Even Light to Moderate Drinking Increases Heart Disease Risk
Contradicting previous research, a large study published in the British Medical Journal has found that even small amounts of alcohol can increase the risk of coronary heart disease.
This of course differs from findings from previous (observational) studies indicating that while moderate to heavy drinking increased heart disease risk, light to moderate alcohol consumption reduced the risk of heart disease.
This new study – a large randomized study that utilized a genetic marker to confirm alcohol intake – finds that no amount of alcohol reduces the risk of heart disease – and any regular consumption increases the risk.
The researchers determined this result by examining patient data from 261,991 European adults, derived from 56 studies. The researchers stratified alcohol consumption between non-drinkers, light drinkers, moderate drinkers and heavy drinkers.
They found that all of the categories except for the non-drinkers had an increased risk of heart disease. This increase ranged from light to heavy drinkers.
The researchers confirmed this result by measuring the effects with a genetic marker shown to indicate the extent of alcohol consumption – the rs1229984 gene variant. This gene variant indicates either non-drinking or a weekly alcohol consumption of less than 10 ml of alcohol per week – a very small amount. The gene variant also indicates fewer binge drinking events.
In other words, having this variant will equate to practically no alcohol consumption.
The researchers found those with this gene variant had a lower risk of heart disease as well as lower blood pressure, lower inflammation.
Those with the lower drinking consumption – those with the gene variant – had a significantly reduced risk of stroke, had 17% lower body mass index, 30% lower waist circumference, had lower systolic blood pressure and lower levels of inflammation measured by interleukin-6 levels.
The researchers concluded:
“These data show that individuals of European descent with a genetic predisposition to consume less alcohol had a reduced risk of coronary heart disease and ischaemic stroke, and lower levels of several established and emerging risk factors for cardiovascular disease. These findings suggest that reductions of alcohol consumption, even for light to moderate drinkers, may be beneficial for cardiovascular health. Our results therefore challenge the concept of a cardioprotective effect associated with light to moderate alcohol consumption reported in observational studies and suggest that this effect may have been due to residual confounding or selection bias.”
Why is this finding more reliable than the previous research?
Because this gene variant is specific to drinking alcohol, the finding is considered to have greater accuracy than observational studies, which lack in their randomness and control.
In other words, these studies rely upon people’s calculation of their own drinking habits, which can often be different from the actual amounts consumed. Also, such studies cannot eliminate (or control) the effects of other activities such as exercise. In other words, people who are light drinkers also often tend to exercise more – as have been found in some other research. That has produced an assumption this study proves was inaccurate.
And while one might suggest that further research is needed, the researchers did compile the evidence from nearly 60 different studies involving almost 300,000 people.
Note the study isn’t suggesting that it doesn’t matter whether one drinks light or heavy amounts of alcohol – their risk will be the same.
The study did indicate dose dependency – meaning that light drinking increases heart disease risk less than heavy drinking.
But regularly drinking small amounts does not help prevent heart disease as was supposed from the previous observational studies.
Holmes MV, et al. Association between alcohol and cardiovascular disease: Mendelian randomisation analysis based on individual participant data. BMJ. 2014 Jul 10;349:g4164. doi: 10.1136/bmj.g4164.