Gene-Environment Interactions in Rheumatoid Arthritis Autoimmunity Disease Severity

Study Overview
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Brief Summary
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The objective of the proposed study is to assess the role of smoking and complex gene-smoking interactions in two understudied Rheumatoid Arthritis (RA)groups.

Detailed Description
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Rheumatoid Arthritis (RA) is a systemic inflammatory disease affecting over 2 million people in the U.S. alone, a condition characterized by progressive joint destruction, significant work-related disability and accelerated mortality. While the precise cause of RA is unknown, it is clear that the disease does not result from a single heritable factor or single environmental exposure. Of the many environmental exposures that have been studied, cigarette smoking is the factor most consistently shown to be associated with RA onset. In addition to its role in disease susceptibility, recent studies have found that smoking, along with genetic factors, contribute to RA-related autoimmunity and disease severity. Moreover, studies to date looking at disease severity in RA have exclusively involved women of Caucasian/European ancestry. This is an important distinction since although RA is more common in women, smoking appears to be most closely linked to RA risk in men. Additionally, the burden of other smoking-related illnesses appears to be greatest among non-Caucasian populations. For this reason and because smoking rates and prevalence of risk-alleles differ in ethnic/racial minorities (i.e. SE and GSTM1-null polymorphism), further studies are needed to define the association of smoking and possible gene-smoking interactions and their role in autoimmunity and disease severity in these understudied populations.

Official Title
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Gene-Environment Interactions in RA Autoimmunity Disease Severity

Conditions
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Rheumatoid Arthritis

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Meeting ACR criteria for RA Exclusion Criteria: No exclusions

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| I Multicenter Veteran's Affairs Rheumatoid Arthritis (VARA) registry<br>multicenter Veteran Affairs Rheumatoid Arthritis (VARA) registry | |
| II NIH-funded Consortium for the Longitudinal Evaluation of African Americans with Early RA (CLEAR)<br>NIH-funded Consortium for the Longitudinal Evaluation of African Americans with Early RA (CLEAR) | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rheumatoid factor (RF) antibody status and concentration | Rheumatoid factor (RF) antibody status and concentration. RF is an autoantibody that responds to inflammation caused by RA. | baseline | 
| Anti-CCP antibody status and concentration | Anti-CCP (cyclic citrullinated peptide antibodies) antibody status and concentration. The normal level of anti-CCP antibodies is less than 20 units/mL. Anything over this level means a positive test. Anti-cyclic citrullinated peptide antibody titer predicts time to rheumatoid arthritis onset in patients with undifferentiated arthritis. | baseline | 
| Evidence of radiographic erosions and scoring. | Evidence of radiographic erosions and scoring. Erosions are graded from 0 to 4 (0 = normal; 1 = questionable; 2 = definite but mild; 3 = moderate; and 4 = severe). This method requires a standard reference set of radiographs for comparison. The range of erosion scores is from 0 to 128 in the hands, and from 0 to 48 in the feet. | baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Smoking status and cotinine levels | Smoking status and cotinine levels are recorded. Cotinine is measured in nanograms per milliliter (ng/mL): Cotinine levels in a nonsmoker are generally less than 10 ng/mL. Cotinine levels in a light smoker or someone exposed to secondhand smoke are 11 ng/mL to 30 ng/mL. Cotinine levels in a heavy smoker may be more than 500 ng/mL. | baseline | 
| Genotyping of the FSTM1, NAT1, NAT2, and mDEH genes | Samples will be taken to genotype FSTM1, NAT1, NAT2, and mDEH genes which are important in carcinogenesis. | baseline | 
| Racial/ethnic composition and disease characteristics | Both racial/ethnic composition and disease characteristics are recorded for analysis. | baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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rheumatoid arthritis, cigarette smoking, gene-environmental interactions, autoimmunity, disease severity