Subjects at risk of Parkinson’s disease in health checkup examinees: cross-sectional analysis of baseline data of the NaT-PROBE study

Introduction: The present study aimed to survey the prevalence of prodromal symptoms of Parkinson’s disease (PD) in Japanese health checkup examinees, for identifying at-risk subjects. Methods: We conducted a questionnaire survey of annual health checkup examinees without neurological symptoms using the following self-reported questionnaires: Japanese version of the Scale for Outcomes in Parkinson’s disease for Autonomic Symptoms (SCOPA-AUT); Self-administered Odor Question (SAOQ); REM Sleep Behavior Disorder Screening Scale (RBDSQ); Beck Depression Inventory-Second Edition (BDI-II); Epworth Sleepiness Scale (ESS); and Physical Activity Scale for the Elderly (PASE). The presence of prodromal symptoms was determined using the 90th percentile threshold of each questionnaire. Subjects ≥ 50 years of age with ≥ 2 core prodromal symptoms (dysautonomia, hyposmia, and RBD), were classified as at risk. Results: Between March 2017 and March 2018, 4,953 participants sufficiently answered the questionnaires. Among 2,726 subjects ≥ 50 years of age, 155 were classified as at risk. These subjects had worse values of BDI-II (12.0 ± 8.3 vs. 4.4 ± 3.8, p < 0.001) and ESS (9.6 ± 5.0 vs. 6.3 ± 3.2, p < 0.001), in addition to SCOPA-AUT, SAOQ, and RBDSQ. Male at-risk subjects showed lower values of hemoglobin (14.8 ± 1.3 vs. 15.0 ± 1.1, p = 0.032) and low density lipoprotein cholesterol (114.5 ± 30.3 vs. 123.0 ± 28.9, p = 0.004) than the examinees reporting no prodromal symptoms. Conclusion: Approximately 6% of the population aged 50 years or older was at risk for PD. Male at-risk subjects had mild hematological and metabolic changes relevant to PD.