Study Affirms Osteoarthritis Not Inheritable

Let the genes off the hook. A family history of osteoarthritis (OA) or unspecified arthralgia was not predictive of developing rheumatoid arthritis (RA) according to a study in Sweden, reported by Diana Swift of MedPage Today.

“Although statistically significant familial co-aggregation was found for RA to every non-RA arthritis-related disease group—with no pronounced difference between seropositive and seronegative RA—there was no clinically meaningful association between relatives’ arthralgias or osteoarthritis and an individual’s risk of RA, ” wrote Thomas Frisell, Ph.D., of the Karolinska Institute in Solna, and his colleagues. He added that a family history of arthritis-related conditions conferred little or no additional risk.

The researchers made use of Sweden’s National Patient Register, and the country’s Multi-Generation Register to identify the first-degree relatives of index RA patients. They identified 54, 515 people with RA and 203, 141 first-degree relatives. Familial conditions studied included other inflammatory arthritis, juvenile idiopathic arthritis (JIA), spondyloarthropathies, psoriasis/psoriatic arthritis, lupus, connective tissue diseases, arthralgias, and OA.

The researchers found that the co-aggregation pattern of arthritis-related diseases was very similar for seropositive and seronegative RA. “The difference between seropositive and seronegative RA was significant for only two of the non-RA diseases—spondyloarthropathies and psoriasis/psoriatic arthritis, ” the authors wrote.

The investigators did find that some familial conditions were more strongly associated with RA. For example, a family history of juvenile idiopathic arthritis or a first-degree relative with lupus or connective tissue disease might be predictive. There were no marked differences among siblings, parents and offspring where familial risk was concerned. A consortium of Swedish research institutions sponsored the study.