September 17, 2015

expert reaction to study on alcohol consumption, cardiovascular disease, cancer, and mortality

Depending on extent, alcohol consumption has been previously linked with both positive and negative health outcomes. Publishing in The Lancet journal a group of researchers have investigated the effect that alcohol has on populations with differing income levels, and they report that intake was associated with lower levels of heart attacks, and higher levels of certain cancers and injury, with high intake being associated with higher mortality.

Dr Gavin Sandercock, Reader in Clinical Physiology (Cardiology), University of Essex, said:

“Several studies and reviews have shown that moderate alcohol intake is associated with lower mortality so these findings are no surprise. The figure for reduced myocardial infarction (MI) of 24% in the press release is not mentioned in the actual paper itself. In isolation, this figure should be interpreted cautiously as the authors have quoted a relative risk figure to indicate reduction for MI – which is indeed 24%- but the absolute risk of MI is quite low in the populations studied which makes it hard to generalise from this number.

“In statistical terms, 0.82% of low alcohol intake drinkers had an MI, 0.96% of moderate drinkers did, and for high intake drinkers the figure was 1.23%. The difference in absolute risk of MI between the high and low intake drinkers is 0.41 percentage points, so the risk of an MI for An adult with high alcohol intake individual is 0.41% higher than that for someone with low alcohol intake. Based on these figures, there would be 8 MIs in every 1000 low intake drinkers, 10 MIs in every 1000 moderate drinkers, and 12 MIs in every 1000 high intake drinkers.

“Even when looking at ‘high episodic’ drinking (binge drinking) using the same method, we would expect 10 MIs per 1000 heavy drinkers compared with 7 MIs in non-heavy drinkers. These are not big differences in absolute risk. Furthermore, the figure quoted (24%) is unadjusted, so when everything is taken into account there seems to be no difference in MI risk between different alcohol intake drinkers.

“Furthermore, the press release says ‘high alcohol intake and heavy episodic drinking were both associated with significant increases in risk of overall mortality’, but it must be remembered that while the relative risk of dying is higher in drinkers this is in comparison with people who have never drunk alcohol in their lives. This is a very small proportion of the British population, only about 1 in 5 are teetotal and the number of lifelong abstainers is even smaller. ”

‘Alcohol consumption and cardiovascular disease, cancer, injury, admission to hospital, and mortality: a prospective cohort study’ by Smyth et al. published in The Lancet on Thursday 17th September. 

Declared interests

Dr Gavin Sandercock: No conflicts of interest