The Role of Tobacco Use in RA
The Center for Disease Control (CDC) reports that 18% of Americans currently smoke, and smoking is the leading cause of preventable death in the United States.1 The good news is that the proportion of people who smoke has decreased from 42% in 1965 to the current 18%.2 While we’ve witnessed a dramatic change in public perceptions about, and decreases in overall use of tobacco products over the years, there remains concern about its role in rheumatoid arthritis.
In a summary of many studies, researchers demonstrated that lifelong smoking increased the risk of rheumatoid arthritis.3 In recent large study of over 35,000 RA patients, even light smoking was associated with increased risk of RA.4 While such studies don't actually determine that smoking directly causes RA, the relationship is strong enough to suggest that smoking is somehow involved in RA processes.
Smoking can be considered a possible trigger for RA. Researchers believe that smoking genetically triggers immune responses through something called citrullinated proteins.5Citrullinated proteins are involved in normal cell life but in autoimmune cases, these proteins leak out and the body responds by producing anti-citrullinated protein antibodies (ACPA or anti-CCP). Anti-CCP is currently one of the most accurate predictors of rheumatoid arthritis and is a commonly used diagnostic blood test. This connection between smoking and RA is only observed in people with a certain genetic profile who are typically rheumatoid factor (RF) or anti-CCP positive.6 While the connection between smoking and so-called seronegative RA patients is not yet evident via research, that doesn’t mean that it doesn’t exist.
Not only may smoking be involved in triggering RA, it may also be involved in disease severity and response to treatments. Researchers demonstrated that RA disease tends to be more severe in people who smoke.7 While such trends have been seen, other researchers note that smoking does not always predict a poorer prognosis and those relationships tend to be based whether or not a patient has a positive rheumatoid factor (RF) test.8 Smoking can also impact how a person responds to RA treatments. In some studies conducted in Sweden, it was noted that RA patients who smoke are less likely to respond to methotrexate and anti-TNF treatments.9
The emphasis thus far has been on tobacco smoking but the issue of smoking marijuana must be raised since it is often advocated as an alternative treatment for RA especially for pain relief. Given the fact that tobacco smoking is so intertwined with RA, and the fact that marijuana smoking produces hundreds of toxins whose impact on the body is unknown, it is probably a good idea for RA patients to not smoke any substance. If one decides to use medical marijuana, it is probably best to ingest it via eating, pill, spray or vaporizer.
Smoking has not been proven to cause RA but it is possible that it serves as an environmental trigger by impacting genetic processes in some people. And smoking may impact the severity of the disease and the potential for current treatments to work. For these reasons, RA patients should make all possible strides to quit the habit.
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