The Journal of Epidemiology and Community Health is a truly international journal that encompasses all aspects of epidemiology and public health. It publishes original research, opinions and materials concerned with the study and improvement of communities worldwide. * The purpose of this podcast is to educate and to inform. The content of this podcast does not constitute medical advice and it is not intended to function as a substitute for a healthcare practitioner’s judgement, patient care or treatment. The views expressed by contributors are those of the speakers. BMJ does not endorse any views or recommendations discussed or expressed on this podcast. Listeners should also be aware that professionals in the field may have different opinions. By listening to this podcast, listeners agree not to use its content as the basis for their own medical treatment or for the medical treatment of others.