Supplementary Material for: Understanding Factors Associated with Uptake of BRCA1/2Genetic Testingamong Orthodox Jewish Women in the USA Using a Mixed-Methods Approach

Background/Aims: Ashkenazi Jews have a 1:40 prevalence of BRCA1/2 mutations. Orthodox Jews are an understudied population with unique cultural and religious factors that may influence BRCA1/2 genetic testing uptake. Methods: Using a mixed-methods approach, we conducted a cross-sectional survey and focus groups among Orthodox Jewish women in New York/New Jersey to explore factors affecting decision-making about BRCA1/2 genetic testing. Results: Among 321 evaluable survey participants, the median age was 47 years (range, 25–82); 56% were Modern Orthodox and 44% Yeshivish/Chassidish/other; 84% were married; 7% had a personal history of breast or ovarian cancer. Nearly 20% of the women had undergone BRCA1/2genetic testing. Predictors of genetic testing uptake included being Modern Orthodox (odds ratio [OR] = 2.31), married (OR = 3.49), and having a personal or family history of breast or ovarian cancer (OR = 9.74). Focus group participants (n = 31) confirmed the importance of rabbinic consultation in medical decision-making and revealed that stigma was a prominent factor in decisions about BRCA1/2 testing due to its potential impact on marriageability. Conclusion: In order to increase the uptake of BRCA1/2 genetic testing among the Orthodox Jewish population, it is crucial to understand religious and cultural factors, such as stigma and effect on marriageability, and engage religious leaders in raising awareness within the community.