As we talked in class, it is known that women are more likely to develop the disease than men. Sex hormones are suggested to play a role in the pathogenesis of rheumatoid arthritis (RA). I came across an interesting article about the association between sex hormones and RA that is fresh off the press. The findings in this article are based on a Swedish study that was done on a pool of male participants who developed RA, using male participants who did not develop the disease as the control group. After adjusting for smoking and body mass index (variables which can affect the risk of RA), the researchers found that there were significantly lower levels of testosterone in the blood samples of rheumatoid factor-negative RA compared to the control group.
You may ask, wait...doesn't rheumatoid factor(RF)-negative mean that the participants would not get the disease since RF is an antibody that is found in RA patients? A negative RF does not rule out RA; some individuals with RA will produce blood tests that are seronegative for the antibody in the early stage of the disease. Over time, it is likely that they will become seropositive for RF. Also, we must remember that RF is found in the serum of patients with other chronic infections as well; RF is not specific for RA.
The researchers found that there was not much of an association between testosterone levels and RF-positive RA men, so the lower testosterone levels were only statistically significant in RF-negative RA men. Also, FSH levels were observed to be significantly increased in RF-negative RA men (but decreased in RF-positive RA men). This suggests that hormonal changes precede the onset of RA and could affect the severity and phenotype of the disease. The researchers seem to conclude that perhaps the levels of testosterone and FSH have an effect on the characteristics of the disease, such as whether the RF antibody is detected in RA, etc. Why do you think low testosterone levels were not as strongly associated with RF-positive RA men as they were with RF-negative RA men?
Something that is still unclear is whether low testosterone is a contributory factor or a consequence of RA. What are your thoughts on this?
Also, do you agree that sex hormones could be the reason why more women get the disease than men? Would an identical study done with women be helpful?
Any other thoughts?
This article interested me, because we have recently been talking about menopause putting women as risk of illnesses such as cardiovascular disease. It is also important to note that men go through andropause, where testosterone and DHEA start to decline. In research I have read, Rheumatoid Arthritis (RA) usually affects those that are middle aged. However, because this illness is an autoimmune type disease it can occur at any stage in life. To answer Angela's question, maybe for the older patients that are afflicted by the illness the declining testosterone is a contributing factor to RA. I would be interested to see if that were the case in osteoarthritis patients. Osteoarthritis is more concerned with wear and tear/old age. It is possible that testosterone might provide a protective effect towards the joints before andropause.
ReplyDeleteThe other question Angela brought up in her blog has to do with the prevalence of RA in men vs. women. We know that RA is more common in women then men. I do not think that this is due to the sex hormones, but due to the fact that autoimmune diseases are more common in women.
There seems to be a large range of issues related to low testosterone in addition to rheumatoid arthritis. What’s most unfortunate is that it still seems as if research cannot confidently identify low testosterone as a direct cause of many of these issues, including RA. What has been confirmed is the “relationship” between low testosterone and certain diseases. As this article mentioned, a “correlation” has been discovered between RA and low testosterone, whether it is a cause or product of RA is still in question. Like Angela mentioned in her post, my intuition would lead me to believe that rheumatoid factor-negative would indicate an absence of RA, which seems to be related to low testosterone. This could suggest that perhaps it’s not necessarily the low testosterone that’s causing these internal changes, but maybe it’s the “transition” from normal to low testosterone. There has been much speculation that low testosterone is linked with a weakened immune system, so maybe the process of diminishing testosterone levels is affecting the immune system in ways that can cause the characteristic joint degradation of RA. Because the onset of RA is rather slow, this slow progression can be juxtaposed with the slow decreasing levels of low T.
ReplyDeleteHowever, if research can prove that low testosterone is actually a “cause” of RA, then this could lead to a large number of potential therapies. Although, the supplementation of testosterone has its own set of problems… which we won’t worry too much about right now…
Erin, you make a great point that low testosterone may be a contributing factor to RA for older patients. I like how you brought up the topic of andropause. I think that's really important to consider; it would be interesting to take a group of arthritic men, make age and testosterone levels the main variables, and perform a study to discover a correlation (or lack thereof) between age and testosterone. And I agree, I believe that it would be even more interesting to see this study (from the article) done on osteoarthritic patients.
ReplyDeleteRichard, I agree with you about the transition from normal to low testosterone being more concerning than simply low testosterone levels. To answer my own question, I do think that low testosterone is a contributory factor of RA rather than a consequence, but only when it is resulting from hormonal changes. Like Erin said, hormonal changes as you age (resulting from andropause in men and menopause in women) seem to have a mysterious but undoubtedly huge role in inducing RA. Like you said, Richard, I think that so much more research needs to be done in this area, and if we can identify and test the most crucial factors in RA, there should be a lot of good progress.
I think it would be interesting to see if women with higher testosterone levels were less like to develop RF-negative RA. One question I did have is whether women are more more like to develop RF-negative or RF-positive RA? This could be an interesting method of defining how we treat the two types and if hormone regulation is an option of either.
ReplyDeleteVery informative. There are some men who are encounter problems in terms of their low testosterone level. They are looking for health supplements to increase their T-levels but as I read the related article of this blog, using testosterone supplements has a negative effects. Is it really advisable to use testosterone supplements?
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