Knee osteoarthritis, which causes inflammation and loss of cartilage in joints, is likely to be more painful for smokers, say US scientists.
Researchers led by David Felson, a professor at the Boston University Medical School, studied 159 men with symptomatic osteoarthritis of the knee for 30 months. Twelve percent of the participants were current smokers, reported the online edition of BBC News.
The researchers found that smokers had a progressive form of the disease and suffered higher levels of pain.
Magnetic resonance imaging (MRI) scans of the knee showed that the smokers had a two-fold higher risk of cartilage loss in knee joints - a process that occurs as the disease progresses.
Men who smoked also had more pain than those who didn't smoke throughout the study.
Osteoarthritis is much more common in women but there were too few female smokers in the study to measure the effect on them.
However, Felson said the results would probably be the same for women. "There is no reason for it to be different in women as I don't think biology is likely to be different. But we can't be sure."
"It's an additional reason to stop smoking as it may lessen the pain and rate of cartilage loss," he added.
Osteoarthritis - degenerative arthritis - is caused by the breakdown and loss of cartilage in one or more joints.