Recent research into risk factors for developing RA

Can known lifestyle risk factors be modified to help reduce the risk of rheumatoid arthritis?

Taken from: NRAS magazine, Spring 2012
 
A major literature search has been undertaken to look at published evidence between 1948 and early 2011 for possible risk factors in people’s lifestyles that could be controlled to reduce the risk of inflammatory arthritis and RA.
 
From the information collected, smoking has been confirmed as a major risk factor for developing RA, this is particularly strong for people who are anti-CCP positive. The risk is also related to the level of smoking and is more evident in males than in females. However, the study shows that it is necessary to stop smoking for 20 years before the increased risk of developing RA is cancelled out.
 
Dietary factors were looked at but only had a weak association. Some studies suggest that antioxidants in the diet are protective. [Major sources of antioxidants in the human diet are varied and include cereals, fruits, vegetables, chocolate, oils and beverages such as tea, coffee, wine and fruit juices.] High coffee consumption may increase the risk of RA but alcohol intake (especially in smokers) may help to reduce the risk. There is an increased risk for those with obesity but only in the seronegative group.
 
Pregnancy is known to reduce the activity of RA but studies have failed to show an association of pregnancy or parity with the risk of RA. Breast feeding may reduce the risk of developing RA. The contraceptive pill has been shown in some studies to have a protective effect eg the NOAR study in Norfolk, but other studies have not found this. Higher social class and educational achievement were found to be protective.
 
Further research evidence is needed to add to the body of knowledge of common risk factors for RA. This will be invaluable to support health strategies aimed at preventing RA. Prevention of RA has to be the ultimate goal just as systems are now well established to prevent many cancers and heart and stroke disease. 


Pulmonary dysfunction, smoking, socio-economic status and the risk of developing rheumatoid arthritis

Taken from: NRAS magazine, Winter 2011
 
This large scale study conducted at the Lund University, Malmö, Sweden, looked at the environmental risk factors that are of potential interest for both prevention and treatment of RA, in particular, the effect of lung function, smoking and socio-economic status.
 
The study looked at data collected between 1974 and 1992 from 22, 444 men and 10, 902 women who were included in the Malmö Preventive Medicine Program (MPMP). Individuals who developed RA were identified by linking the MPMP database to national and local RA registers.  290 cases of new onset incident RA were identified (151 men/139 women; mean age at diagnosis 60 years).  They concluded that lung dysfunction did not predict RA, but smoking and low socio-economic status were independent risk factors for RA. Other effects of smoking may be important for RA susceptibility. 


Promising research on a potential cause of rheumatoid arthritis

Taken from: NRAS magazine, Autumn 2011
 
Little is known about why the body’s own immune system starts to attack healthy tissue in auto-immune conditions like rheumatoid arthritis. However, recent research performed at the Kennedy Institute of Rheumatology, Imperial College might offer a clue to the cause of RA in some. It is thought that a bacterial molecule that is known to be one of the major causes of periodontitis (a condition where the tissue that surrounds and supports the teeth becomes inflamed) may also be the cause in some cases of RA. If this is the case, this offers fresh hope that we will one day be able to treat and prevent these cases with the use of medication that will inhibit this molecule. 


Could alcohol intake affect the likelihood of developing rheumatoid arthritis?

Taken from NRAS magazine, Autumn 2011
 
Many rheumatoid arthritis patients will be aware that they need to limit their alcohol consumption while on some medications. On methotrexate, for example, patients are advised to stay well within the maximum daily limits for alcohol consumption of 2-3 units for women and 3-4 units for men, and particularly that they should try not to exceed this in one sitting (ie not to have their weekly allowance all on one day).
 
However, recent research has also shown that alcohol may have an impact on whether or not someone develops inflammatory polyarthritis (ie conditions such as rheumatoid arthritis, that affect multiple joints). Though the exact causes of rheumatoid arthritis are unknown, it has already been well established that people who smoke are more likely to develop rheumatoid arthritis.
 
Dr Lahiri presented findings from the EPIC-Norfolk study and the Norfolk Arthritis Register (NOAR) at this year’s annual EULAR conference. One of the difficulties in analysing the results of this study was that people who were considered ‘heavy’ drinkers were also more likely to be smokers. However, even adjusting for this, it was felt that by reducing alcohol intake there could be as much as a 16% reduction in the risks of developing polyarthritis for every unit per day less of alcohol that was consumed, making heavy alcohol consumption a strong risk factor for developing RA.


Sex hormone linked to the development of rheumatoid arthritis

Taken from: NRAS magazine, Spring 2009
 
Researchers in India have published their findings of work in mice showing that sex hormones play a role in the development of rheumatoid arthritis (RA). 

The researchers commented that it was well known that women are significantly more likely to develop RA than men, indicating that sex hormones like oestrogen and testosterone could be important, but their role is not well understood. Hence more work is needed in this area.
 
In their report, the researchers suggested that oestrogen might reduce inflammation by suppressing tumour-necrosis factor (TNF) levels. 


Does loss of sleep increase the risk of rheumatoid arthritis?

Taken from: NRAS magazine, Spring 2009
 
New research from the US has suggested that losing sleep may increase the risk of rheumatoid arthritis (RA). This could be because lack of sleep could lead to the key cellular pathway that produces tissue-damaging inflammation, which would therefore increase the risk of diseases such as RA. Much more work needs to be done in this area.