Population Genetic Screening in Adults: Implementation and Health Equity Considerations

Abstract

Population genetic screening among adults has been suggested as a strategy to identify people at risk for adult-onset diseases or disorders of cancer and high lipids who would benefit from early preventive intervention, but who are often missed under current genetic testing guidelines. Considering implementation challenges and health equity in population genetic screening programs is essential to ensure that screening leads to health benefits and existing health disparities are not perpetuated or widened. This dissertation examines disparities in, and barriers to, screening enrollment and subsequent preventive services, and explores health equity considerations during different population genetic screening stages. In Chapter 1, we briefly discuss motivations for population genetic screening and examples of prior screening programs. In Chapter 2, we assess enrollment in and attitudes toward population genetic screening using data from a population genetic screening research study conducted at the University of Washington Medical Center. We found that enrollment varied by race and ethnicity and was low overall (7%), with large dropout seen during initial screening recruitment. Possible disease prevention was a shared motivator for screening among those who enrolled. We also observed three themes related to declining screening: benefits do not outweigh risks, don’t want to know, and challenges with study logistics. Our results suggest that population genetic screening programs may replicate historical patterns of differential uptake of genetic services. Future programs focused on reducing logistical obstacles surrounding screening may limit these differences. In Chapter 3, we explored psychosocial impacts of learning about genetic screening results, pursuit of follow-up care, and opinions about screening among people receiving positive screening results from the population genetic screening research study conducted at the University of Washington Medical Center. We found that psychosocial impacts from screening results were limited and that participant views of result utility influenced clinical confirmation and follow-up care decision-making. After result return, many potential barriers were also present when pursuing clinical confirmation and prevention. As such, future programs would benefit from providing support not just during the initial screening process, but later in prevention stages. In Chapter 4, we identified implementation science frameworks that center health equity and assessed their applicability to population genetic screening programs. We found that frameworks provided broad guidance, including focusing on historically underserved populations, forming community partnerships, and adapting interventions to local context. However, guidance was limited for follow-up care and cascade screening stages of screening programs. Through our analysis, we created a list of health equity considerations and outcomes for population genetic screening. These considerations can be used to improve the equitable design, implementation, and evaluation of future programs. Overall, results from this dissertation provide insight into challenges that may emerge during population genetic screening related to ensuring disease prevention and promoting health equity. Without careful consideration of such challenges, benefits from population genetic screening may be inequitably distributed.