Screening for Parkinson’s disease using prodromal symptoms was as accurate as current screening tests for certain cancers.

The first symptoms of Parkinson’s disease have been referred to by many experts as prodromal. In this study from a cohort of 51,529 US-based male health professionals who filled out biannual questionnaires, the authors assessed and then reassessed 6108 men using two composite measures. The first was co-occurrence of constipation, probable rapid eye movement sleep behaviour disorder (pRBD) and hyposmia. The second was probability of prodromal Parkinson’s disease calculated from the Movement Disorders Society research criteria.

During an average follow up of 3.4 years, 103 men had a new diagnosis of Parkinson’s disease. Those with constipation, pRBD and hyposmia had a 23 times increased risk for Parkinson’s disease diagnosis compared to those with none of these symptoms. Those with any one of these symptoms had a 2.5 times increased risk (with constipation) to 6.6 times increased risk (with hyposmia). The two composite measures had comparable predictive values. The predictive values of the symptoms for Parkinson’s disease, individually and combined, were comparable to those of screening tests for colorectal cancer (the faecal immunochemical test) and prostate cancer (prostate specific antigen testing). 

Comment: General practitioners should be asking three questions, especially in ageing populations. Are you regularly constipated, are you acting out your dreams and have you lost your sense of smell? The presence and particularly the combination of these symptoms will increase the risk for a near-term diagnosis of Parkinson’s disease. The comparable efficacy of this screening to those of cancer screenings is powerful support for using this tool.

Michael S. Okun, MD, Adelaide Lackner Professor and Chair of Neurology and Executive Director, Fixel Institute for Neurological Diseases, University of Florida McKnight Brain Institute, Gainesville, USA.

Flores-Torres MH, et al. Identifying individuals in the prodromal phase of Parkinson’s disease: a prospective cohort study. Ann Neurol 2025; 97: 720-729.

This summary is taken from the following Journal Watch title: Neurology.