About the Authors
Department of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
The authors have declared that no competing interests exist.
IdSS, BDS, and VM designed the study. All members of the Collaborative Group contributed to data acquisition, with final data checking and standardisation by BDS and VM. BDS performed statistical analysis of data. IdSS, BDS, VM, and all members of the Collaborative Group interpreted the findings. IdSS and BDS had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. IdSS prepared the first draft of the manuscript. All authors provided comments in writing the paper.