It's not any new research. Just a simple conclusion from the entirety of research in this field. All research shows that there's no safe dose of alcohol. That starting to drink never improved anyone's health. So if there's correlation between health and moderate use any causation that might be there can't go from alcohol to improved health. So it most likely goes the other way around. Or both things are a result of other factor. For example affluence. It is known that more affluent people drink more and at the same time more affluent people have better health. "moderately" is just roughly the level where damage from alcohol balances out the health surplus of whatever caused them to drink more.
It's not any new research. Just a simple conclusion from the entirety of research in this field. All research shows that there's no safe dose of alcohol. That starting to drink never improved anyone's health. So if there's correlation between health and moderate use any causation that might be there can't go from alcohol to improved health. So it most likely goes the other way around. Or both things are a result of other factor. For example affluence. It is known that more affluent people drink more and at the same time more affluent people have better health. "moderately" is just roughly the level where damage from alcohol balances out the health surplus of whatever caused them to drink more.