A bit more profiling would be helpful
As noted, information as to why people stopped drinking or didn't start would be good.
Also any chronic health conditions, level of obesity, level of exercise.
Intrigued because the traditional "beer belly" is associated with all sorts of medical issues.
I may be completely wrong but I don't think you get a wine belly (apart from the associated munchies).
Perhaps the Mediterranean Diet isn't about what you eat but what you drink.
A diet of strong beer is bad for you?