So bringing things back on topic, the challenge that we have with DecodeME is how to engage with those people and a lot of thought and effort is going into that.
Maybe it's not possible to directly engage with many of them.
[Edit: Apologies -- just realized that I'm being bit repetitive, but there will be a new suggestion in the post below this one.]
I think many of them won't engage with social media networks on chronic illness either.
So what's needed is big public awareness of the study outside our networks.
Just some thoughts on top off my head how that could be achieved:
1) placing the study as often as possible in public media (UK and worldwide)
2) announcement in newspapers, including online announcements (UK) -- perhaps involve online marketing experts (social media)
3) leaflets and posters in public transport, drug stores, pharmacies etc. (UK)
4) leaflets and posters in clinics and doctors' offices (UK)
5) snow ball principle that doesn't rely on social media networks and algorithms (UK and worldwide)
Ad 2)-4) If public announcements/ posters are too expensive, perhaps consider additional crowdfunding?