toblish did a good job for (1). For (3) there are a number of related effects:
- black patients are simply poorly treated by white doctors. One notorious myth (still taught in some medical schools) is that black people have a higher pain tolerance than Whitt people and are less in need of painkillers. This is an extremely serious problem:
> “Black people’s nerve endings are less sensitive than white people’s.” “Black people’s skin is thicker than white people’s.” “Black people’s blood coagulates more quickly than white people’s.”
> These disturbing beliefs are not long-forgotten 19th-century relics. They are notions harbored by far too many medical students and residents as recently as 2016. In fact, half of trainees surveyed held one or more such false beliefs, according to a study published in the Proceedings of the National Academies of Science. I find it shocking that 40% of first- and second-year medical students endorsed the belief that “black people’s skin is thicker than white people’s.”
(source: https://www.aamc.org/news-insights/how-we-fail-black-patient... )
- white racism itself is a constant source of low-level stress for many black Americans, which is plausibly (but not provably) implicated in numerous health disparities. It is obviously quite difficult to run an ethical controlled experiment here, but I think it’s quite believable that the overall impact of racism on anxiety (even if it’s somewhat minor for many individuals) can add up to a notable disparity in sleep hygiene.
I am having trouble finding specific sources because I am on my phone. I am also a mathematician, not a doctor or a sociologist. You could Google Scholar phrase like “medical racism” or “health impacts of discrimination” and do more reading.