Dr

Dr. Conclusion == Among African Americans, cigarette smoking is associated not only with the risk of autoantibody positive RA but also with the risk of autoantibody negative disease. RA risk attributable to smoking is limited to African Americans with more than 10 pack-years of exposure and is more pronounced among individuals positive forHLA-DRB1 SE. Keywords:rheumatoid arthritis, African Americans, cigarette smoking, rheumatoid NVP-TNKS656 factor, anti-CCP antibody,HLA-DRB1 shared epitope Since initial reports published more than twenty years ago (1), cigarette smoking has repeatedly been shown to be associated with rheumatoid arthritis (RA) susceptibility (210), a risk most pronounced among heavy smokers (2,11). Studies in populations of European ancestry have shown that the relationship of smoking with RA risk appears to be impacted by the presence ofHLA-DRB1 shared epitope (SE)containing alleles (7,12,13), but the mechanisms underpinning this interaction have yet to be fully defined. The associations of cigarette smoking with disease risk in populations of European ancestry also appear to be limited to those developing seropositive RA, which is characterized by the presence of either rheumatoid factor (RF) or anti-cyclic citrullinated peptide (CCP) antibody in the serum (2,6). Prior reports examining the association of cigarette smoking with RA risk have almost exclusively involved populations of European ancestry. The lack of such studies among African Americans represents an important gap in our knowledge. Although smoking is less frequent in African Americans than in persons of European ancestry (14), NVP-TNKS656 smoking incidence appears to be increasing in this population (15) and concomitant rates of smoking cessation in African Americans are consistently lower compared to Caucasians (16). It is unknown whether smoking contributes to RA risk in African Americans and whether this risk is impacted by the presence ofHLA-DRB1 SE, a genetic risk factor that is less prevalent in African Americans with RA than in individuals of European ancestry with RA (17). To address these knowledge gaps, we conducted a case-control study to examine the association of cigarette smoking with RA among African Americans, NVP-TNKS656 to assess the impact of cumulative exposure, and to define the extent to which this association is affected byHLA-DRB1 SEpositivity. == Patients and Methods == == Study population == RA cases and healthy controls were participants in the Consortium for the Longitudinal Evaluation of African-Americans with CALN Early Rheumatoid Arthritis (CLEAR) (1820). All cases satisfied the American College of Rheumatology (ACR) RA classification criteria (21) and all study participants self-reported African American race. Additional information regarding African American heritage (race/ethnicity of parents, grandparents) was not collected. This study included cases and controls from CLEAR-I (RA cases had 2 years disease duration from time of symptom onset) and CLEAR-II (cases with any disease duration). African American controls were enrolled based on age, gender, and geographic residence and NVP-TNKS656 were recruited predominantly based on lists of telephone numbers from individuals residing in the same mailing zip codes as those of RA cases. These lists were obtained from Genesys / Marketing Systems Group (http://www.m-s-g.com/default.htm). Telephone numbers were selected from census tracts with high percentages of African Americans near the sites enrolling cases. Controls were selected within an age range of 10 years based on the mean age of RA cases at each site at a female to male ratio of 3:1 based on the anticipated gender distribution in cases. Potential controls were called by interviewers to determine eligibility and interest and lists of suitable control subjects were then distributed to the sites to arrange study visits. RA cases and controls were enrolled through one of five sites: the University of Alabama at Birmingham (Birmingham, AL), Emory University (Atlanta, GA), Medical University of South Carolina (Charleston, SC), the University of North Carolina (Chapel Hill, NC), and Washington University (St. Louis, MO). The study was approved by the.