Osteoarthritis: Ditch the Fish Oil?

It’s here…the first longitudinal study on the role of four different lipid variables—total saturated fatty acids, monounsaturated fatty acids, n-3 fatty acids, and n-6 fatty acids—and the development of osteoarthritis (OA) in humans.

Starting with the well-researched premise that inflammation and osteoarthritis are linked, a group of multicenter researchers set out to examine whether the levels of n-6 fatty acids affect inflammation and therefore OA development. Their work, “Fatty Acids and Osteoarthritis: The MOST Study,” was published in the July 1, 2021 edition of Osteoarthritis and Cartilage.

The Multicenter Osteoarthritis study (MOST), funded by the National Institutes of Health, contains data from 3,026 adults who either have or are at risk for OA (two clinical sites; 2003-2006). In this longitudinal observational research, the investigators analyzed 260 cases with incident symptomatic OA and 259 with incident radiographic OA.

Co-author David Felson, M.D., M.P.H. told OTW that they pursued this research because they had questions about whether fish oil and other anti-inflammatory fatty acids might affect pain or progression in OA. The researchers used regression analysis to test the association of each OA outcome with levels of saturated, n-3 and n-6 FAs adjusting for age, sex, body mass index, education, race, baseline pain and depressive symptoms.

“While fatty acids levels affect systemic inflammation and might thereby influence the occurrence of OA, we found no association of fasting levels of FAs [fatty acids] previously associated with inflammation and OA,” wrote the authors.

They even looked at the number of hand joints affected by nodules, seeking to determine whether factors influencing systemic inflammation might be easier to detect using a hand OA phenotype.

“In exploratory analyses, we did not identify any association between levels of FAs and nodular hand OA and therefore could not confirm that systemic factors may have a greater influence on hand than knee OA.”

They also hit a wall when it came to nodular hand OA, finding no significant association of fatty acids with this OA phenotype.

“This was a large well-done trial also that showed that fish oil did not help,” stated Dr. Felson to OTW. “We found no association between fatty acid levels and any osteoarthritis or pain outcome. These are not promising treatments.”