In a nutshell
This study examined whether there is a genetic basis for hip fractures in patients with rheumatoid arthritis.
Some background
Patients with rheumatoid arthritis have a higher risk of developing osteoporosis. Osteoporosis is a bone disease which causes bone loss (decreased bone mass and bone density). This in turn leads to the bones becoming brittle and fragile and increases the risk of them breaking. As a results of osteoporosis, patients with rheumatoid arthritis are at increased risk of suffering from bone fractures.
Recent European research suggests that the risk of osteoporosis may be related to the patients’ genetics. One of the genes reported to be mutated is osteoprotegerin (OPG). The mutation leads to increased function of OPG which leads to increased bone resorption (breaking down of bone). Whether this genetic risk is also true for patients with rheumatoid arthritis has not yet been shown.
Methods & findings
2,282 patients with rheumatoid arthritis were included in this study. Their DNA samples were examined for genetic differences in 6 genes (OPG, ZBTB40, MHC, RANK, SPTBN1 and LRP4) which had previously been associated with hip fractures. Patients were followed for up to 10 years and the number of hip fractures was recorded.
Over the course of the follow-up 40 patients suffered from hip fractures. The risk of hip fractures was 2.5 times higher for patients with mutated OPG. There was no link between the risk of hip fracture and the 5 other genes examined.
The bottom line
The authors concluded that the mutated OPG is associated with increased risk for osteoporosis-associated hip fracture in patients with rheumatoid arthritis. They suggest that the results could contribute to better understanding of osteoporosis and to the development of models that could predict fracture risk for patients.
The fine print
This study only included Japanese patients with rheumatoid arthritis. The results may need to be repeated in other patient groups.
Published By :
PLOS ONE
Date :
Aug 08, 2014
