Hundreds of observational, epidemiological studies have found that moderate alcohol intake is associated with a lower risk of a range of health outcomes compared to alcohol abstention, but that risk increases with heavy drinking (a distribution commonly known as a ‘U-shaped’ or ‘J-shaped’ curve) [1]. Many researchers, clinicians and the lay public now accept as common knowledge that moderate drinking is beneficial to one's health [2], and the association is hypothesized to be due to biological effects on several systems, including reduced blood pressure, increased blood lipoproteins and oxidation of low-density lipoprotein (LDL) cholesterol, among other pathways [3, 4].
There are, however, methodological issues and data inconsistencies regarding the relation between alcohol intake and health that require further investigation before the case is closed on moderate drinking. Resolving these outstanding issues and inconsistencies is of substantial public health importance: many individuals are now consuming alcohol, typically red wine, as a prescriptive for better health. If the relation between moderate alcohol consumption and health is more artifactual than causal, then public health recommendations will need to be reconsidered.
The first issue raised by Dawson et al. [5], and documented in other studies as well, is the ‘sick quitter’ effect. Dawson et al. document that individuals with incident cardiovascular disease and those rating health as good/fair/poor (versus very good or excellent) at age 55+ were more likely to stop drinking, as well as individuals with liver disease at ages 18–34. Thus, when alcohol intake is measured at a single time-point, non-drinkers will constitute both former drinkers who quit due to poor health and life-time abstainers. Separating former drinkers from life-time abstainers in studies of the effects of alcohol consumption on mortality is thus essential. Indeed, a recent analysis that did this showed that the J-shaped curve disappeared after taking into account former drinkers who quit due to poor health and that the association between alcohol consumption and mortality changed to a simple monotonic function: greater levels of alcohol consumption are associated with higher mortality [6]. > > > > Read More
The first issue raised by Dawson et al. [5], and documented in other studies as well, is the ‘sick quitter’ effect. Dawson et al. document that individuals with incident cardiovascular disease and those rating health as good/fair/poor (versus very good or excellent) at age 55+ were more likely to stop drinking, as well as individuals with liver disease at ages 18–34. Thus, when alcohol intake is measured at a single time-point, non-drinkers will constitute both former drinkers who quit due to poor health and life-time abstainers. Separating former drinkers from life-time abstainers in studies of the effects of alcohol consumption on mortality is thus essential. Indeed, a recent analysis that did this showed that the J-shaped curve disappeared after taking into account former drinkers who quit due to poor health and that the association between alcohol consumption and mortality changed to a simple monotonic function: greater levels of alcohol consumption are associated with higher mortality [6]. > > > > Read More
