Session Information
Date: Monday, November 6, 2017
Title: Epidemiology and Public Health Poster II: Rheumatic Diseases Other than Rheumatoid Arthritis
Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Background/Purpose: We previously found that lower levels of omega-3 fatty acids (n-3 FA) were associated with the presence of inflammatory arthritis (IA) as well as risk of developing incident IA in ACPA+ individuals without IA at baseline. Omega-6 fatty acids (n-6 FA) compete with n-3 FA for elongation and desaturation enzymes in the body that help determine the pro- and anti-inflammatory potential of these FA and their derivatives. Western diets tend to have a high n-6 to n-3 ratio that may promote the pathogenesis of inflammatory and autoimmune diseases. We examined the association between n-6 FA levels and the presence of IA/rheumatoid arthritis (RA) in ACPA+ individuals.
Methods: At Colorado-based health fairs from 2008-2014, 47 subjects without a previous diagnosis of RA tested positive for the ACPA, anti-cyclic citrullinated peptide (CCP3, Inova), and were recruited into a follow-up research study. At their immediate post-health fair research visit (baseline), 10 of these ACPA+ subjects were identified as having disease-modifying anti-rheumatic drug (DMARD)-naive IA. Of the 10 ACPA+ subjects with prevalent IA at baseline, 8 were classified as RA by 2010 ACR/EULAR Criteria. Findings in those subjects with IA were compared to those without IA. Specifically, n-3 and n-6 as percent of total lipids in red blood cell membranes (RBC) were measured. Logistic regression assessed the associations between baseline IA and RBC n-6 FA%, as well as the n-6 to n-3 ratio.
Results: Subjects with IA at baseline were more likely to be ever smokers and test positive for rheumatoid factor and C-reactive protein than those without IA (Table 1). In addition, we found that subjects with higher n-6 FA and linoleic acid levels had higher odds of IA (Table 2). Furthermore, analysis of the n-6 to n-3 ratio demonstrated that higher total n-6 FA % relative to total n-3 FA % in RBCs significantly increased the odds of IA by almost 3-fold (Table 2).
Conclusion: We found that a higher n-6 to n-3 ratio was associated with prevalent IA in this ACPA+ population. Building off our previous work, this suggests a potential beneficial role of n-3 FAs in decreasing the risk of transitioning from ACPA positivity to IA. Specifically, our findings herein suggest that decreasing the n-6 to n-3 FA ratio in the body, perhaps either via n-3 FA supplementation or diet may play a role in decreasing the transition from an ACPA+ state to IA, findings that warrant further investigation.
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Table 1: Descriptive Characteristics by IA status at Baseline, Colorado Health Fair Population, 2008-2014 |
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|
Variable |
Prevalent IA at Baseline (n=10) |
No IA at Baseline (n=37) |
p-value |
|
Age, yrs (mean ± SD) |
55.9 (10.3) |
55.9 (10.4) |
0.996 |
|
Age ≥ 50 yrs |
8 (80.0) |
26 (70.3) |
0.703 |
|
Sex: Female |
8 (80.0) |
21 (56.8) |
0.277 |
|
Race/Ethnicity: non-Hispanic White |
7 (70.0) |
29 (78.4) |
0.679 |
|
Education: > High school |
8 (80.0) |
32 (86.5) |
0.630 |
|
Income: > $40,000 |
7 (77.8) |
25 (71.4) |
1 |
|
Smoking: Ever |
9 (90.0) |
16 (43.2) |
0.012 |
|
Shared Epitope (SE)+ |
7 (70.0) |
16 (43.2) |
0.168 |
|
Omega 3 supplement use |
8 (80.0) |
19 (51.3) |
0.154 |
|
Rheumatoid Factor (RF)+ |
6 (60.0) |
5 (13.5) |
0.006 |
|
C-Reactive Protein (CRP)+ |
6 (60.0) |
7 (18.9) |
0.017 |
|
n-6 : n-3 ratio (mean ± SD) |
4.00 (1.41) |
3.14 (0.81) |
0.093 |
|
All values reported as n(%) unless otherwise stated. Fisher Exact p-values presented for categorical variables. Satterthwaite p-values reported for continuous variables. |
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Table 2: Adjusted analyses evaluating the relationship between omega-6 fatty acid % and IA at Baseline (N=47) |
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FA% in RBC |
OR (95% CI) |
p-value |
|
n-6 : n-3 FA ratio |
2.99 (1.11, 8.05) |
0.030 |
|
Total n-6 FA |
2.96 (1.12, 7.79) |
0.028 |
|
Linoleic acid |
2.63 (1.10, 6.29) |
0.030 |
|
Gamma linolenic acid |
4.91 (0.85, 28.35) |
0.075 |
|
Arachidonic acid |
0.81 (0.21, 3.22) |
0.768 |
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The n-6:n-3 FA ratio model adjusted for ever smoking status, SE, RF+, and CRP+; and the OR represents the odds of IA for each unit difference in the n-6:n-3 ratio. The n-6 models adjusted for ever smoking status, n-3 FA supplement use, SE+, RF+, and CRP+; and the ORs represent the odds of IA for a one standard deviation (SD) difference in the n-6 FA% in RBC. The SD for these variables are as follows: Linoleic acid: 1.72, Gamma linolenic acid: 0.06, Arachidonic acid: 1.37, Total n-6: 1.97. |
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To cite this abstract in AMA style:
Polinski KJ, Gan RW, Bemis EA, Demoruelle MK, Clare-Salzler MJ, Holers VM, Deane KD, Norris JM. Higher Omega-6 to Omega-3 Fatty Acid Ratio Is Associated with Increased Odds of Inflammatory Arthritis in a Health Fair Population Positive for Anti-Citrullinated Protein Antibodies (ACPA) [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/higher-omega-6-to-omega-3-fatty-acid-ratio-is-associated-with-increased-odds-of-inflammatory-arthritis-in-a-health-fair-population-positive-for-anti-citrullinated-protein-antibodies-acpa/. Accessed .« Back to 2017 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/higher-omega-6-to-omega-3-fatty-acid-ratio-is-associated-with-increased-odds-of-inflammatory-arthritis-in-a-health-fair-population-positive-for-anti-citrullinated-protein-antibodies-acpa/