In this study, the researchers compared the incidence of hand osteoarthritis diagnosed in specialist care, many times by a rheumatologist, in identical and non-identical twin pairs. It was found that hand osteoarthritis in both twins was significantly more common in identical twins than in fraternal twins. This indicates that genetic factors are important.
It is known that identical twins share 100% of their genes while fraternal twins share 50% of their genes, just like non-twin siblings. When twin studies are done, these differences can be exploited to study a genetically determined disease or a genetically determined condition (heritability). For example, it is known that eye color has a heritability of 98% while cancer has a heritability of 33%.
The new study in which Swedish twin pairs have been studied shows that hand osteoarthritis has a heritability of between 48% and 87%, which is high compared to previously known factors such as eye color and cancer.
The study is the first in which the researchers followed an entire twin population over several years and were thus able to study clinically relevant hand osteoarthritis. In the past, it has only been possible to study X-ray images of the hands in small selective samples where the twins themselves had to sign up for research and they can therefore not be considered representative of everyone. The researchers believe that this study is important when learning more about different subtypes of hand osteoarthritis and it also emphasizes the importance of learning more about which genes play a role in the development of osteoarthritis.
The study, which is i.a. conducted by researchers at Lund University and parts of the research group behind The Arthritis Portal can be read in its entirety. It opens in a new tab on the oarsijournal.com page when you press here.
