1. European Centre for Environment & Human Health, University of Exeter Medical School, Truro, United Kingdom.
2. George Alleyne Chronic Disease Research Centre, The University of the West Indies, Bridgetown, Barbados.
3. Send correspondence to Catherine Brown, catherine.brown@cavehill.uwi.edu
4. Medical Research Council Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom.
5. School of Public Health, Massey University, Wellington, New Zealand.