RESEARCH - Cigarette smoking, disease severity, and autoantibody expression in African Americans with recent-onset RA

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Ann Rheum Dis. Published Online First: 15 January 2008.

doi:10.1136/ard.2007.082669

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Extended Report

Cigarette smoking, disease severity, and autoantibody expression in African

Americans with recent-onset rheumatoid arthritis

Ted R Mikuls 1*, B 2, O Westfall 2, V Holers 3,

Lezlie Parrish 3, van der Heijde 4, Maaltje van Everdingen 4,

Graciela S Alarcon 2, Doyt L Conn 5, Beth Jonas 6, Leigh F Callahan 6, Edwin

A 7, Gilkeson 7, 2, Larry W Moreland 8 and S Louis

Bridges Jr2

1 University of Nebraska, United States

2 University of Alabama at Birmingham, United States

3 University of Colorado, United States

4 Leiden, Netherlands

5 Emory University, United States

6 University of North Carolina, United States

7 Medical University of South Carolina, United States

8 University of Alabama, currently at University of Pittsburgh, United

States

Abstract

Objective: To examine the association of smoking with clinical and serologic

features in African Americans with recent-onset rheumatoid arthritis (RA)

and to explore whether this association is dependent on the presence of the

HLA-DRB1 shared epitope (SE).

Methods: In African Americans with recent-onset RA (n = 300), we examined

the association of cigarette smoking (current vs. past vs. never and

pack-years of exposure) with anti-CCP antibody, rheumatoid factor (RF) (-IgM

and -IgA), rheumatoid nodules, and baseline radiographic erosions using

logistic and cumulative logistic regression (adjusting for SE status). We

also examined for evidence of interaction between smoking status and SE for

all outcomes.

Results: Although there was no association with RF-IgA seropositivity,

current smokers were approximately twice as likely as never smokers to have

higher IgA-RF concentrations (based on tertiles; OR = 1.74; 95% CI

1.05-2.88) and nodules (OR = 2.43; 95% CI 1.13-5.22). These associations

were most pronounced in those with more than 20 pack-years of exposure.

There was no association of smoking status or cumulative tobacco exposure

with anti-CCP antibody, IgM-RF, or radiographic erosions. There was also no

evidence of a biologic or statistical SE-smoking interaction for any of the

outcomes examined.

Conclusion: This is the first study to systematically examine the

association of cigarette smoking with RA-related features in African

Americans. Cigarette smoking is associated with both subcutaneous nodules

and higher serum concentrations of IgA-RF in African Americans with RA,

associations that may have important implications for long-term outcomes in

this population.

http://ard.bmj.com/cgi/content/abstract/ard.2007.082669v1?papetoc

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