A study helps quantify how much having rheumatoid arthritis, or RA, puts people at risk of developing chronic obstructive pulmonary disease, or COPD, one of the most common types of lung disease. Although the link between the two was known, Israeli researchers found that people with RA are twice as likely to have COPD than those without RA.

“I believe that certain individuals carry [a group of genes] that turn them susceptible to both diseases,” explains lead researcher Howard Amital, MD, of the Sheba Medical Center in Israel, who presented his findings in May at the 2011 annual meeting of the European League Against Rheumatism (EULAR).

COPD has two main forms: chronic bronchitis, defined by a long-term cough with mucus, and emphysema, defined by destruction of the lungs over time. Cigarette smoking is the leading cause of COPD.

Dr. Amital and his team analyzed data from 15,766 patients with RA and an almost equal number of people without the autoimmune condition from the database of Israel’s largest healthcare provider. After adjusting for age, smoking status, obesity and other confounding factors, they found the prevalence of COPD was 8.9 percent in the RA group, compared to 4.4 percent in the healthy group.

The researchers say it appears some people have certain predisposing genetic elements that smoking exacerbates. “It seems that the smoking elicits an autoimmune reaction that causes rheumatoid arthritis and COPD,” says Dr. Amital.

James O’Dell, MD, a practicing rheumatologist at the University of Nebraska Medical Center in Omaha, says the study findings offer further evidence of the association in a large study sample.  

“We already have said that COPD was more common in rheumatoid patients than those who don’t have it. It seems the autoimmune process – maybe the genetic background of a patient with RA – is a risk factor for developing rheumatoid and other inflammatory responses like COPD,” Dr. O’Dell explains.

These study findings are preliminary and the study doesn’t specify if the RA patients who got COPD were smokers, although Dr. O’Dell says it’s rare for COPD to develop in a non-smoker.

But since smoking is a risk factor for developing RA – and for making the RA more severe – he says the message for patients who are still lighting up remains: Stop.  

“If we were trying to give people advice – they can’t do anything about having RA or not. What we can do is decrease their risk factors for developing COPD,” Dr. O’Dell says.