Drinking within recommended limits is highly prevalent in much of the world, and strong epidemiological associations exist between moderate alcohol consumption and reduced risk of several major chronic diseases, including coronary heart disease and diabetes with an elevated risk for breast cancer. In many cases, plausible biological mediators for these associations have been identified in randomised trials, but gold standard evidence that moderate drinking causes or prevents any chronic disease remains elusive and important concerns about available evidence have been raised. A review published in Alcoholism, Clinical and Experimental Research argues that a long-term trial of moderate drinking is no longer beyond consideration. The authors present potential lessons learned for such a trial and discuss key features to maximise its feasibility and value.
The review considers how clinical investigators have now successfully completed randomised trials of complex nutritional interventions in a variety of settings. For example, The Lyon Heart Study, where participants were educated to modify their diet to increase their intake of bread, green and root vegetables and fish and fruit and replace red meat with poultry and use a modified margarine and the PREDIMED trial , which required participants to adopt either a Mediterranean diet or a low fat diet. In addition, trials of alcohol consumption itself of up to 2 years duration study have been conducted by Israeli researchers among diabetic adults.
The authors suggest that previous trials of both alcohol consumption and other nutritional interventions offer specific, practical lessons for the design and conduct of a trial. They highlight that complex trials over many years can and should be carried out. Previous trials suggest that a longterm trial of alcohol consumption is feasible when those beverages trialled are those most culturally acceptable to the study population and where participants are asked to consume quantities not widely different from their normal pattern of drinking. Most of the successful trials have provided participants with more support than just advice. The authors also note that the successful long term dietary and alcohol trials have recruited individuals at an above average risk for the end point under investigation, which requires smaller sample sizes and might also recruit participants with a greater personal investment is the trial’s success.
Finally, existing clinical trials and epidemiological evidence provides useful insight into the end points that a clinical trial of moderate drinking might be best poised to tackle; High density lipoprotein cholesterol (HDL-C) has served as a marker for adherence in nearly all feeding studies of alcohol consumption and differences between abstainers and alcohol consumers become observable within a few week.
The authors argue that “Epidemiological studies also suggest that coronary heart disease and diabetes represent the most plausible improved end points for a trial of moderate drinking, with somewhat weaker evidence for ischemic (but not haemorrhagic stroke); a composite outcome of major cardiovascular events similar to that used in pharmaceutical trials appears sensible. Safety signals to be studied should include hypertension, injury and breast cancer.”
Source: Moderate alcohol consumption and chronic disease: The Case for a Long-Term Trial. Kenneth J. Mukamal, Catherine M. Clowry, Margaret M. Murray, Henk F.J. Hendriks, Eric B. Rimm, Kaycee M. Sink, Clement A. Adebamowo, Lars O. Dragsted, P. Scott Lapinski, Mariana Lazo, and John H. Krystal. Alcoholism: Clinical and Experimental Research, published early online 30 September 2016.