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There are ongoing debates on issues relating to returning individual research results (IRRs) and incidental findings (IFs) generated by genetic research in population-based biobanks. To understand how to appropriately return genetic results from biobank studies, we surveyed preferences for returning IRRs and IFs among participants of the Tohoku Medical Megabank Project (TMM). We mailed a questionnaire to individuals enrolled in the TMM cohort study (Group 1; n=1031) and a group of Tohoku region residents (Group 2; n=2314). The respondents were required to be over 20 years of age. Nearly 90% of Group 1 participants and over 80% of Group 2 participants expressed a preference for receiving their genetic test results. Furthermore, over 60% of both groups preferred to receive their genetic results ‘from a genetic specialist.’ A logistic regression analysis revealed that engaging in ‘health-conscious behaviors’ (such as regular physical activity, having a healthy diet, intentionally reducing alcohol intake and/or smoking and so on) was significant, positively associated with preferring to receive their genetic test results (odds ratio=2.397 (Group 1) and 1.897 (Group 2)). Our findings provided useful information and predictors regarding the return of IRRs and IFs in a population-based biobank.

Several biobanks have begun returning genetic results to individuals, making the development of public genetic literacy an urgent task for their effective use. No research exists regarding the effects of genetic education on biobank participants, so we conducted genetics workshops with specialists, and surveyed differences in the participants' (n = 112) preferences to receive their own genetic information by disease categories and their genetic knowledge using questionnaires before and after the workshops. Almost 90% of our participants were over 60 years old, which was similar to our previous preference research. The preference to receive five of the six categories of genetic information (lifestyle diseases, pharmacogenetics, adult-onset non-clinically actionable diseases, non-clinically actionable multifactorial diseases, and all genetic information) was slightly but significantly decreased after the genetics workshop. More participants preferred to receive genetic results regarding lifestyle diseases, pharmacogenetics, and adult-onset clinically actionable diseases after the workshop, while less participants preferred to receive information regarding adult-onset non-clinically actionable diseases, non-clinically actionable multifactorial diseases, and all genetic information. Total genetic knowledge scores significantly increased after the workshop (before: 11.89, after: 13.30, p < 0.001). Our findings suggest that genetics workshops are useful to improve the genetic literacy of genome cohort participants.