People with rheumatoid arthritis (RA) are twice as likely as healthy people to have chronic obstructive pulmonary disease (COPD), according to a new Israeli study.

The researchers presented the study at the European League Against Rheumatism annual conference in London.

“We know that similar changes in core physiological processes cause symptoms in RA and COPD, and we hope that the results of our study prompts new research into potential links between altered genetic and autoimmune processes in the two conditions,” said researcher Dr. Howard Amital of the Sheba Medical Center.

RA is an autoimmune disease that causes pain and swelling in the joints as well as other parts of the body such as the lungs or mouth.

With data from Israel’s largest health care provider, Clalit Health Services, the researchers were able to compare the information of nearly 16,000 RA patients over the age of 20. Each participant was matched for age and gender with the study, including over 15,000 healthy controls such as smoking, lifestyle habits or obesity.

They found that COPD showed up in 8.9 percent of RA patients compared with only 4.4 percent in the healthy controls.

The findings are considered preliminary.