Recommended alcohol limits in many countries should be lowered to around 100g/week for men and women, according to an analysis of data from nearly 600,000 current drinkers in 19 countries, published in The Lancet.
100 g/week is equivalent to 5-6 standard UK glasses of wine or pints of beer per week or 12.5 units. Recommended limits in Italy, Portugal, and Spain are almost 50% higher than this, and in the USA, the upper limit for men is nearly double this (196 g/week or 11 glasses; 98 g/week for women). The findings from the study are in line with UK guidance which was recently lowered to 6 glasses a week for men and women.
The international team of researchers analyzed individual participant data taken from 83 studies in 19 high-income countries. The researchers also had access to data on participants’ age, sex, history of diabetes, smoking status and several other factors known to be related to cardiovascular disease. None of the participants had a known history of cardiovascular disease.
The study included data from 599,912 current drinkers. About 50% reported drinking more than 100 g/week, and 8.4% drank more than 350 g/week.
The study found an increase in all causes of death above 100 g/week alcohol consumed, supporting reductions of alcohol consumption limits in most existing guidelines across the globe.
In comparison to those who reported drinking less than 100 g/week, those who reported drinking 100-200 g/week, 200-350 g/week, or more than 350 g/week had an estimated lower life expectancy at age 40 years of approximately 6 months, 1–2 years, or 4–5 years, respectively.
Dr Angela Wood, the lead author, University of Cambridge, UK, says: “The key message of this research for public health is that, if you already drink alcohol, drinking less may help you live longer and lower your risk of several cardiovascular conditions.”
The researchers also looked at the association between alcohol consumption and different types of cardiovascular disease. Higher alcohol consumption was associated with a higher risk of stroke, heart failure, fatal hypertensive disease, and fatal aortic aneurysm. For these conditions, there were no clear risk thresholds below which lower alcohol consumption stopped being associated with lower disease risk. By contrast, increased alcohol consumption was associated with a somewhat lower risk of non-fatal heart attacks (“myocardial infarction”).
“Alcohol consumption is associated with a slightly lower risk of non-fatal heart attacks but this must be balanced against the higher risk associated with other serious – and potentially fatal – cardiovascular diseases,” explains Dr Wood.
The authors note that the different relationships between alcohol intake and various types of cardiovascular disease could be explained, at least in part, by the effect of alcohol consumption on elevated blood pressure and on factors related to elevated high-density lipoprotein cholesterol (HDL-C).
“Doctors and other healthcare professionals must heed this message and transmit it to their patients. This study has shown that drinking alcohol at levels which were believed to be safe is actually linked with lower life expectancy and several adverse health outcomes,” Dr Dan G Blazer, co-author, Duke University, USA.
The study focused on current drinkers to reduce the risk of bias caused by those who abstain from alcohol due to poor health. However, the authors note some limitations. Participants were recruited between 1964 and 2010 and each participant had a minimum of 12 months follow up. The study did not look at the effect of alcohol consumption over the life-course or account for people who may have reduced their consumption due to health complications. Finally, the study used self-reported alcohol consumption.
Professor Edoardo Casiglia, co-author, University of Padua, Italy, adds: “This study provides clear evidence to support lowering the recommended limits of alcohol consumption in many countries around the world.”