Brothers and sisters of osteoarthritis patients are twice as likely to develop the condition themselves, according to researchers in the East Midlands.
The research is the first large study of its kind
The study, carried out at Nottingham's City Hospital, also discovered that men were more likely to inherit the disease than women.
Osteoarthritis is a painful condition causing inflammation and loss of cartilage, most commonly in the knee.
Almost 500 patients with osteoarthritis took part in the research.
The researchers, writing in the Annals of Rheumatic Diseases, based their findings on 490 patients, 737 of their siblings aged over 40, and 1,729 other patients who had knee pain.
Knee X-rays were taken to find evidence of structural changes caused by osteoarthritis.
Getting older was established a one major risk factor for the condition.
But even allowing for other risk factors like weight, smoking and gender, the siblings were still found to be more than twice as likely to have knee osteoarthritis as the other patients in the study.
The research is the first large study of its kind and adds to the evidence of a genetic link to the condition.