I resonated with your work being at the "zeroth" stage. Even at its early stages, it's great that you're thinking about how the new test you are working on can be validated in an ethnically diverse population in the hopes of having generalizable applications. I think a good starting point would be to recruit participants in clinics or hospitals that cater to underserved populations. The follow-up process of these people should take into account the enablers and barriers that make it difficult to attend follow-up visits, log blood pressure information, etc. This is definitely a very difficult field to navigate, but I think you are doing a great job of conceptualizing how social determinants fit into it.