Commentary on Britton et al. (2010):The dangers of declining drink add_2895 646..648 The real significance of the Britton et al. [1] paper is overlooked by the authors themselves. Alcohol intake varies in the same individuals over time, declining with increasing age in many countries [2][3][4][5][6][7]. This decline has been shown to occur among those individuals most vulnerable to morbidity and mortality [8][9][10]. People most likely to be stable in their drinking-the light or moderate drinkers-tend to have the most favourable health characteristics [11,12]. Britton et al. acknowledge these findings by stating that it is well established that the nondrinking group often includes former drinkers who terminated consumption due to ill health.The Britton et al. results are not surprising, in that they show a 'drift' down in consumption after the middle years of life among those who have been 'heavier' drinkers at one time or another. An understanding of this 'drift' requires multiple measurements associated with health changes over time. The authors might have contributed substantially to understanding whether it is the declining drink, the illness/medication or the interactions of these that predict premature mortality/morbidity.Britton et al. provide but four characteristics of group variability (smoking, age, employment grade and alcohol consumption in the last week). Unfortunately, the authors do not supply the characteristics relating to health status, serious disease and medication use that might account not only for the decline in the drinking, but also for mortality/morbidity. If these characteristics are not factored into the analysis, we have no understanding of what is actually driving the elevated riskthe drinking, the onset of illness or both.Despite this major limitation, this paper should be welcomed because cohort studies associating alcohol use with disease outcomes have lagged far behind the remainder of the alcohol field, the latter taking into account variation in drinking behaviour. In recent years greater attention has been paid to these matters by cohort studies, but they are few (e.g. [13][14][15]). They illustrate that drinking behaviour is complex and may be implicated with respect to disease incidence and, in fact, may be critical-but only in part-to understanding how drinking might affect outcome.Previously, alcohol studies have put great emphasis on differentiating between these patterns, recognizing that they had profound implications for social problems, accidents and injuries. Knupfer's 1989 [16] attempt to classify drinkers into, among other groups, a variety of 'heavy' drinkers found that when the bar was set low, the association between 'heavy' drinking and frequent drunkenness and serious problems was missed. This required the combination of 10 general population crosssectional data sets. Like most studies, Britton et al. lack an adequate sample size. As anyone performing these studies will testify, the choice of analytical strategy is difficult, the analysts fast run out of...