Another point about alcohol consumption is that the studies showing a slight benefit include former alcoholics/heavy drinkers in the abstinence group - often a significant proportion of said group. Taking that into account effectively erases all proclaimed benefits of even slight alcohol consumption (here's recent example: https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003819).
Interesting stuff!
Another point about alcohol consumption is that the studies showing a slight benefit include former alcoholics/heavy drinkers in the abstinence group - often a significant proportion of said group. Taking that into account effectively erases all proclaimed benefits of even slight alcohol consumption (here's recent example: https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003819).
That's a great point! Striating populations that way would definitely skew the results!