Pinpointing the health effects of alcohol

The possible health benefits of alcohol consumed within recommended limits continue to cause extraordinary controversy, chiefly because of the lack of experimental evidence that would put this question to rest. This uncertainty has fueled investigational ingenuity, including challenging animal models,1 dynamic alcohol trajectories,2 prolonged feeding studies,3 and genetic studies.4 5 But this creativity has often come at the expense of generalizability or precision. In a linked article, Dukes and colleagues retrace a few decades of footsteps to explore another novel approach.6

For decades, ecological designs have been used to compare alcohol consumption at the population level and various indicators of national cardiovascular disease burden (commonly age specific cardiovascular death rates). For example, in a 1980 review, Laporte and colleagues found a partial correlation coefficient of −0.65 across 20 developed nations between death rates from coronary heart disease among middle aged men and national rates of alcohol consumption.7

Ecological analyses have both advantages and disadvantages. Among the advantages, confounding by certain individual level …