[mike_esspe]

Looks like confounding factors are the reason.

http://www.ncbi.nlm.nih.gov/pubmed/22152665

CONCLUSIONS: Among older adults who are moderate drinkers, the apparent unique effects of wine on longevity may be explained by confounding factors correlated with wine consumption.

[conroe64]

I don't understand what you are trying to show with this study. It compares moderate drinkers among themselves according to the type of alcohol consumed. It doesn't compare drinkers vs non drinkers