Open Access. The published version of this work has been reproduced here according to the publisher's polices.
Rights
This article may be downloaded for personal use only. Any other use requires prior permission of Elsevier (Lancet Publishing Group). This article was first published in the Lancet, 375(9732): 2152-2160, 2010 and may be found at http://dx.doi.org/10.1016/S0140-6736(10)60587-9 (Please note: access via this link may only be available with a subscription)
Rights
Copyright (2013) Elsevier B.V. All rights reserved.