Study Profile of the Iwate PGS Assessment and Risk Communication (PARC) Study.

Background: The potential impacts of polygenic scores (PGS) on health-behavior changes are not fully understood. The Iwate PGS Assessment and Risk Communication Study aims to investigate the effects of reporting PGS-based risk for ischemic stroke on health behaviors.

Methods: Participants wishing to know their PGS-based ischemic stroke risk were recruited from health checkup venues for workers in Iwate Prefecture in 2023. Health checkup data, biospecimens, and questionnaire responses were collected for biochemical testing, genotyping, and storage in the Tohoku Medical Megabank integrated biobank. The risk was calculated using an integrative PGS model for East Asians. Participants were randomly assigned to two groups, and one group received their risk report as the intervention group. The impacts of the risk notification will be investigated in follow-up surveys.

Results: Of 3,599 workers, 2,088 participated in the study (consent rate, 58.0%). The demographic profile of the eligible 2,083 participants was as follows: 80.7% males, and dominance of participants aged 18-29 years (25.2%), in their 30's (25.3%), and in their 40's (24.7%). Two hundred participants (9.7%) had a risk of 1.0 as the reference; 57 (2.7%), 927 (44.7%), and 888 (42.9%) participants had 2.1-3.4-, 1.4-1.9-, and <1.0-fold that risk, respectively.

Conclusion: We collected health information and biospecimens from over 2,000 workers, and disclosed the PGS-based ischemic stroke risk. Behavioral effects will be evaluated 1 year after disclosure, with follow-up until 2030. As Japan's first large-scale PGS risk communication study, it will provide initial insights for implementing PGS in personalized preventive medicine.