About the Authors
Department of Social Medicine, University of Bristol, Bristol, United Kingdom
Medical Research Council Centre for Causal Analyses in Translational Epidemiology, University of Bristol, Bristol, United Kingdom
Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
The authors have declared that no competing interests exist.
GDS, SE, and ID designed the study. DAL and RH analyzed the data. DAL and SE enrolled patients. GDS, DAL, RH, NT, ID, and SE contributed to writing the paper.