This is an abstract that hasn’t been peer-reviewed… based on prescription data for an over-the-counter medication. This will be horribly inaccurate because it will miss all the folks who just buy the medication on their own and never have it documented.
These TriNetX studies are usually garbage because they’re entirely dependent on how accurate/up-to-date the medical record is.
Yes, this should have been a pure dose-response study among people with any history of filled melatonin scripts.
The comparison between the US and UK probably leads to two issues - US users use way too much melatonin and swamp heart disease signal, while UK patients prescribed melatonin probably have significant sleep derangement (consider how much effort it takes to get prescribed something for sleep - you need to schedule an appointment, convince your doctor, go to the pharmacy, etc)
These TriNetX studies are usually garbage because they’re entirely dependent on how accurate/up-to-date the medical record is.