Previous studies indicating that alcohol consumption may lessen the pain and inconvenience of rheumatoid arthritis (RA) are victims of flawed interpretation, the authors of a new paper assert.

Writing in the journal Arthritis Care & Research, researchers led by Joshua Baker of the University of Pennsylvania, US, examined the records of 16,762 RA patients and concluded that any link between alcohol and disease management was more illusory than real.

Although results are by no means unanimous, in the past few years there have been enough studies published indicating that moderate boozing makes life easier for RA sufferers for the idea to have taken root as common wisdom.

Looking at the progression of RA over time, and the influence of factors such as other illnesses, Baker and colleagues conclude that the apparent positive link between alcohol and quality of life can be explained as the result of “reverse causation” – that is, previous studies have confused cause with effect.

Analysing a total of 121,280 observations made within the cohort, the researchers found that as RA became more severe patients were likely to give up, rather than maintain or increase, alcohol consumption.

Similarly, a host of other factors also meant some RA sufferers were more likely to give up the booze, while others were unlikely to start.

“Greater discontinuation and less initiation were observed with greater disease activity, older age, female sex, non-white race, obesity, greater comorbidity, low quality of life, low educational level, low income, and work disability,” they write.

In addition, they note, alcohol consumption is often not a static matter, but changes according to time, age and circumstance. A problem in analysis arises, therefore, if initial estimates are not updated.

“If severely affected individuals are more likely to discontinue alcohol use over time, studies that consider alcohol use at a fixed point in time, perhaps at enrolment in a disease registry, are likely to identify a protective association of alcohol use when one, in fact, does not exist,” the researchers write.

The new analysis paints a very different picture to the one often presented as beyond question.

Rather than turn to alcohol for therapeutic relief when RA becomes severe, the study found that “higher disease activity is associated with subsequent discontinuation of alcohol use and a lower likelihood of initiating use”.

“In this study,” the authors conclude, “active use and recent changes in alcohol use were not found to be associated with disease activity or death when considering confounding factors, suggesting no clear benefit of moderate alcohol consumption in RA.”

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