Wednesday July 28 2010
Rheumatoid arthritis can be painful and debilitating
“Drinking alcohol can reduce the severity of the symptoms of rheumatoid arthritis,” according to the Daily Mail. The newspaper said that non-drinkers “are four times more likely to develop rheumatoid arthritis than those who drink alcohol on more than ten days a month”.
The research behind this news used a questionnaire to ask people with rheumatoid arthritis and a group of healthy volunteers about how often they drank alcoholic drinks. The results showed that frequency of alcohol consumption was associated with both the risk of developing rheumatoid arthritis and the severity of the disease.
However, this research has many limitations, including the fact that it did not examine the quantities of alcohol actually consumed or follow drinking habits over time. The research may initiate another line of investigation but, on its own, the evidence is not strong enough to inform us whether or not alcohol helps rheumatoid arthritis. Combining certain arthritis medications with alcohol may be dangerous. People with rheumatoid arthritis should speak to a doctor or pharmacist for specific advice on this matter.
Where did the story come from?
The study was carried out by researchers from the University of Sheffield and the Sheffield Teaching Hospitals NHS Foundation Trust. It was funded by the Arthritis Research Campaign and published in the peer-reviewed medical journal Rheumatology.
The Daily Telegraph pointed out that the study had not looked at the amount of alcohol the participants drank and the Daily Mail said that no details of the type of alcohol were given, which were both good points to make.
The Sun said that “the only treatment is a course of painkillers”. This is not true. Patients can be given a variety of other treatments that reduce the inflammation associated with this disease.
What kind of research was this?
This was a case control study comparing a group of people with rheumatoid arthritis with a control group of healthy people. It looked at whether the frequency of alcohol consumption had any effect on the likelihood of developing rheumatoid arthritis or the severity of the disease. The researchers also looked at the association between drinking alcohol and the severity of disease in a separate cross-sectional analysis.
The researchers were interested in this potential relationship as they say that there is evidence from a Scandinavian case control study that suggests that there was a ‘dose-dependent effect’ of alcohol on the risk of developing rheumatoid arthritis (meaning that the more alcohol a person drank, the lower their risk of arthritis). They wanted to follow up this potential association using a UK cohort. They additionally wanted to look at whether alcohol affects disease severity, as they say there have been no investigations into this.
As this was a case control study it cannot determine whether alcohol causes a particular effect. Studies of this type can only find associations between factors, which then would require further follow up.
What did the research involve?
The study recruited 873 white Caucasian patients with rheumatoid arthritis and 1,004 healthy controls from the Royal Hallamshire Hospital in Sheffield between 1999 and 2006.
The patients had experienced rheumatoid arthritis for at least three years. The patients and controls were asked about their smoking and alcohol exposure in a self-completed questionnaire that was given to patients at the start of the study. Participants were asked to define their previous drinking behaviour as ‘never’ or ‘ever to regular’ and record the number of days on which they had consumed at least one alcoholic drink over the previous month. They were categorised according to the number of recent days on which they drank. The categories were: ‘no alcohol’, ‘1-5 days’, ‘6-10 days’ and ‘more than 10 days’. Smoking status was also recorded, with patients categorised either as ‘current smoker’, ‘previous smoker’ or ‘never smoker’.
The researchers say that there are different subsets of rheumatoid arthritis. Patients with the ‘CCP-positive’ form of the disease have CCP antibodies in their blood. The researchers measured the amounts of CCP antibodies in the patients and in 100 of the controls. The researchers also accessed the medical records of the patients to examine information about how many joints were affected, how much pain the patients were in and the level of disability the patients experienced due to their condition.
In rheumatoid arthritis the patient may experience damage to the bone and cartilage. A radiologist assessed radiographs of the hands and feet of the patients to give a score of joint damage. A sample of 10% of the radiographs was checked by another assessor to verify that the scoring was consistent.
The researchers used an established statistical method called ‘logistic regression’ to assess the effect of alcohol on rheumatoid arthritis. In their calculations they adjusted their model to account for age, gender and smoking status. They used this model to assess whether the severity of rheumatoid arthritis was different depending on how much alcohol a person drank.
What were the basic results?
They found that the patients in the rheumatoid arthritis group were older on average and more likely to smoke than the controls. There was also a higher proportion of females in the arthritis group than in the control group. The controls were also more likely to drink, with only 10.9% of controls reporting no regular alcohol consumption compared with 36.7% of the arthritis patients. Likewise, a greater number of controls reported that they drank on more than 10 days per month (30%) compared with 16% of the patients.
The researchers found that there was no difference in the alcohol consumption in patients with the CCP-positive form of the disease compared with other rheumatoid arthritis patients. However, they did find that there was a difference in the alcohol consumption of the patients depending on the medication they were taking. For example, patients taking the anti-rheumatoid drug methotrexate (alone or with other anti-rheumatoid arthritis drugs called DMARDs) were less likely to consume alcohol frequently than patients taking other drugs for the condition.
When they compared the risk of developing rheumatoid arthritis by looking at the alcohol consumption in the control group and rheumatoid arthritis group, non-regular drinkers had a higher risk of developing rheumatoid arthritis compared with regular drinkers (Odds ratio [OR] 2.31, 95% confidence interval CI, 1.73 to 3.07). They also found that, compared with the most frequent drinkers, never-drinkers had an increased risk of developing rheumatoid arthritis (OR 4.17, 95% CI 3.01 to 5.77).
Increasing frequency of alcohol consumption was associated with decreased rheumatoid arthritis severity. This was the case for all of the measures of rheumatoid arthritis, and the association still existed after the researchers had taken into account the gender of the patients and whether the patients were CCP-positive or not.
The researchers had found that how regularly people on certain types of anti-rheumatoid arthritis drugs drank alcohol differed depending on the type of medication they took. People taking methotrexate (with or without DMARDs) drank less frequently. They looked at people’s history of alcohol consumption (never-drinkers or ever to regular drinkers) in groups of patients taking methotrexate and found that ever-drinkers had lower rheumatoid arthritis severity scores on average than never-drinkers.
How did the researchers interpret the results?
The researchers suggest that increased consumption of alcohol is associated with a significant dose-dependent reduction in susceptibility to rheumatoid arthritis and that there is a further association between higher frequencies of alcohol consumption and reduced severity of rheumatoid arthritis.
This study appears to show an association between a higher frequency of alcohol consumption and both reduced risk of developing rheumatoid arthritis and decreased severity of the disease. However, there are limitations to this study (many of which the researchers highlight), which mean that the conclusions should be interpreted cautiously:
- This study required the patients to recall their own alcohol consumption, meaning the patients and controls may have over- or under-estimated the amount of alcohol they had consumed.
- The study asked the participants about the frequency of their drinking rather than about how much they typically drank. As we cannot tell what quantities of alcohol were consumed, it is therefore possible that some individuals who drank less frequently might actually have consumed equal or greater amounts of total alcohol than those who drank more regularly.
- The study relied on one questionnaire and may not give an indication of people’s changing drinking patterns over time or long-term drinking habits.
- The questionnaire did not ask about the type of alcoholic drink the participants drank. Different drinks may have different effects owing to the other chemicals besides alcohol found in them.
- The questionnaire did not ask whether patients’ drinking habits had changed since their diagnosis. The study did find that the type of drug a patient was taking influenced how much they drank. Patients with rheumatoid arthritis may also drink less frequently because their disease may cause changes in their lifestyle, for example, people with a more severe disabling condition may drink socially less frequently.
- The patient group was older and had a higher proportion of women than the control group. Although the researchers attempted to account for this in their analysis, the differences in the two groups may have influenced the likelihood that people would be regular drinkers. Women and older individuals may be less frequent drinkers than younger men.
- This study only included white Caucasian people. It is not clear whether this research would be applicable to the UK population as a whole.
This study has a number of limitations, and because of these it is not possible at this time to say whether alcohol has a beneficial effect on rheumatoid arthritis. Follow-up research, such as a randomised controlled trial, is necessary to assess whether alcohol can have any effect on the severity of rheumatoid arthritis. As drugs taken for rheumatoid arthritis can have toxic effects on the liver, it is advised that patients avoid alcohol. People with rheumatoid arthritis should follow medical advice on drinking and speak to their doctor or pharmacist if they have any concerns.