To Your Health 

 A common excuse for wine lovers is that "a few glasses of wine are good for the heart". Well maybe for warming your heart but possibly not for preventing heart attacks.  

 A recent note in The Lancet (Vol 366, December 3, 2005, pages 1911-1912) suggests that earlier reports that light to moderate alcohol consumption can lower the risk of ischaemic heart disease were severely affected by confounders in non-randomized trials.  


 Some people believed that the early results were due to misclassification of former drinkers with cardio-vascular diseases ("CVD") as never-drinkers. This raised the CVD rate among the non-drinkers group. Another possible story is that the studies didn't properly control for confounders -- apparently some risk factors for CVD are more prevalent among non-drinkers, and the non-randmized studies didn't control well enough for those. But as the note points out, confounding could bias results both in favor or against a protective effect. Heavy drinking offers really good protection but those people don't live healtily lifes, and the health benefits would be obscured. 

 But don't fear, the  British Heart Foundation  says that low to moderate alcohol consumption probably doesn't do your heart any harm. For protection against CVD you should really quit smoking, do sports, and eat a balanced diet. Not quite as appealing as a good glass of wine, of course. 

 In any case, food for thought and a great 2-page piece for your next causal inference class. Cheers to that.