Dust from some jobs can increase the risk of RA
In recent years an increasing number of research results have indicated that the risk of rheumatoid arthritis (RA) increases when a person inhales health-hazardous dust in their work environment. One of the researchers studying this is Anna Ilar, who has a doctorate from and works at the Institute of Environmental Medicine at Karolinska Institutet.
RA is a disease that does not break out for a single reason. Instead, it is a combination of risk factors and hereditary conditions that work together. Smoking is the most well-known risk factor, which starts a reaction in the lungs. In the same way cigarette smoke is harmful, more and more research now suggests that exposure to dust and chemicals over the long term can also trigger RA among genetically susceptible individuals.
- It is positive and hopeful to find that there are factors we can prevent, says Anna Ilar. It can be nice to have an explanation or an increased understanding of why you got a certain illness. This may be the answer to some of them.
Anna Ilar has been looking into the connection between different professions and RA for some time:
- During my time as a master student, I examined the connection between occupation and an increased risk of rheumatoid arthritis, says Anna Ilar. We saw that, for example, electricians had an increased risk. It made me curious to try and find out why.
In the first published study, Anna Ilar continued to examine the link between occupation and increased risk of RA. In men, there was a doubled risk for people working in electricity and electronics as well as for machine operators, when compared to occupations such as office work. Among masons and concrete workers, the risk was almost three times as high. In women, there was a slightly increased risk among nurses and nurses.
The study took different types of living habits into account, such as smoking, alcohol habits and being overweight. Thus, the study pointed out that there may be something in the working environment of these groups that gave rise to the increased risk of suffering from RA. The project was based on results from the EIRA study, which examined the influence of both the environment and genetics on the origin and course of RA. The study was based on surveys from approximately 3,500 people with RA and 5,500 people without RA.
Quartz dust and asbestos pose an increased risk
A recent study investigated whether people who worked with quartz dust or asbestos had an increased risk of RA. The results showed that men who had been exposed to quartz dust or asbestos had an increased risk compared to workers who had not been exposed to these substances. This may explain the increased risk for those working in the construction industry and production-related professions. It could not be proven that women were at increased risk. But fewer women than men had worked in these environments and those who had been exposed had worked for a shorter time and were exposed to lower levels than their male counterparts.
- I did not expect such big differences between men and women, says Anna Ilar. When looking at professions in the EIRA study, we saw an increased risk, especially in men, compared to women. When we later gained access to a larger data material from different registries, we again did not see any increased risk among women. Then I began to understand that it was about the difference in men's and women's professions, linked to the tasks a person has done and how long a person worked in the job.
Organic dust - wood, animals, paper, textiles and flour
Studies have also looked at organic dust from wood, animals, paper, textiles and flour. There appeared to be a slightly increased risk of rheumatoid arthritis for people who had been exposed to dust from animals and textiles for a long time. The risk increases the longer a person has been in contact with the dust. Another project studied women in Malaysia who were exposed to textile dust in their work. The project was based on the MyEIRA study, which has a similar structure to the EIRA study but was performed in Malaysia. The results showed that the women who were exposed to textile dust also had an increased risk of RA. The risk was extra large for those who also carried the most known genetic risk factor.
Future research into the exposure to airborne substances
- It would be interesting to do similar studies in other countries, says Anna Ilar. Exposure levels of various substances can still be very high in many places. In Sweden, we have a very good work environment legislation. If we look at asbestos, for example, it was banned in Sweden during the 1980s and yet there is an indication that there is still an increased risk. But many countries still have no ban on asbestos and the exposure levels there are much higher than in Sweden.
Anna Ilar also believes that more studies are needed on exposure from other airborne substances such as welding gases and various metals. In addition, it would be good to look at how exposure affects the disease when a person is already affected by RA.
- We know there are several health benefits for people with RA if they stop smoking, says Anna Ilar. Could the same be true for exposure to these types of substances as well?
1. Ilar, A. Airborne occupational exposures and risk of developing rheumatoid arthritis. Institute of Environmental Medicine Thesis for doctoral degree (Ph.D.) 2019.