1 Violence and Society Centre, City, University of London, London EC1V 0HB, UK.
2 Department of Biostatistics and Health Informatics, King's College London, London, UK.
3 School of Health Sciences, City, University of London, London EC1V 0HB, UK.
4 Population Data Science, Swansea University, Swansea, UK.
5 Violence and Society Centre, City, University of London, London EC1V 0HB, UK; National Centre for Social Research, London, UK. Electronic address: sally.mcmanus@city.ac.uk.