BALTIMORE, Maryland—Adiposity may protect rheumatoid arthritis (RA) patients from radiographic joint damage via low levels of adiponectin, according to new research in the September 15, 2009 issue of Arthritis Care & Research.¹

But trying to reduce adiponectin to stave off RA joint damage might harm the heart.

“Adiponectin may represent a mechanistic link between low adiposity and increased radiographic damage in RA,” conclude the researchers who were led by Jon T. Giles, MD, of the Johns Hopkins University School of Medicine in Baltimore. “Adiponectin modulation may represent a novel strategy for attenuating articular damage.”

Adiponectin: good for heart, bad for joints?

“Targeting adiponectin may be beneficial in preventing articular damage in patients with RA. However recognizing the beneficial effects of adiponectin on cardiovascular risk, any effect on radiographic progression of systemically reducing adiponectin could be accompanied by an increase in cardiovascular disease,” the study authors conclude. ”Conversely, attempting to improve the elevated cardiovascular risk of patients with RA by reducing visceral fat (with diet and exercise for example) and increasing adiponectin levels could serve to undesirably accelerate joint damage.”

In the new study, 197 RA patients underwent total-body dual x-ray absorptiometry for measurement of total and regional body fat and lean mass, abdominal computed tomography for measurement of visceral fat area, and x-rays of their hands and feet which were scored according to the modified Sharp/van der Heijde (SHS) method.

The researchers also measured blood levels of adipokines. Adiponectin levels showed a strong association with x-ray damage, with the log SHS score increasing by 0.40 units for each log unit increase in adiponectin after adjusting for pertinent predictors of radiographic damage, the study showed. Specifically, adiponectin independently accounted for 6.1% of the explainable variability in SHS score. This is comparable with rheumatoid factor, and greater than HLA-DRB1 shared epitope alleles or C-reactive protein levels, the researchers conclude.

Other serum adipokines including resistin and leptin were not associated with radiographic damage. There was an inverse association between visceral fat area and radiographic damage that was attenuated when adiponectin was modeled as a mediator. Moreover, the association of adiponectin with radiographic damage was stronger in patients with longer disease duration, the study showed.

Reference

1. Giles JT, Allison M, Bingham III CO, et al. Adiponectin is a mediator of the inverse association of adiposity with radiographic damage in rheumatoid arthritis. Arthritis Care & Research. 2009;61:1248-1256.