A 2010 study confirmed the beneficial effect of moderate alcohol consumption on mortality. Subjects were grouped into abstainers, light, moderate, and heavy drinkers. The order of mortality rates from lowest to highest were moderate, light, heavy, and abstainers. The increased risk for abstainers was twice the mortality rate as for moderate drinkers. This study specifically sought to control for confounding factors including the problem of ex-drinkers considered as non-drinkers. According to another study, drinkers with heavy drinking occasions (six or more drinks at a time) have a 57% higher all-cause mortality than drinkers without heavy drinking occasions.