117, Fax: +1 301 496 4006,
4. Diana Kuh, MRC Unit for Lifelong Health & Ageing, University College & Royal Free Medical School, 33 Bedford Place, London, WC1B 5JU, UK, Tel.: +44 207 670 5701, Fax: +44 207 580 1501,