World Health Organization (WHO) - Brain Health Unit, World Health Organization (WHO) - Brain Health Unit, University of Florida - Department of Neurology, University of Southampton - Department of Gerontology, University of Rochester Medical Center, Radboud University Nijmegen - Donders Institute for Brain, Cognition and Behaviour, Parkinson’s Disease and Movement Disorder Society, Chulalongkorn University - Chulalongkorn Centre of Excellence for Parkinson’s Disease & Related Disorders, World Health Organization (WHO) - Chemical Safety and Health Unit, University Teaching Hospital (UTH), Lusaka, World Health Organization (WHO) - Brain Health Unit, Edmond J. Safra Foundation, University of Burgos - Hospital Universitario de Burgos, Hofstra Northwell - Donald and Barbara Zucker School of Medicine, The Michael J. Fox Foundation, University of Liverpool - Department of Primary Care and Mental Health, The University of Sydney - Movement Disorders Unit, Favaloro Foundation University Hospital - Institute of Neuroscience, Person with Parkinsons; PD Avengers, Neurological Health Charities Canada, Qatar University - Department of Physiotherapy, Charité - Universitätsmedizin Berlin - Movement Disorder and Neuromodulation Unit, Malaysian Parkinson’s Disease Association, University of Malaya (UM) - Division of Neurology, Parkinson Canada, Parkinson Canada, University of Oxford, Johns Hopkins University - Department of Neurology, Cornell University - Weill Cornell Parkinson’s Disease and Movement Disorders Institute, University of Lagos - College of Medicine, National Institute of Mental Health and Neurosciences (NIMHANS), Columbia University - Irving Medical Center, Ain Shams University - Department of Neurology, The Michael J. Fox Foundation, The Michael J. Fox Foundation, The Michael J. Fox Foundation, Charité - Universitätsmedizin Berlin - Department of Gynaecology, Northumbria Healthcare NHS Foundation Trust and World Health Organization (WHO) - Brain Health Unit

University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Liverpool - Department of Primary Care and Mental Health, University College London - Division of Psychiatry, University of Southampton - Primary Care and Population Science, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Southampton - Southampton Clinical Trials Unit, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Leicester - Leicester Clinical Trials Unit, London School of Hygiene & Tropical Medicine - Faculty of Public Health and Policy, University of Liverpool - Department of Primary Care and Mental Health, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Liverpool - Department of Primary Care and Mental Health, University of Liverpool - Department of Primary Care and Mental Health, University of Liverpool - Department of Primary Care and Mental Health, University of Liverpool - Department of Primary Care and Mental Health, University of Liverpool - Department of Primary Care and Mental Health, University College London - Division of Psychiatry, University College London - Division of Psychiatry, University College London - Division of Psychiatry, University College London - Division of Psychiatry, University College London - Division of Psychiatry, University of Southampton - School of Primary Care, Population Sciences and Medical Education, University of Southampton - School of Primary Care, Population Sciences and Medical Education and Queen Mary University of London - Wolfson Institute of Population Health