RESEARCH - Association of body fat with C-reactive protein in RA

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Arthritis Rheum. 2008 Sep;58(9):2632-41.

Association of body fat with C-reactive protein in rheumatoid arthritis.

Giles JT, Bartlett SJ, Andersen R, R, Fontaine KR, Bathon JM.

s Hopkins University School of Medicine, Baltimore, land.

OBJECTIVE: The serum C-reactive protein (CRP) concentration is

commonly used in rheumatoid arthritis (RA) as a surrogate marker of

systemic inflammation, presumably induced by synovitis. However, other

tissues, such as adipose tissue, can induce CRP production. This study

was undertaken to explore the associations between measures of

adiposity and CRP levels in RA.

METHODS: One hundred ninety-six men and women with RA underwent

anthropometric assessment and total body dual-energy x-ray

absorptiometry for measurement of total and regional body fat and lean

mass. The associations between measures of fat and lean mass and serum

levels of CRP and interleukin-6 (IL-6) were determined in analyses

stratified by sex, with adjustment for pertinent demographic,

lifestyle, and RA disease and treatment covariates as well as for the

potential modifying effects of articular activity and biologic

pharmacotherapeutic agents.

RESULTS: All measures of adiposity were significantly associated with

the level of CRP in women, but not in men. In women, the measure of

adiposity that showed the strongest association with the CRP level was

truncal fat, in which, in adjusted analyses, each kilogram increase

was associated with a 0.101-unit increase in the logarithmically

transformed CRP level (P < 0.001). Neither the level of articular

activity nor the use of biologic agents significantly modified this

association in women. However, in men, elevated articular involvement

was associated with a decreasing CRP level as truncal fat increased.

For all analyses, substitution of IL-6 for CRP produced similar

findings.

CONCLUSION: Adiposity is independently associated with CRP levels in

women with RA, and thus may confound the estimation of RA disease

activity when serum CRP concentration is used as a surrogate for

systemic inflammation.

PMID: 18759279

http://www.ncbi.nlm.nih.gov/pubmed/18759279

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