Sunlight Exposure, Sun-protective Behaviour, and Anti-citrullinated Protein Antibody Positivity: A General Population-based Study in Quebec, Canada

Naizhuo Zhao¹, Audrey Smargiassi², Ines Colmegna³, Marie Hudson⁴, Marvin Fritzler⁵ and Sasha Bernatsky⁶, ¹McGill University, Montreal, Canada, ²l’Université de Montréal, Montreal, Canada, ³The Research Institute of the McGill University Health Centre, Montreal, Canada, ⁴Division of Rheumatology, Jewish General Hospital, Montréal, QC, Canada, ⁵Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada, ⁶The Research Institute of the McGill University Health Centre, Montreal, ON, Canada

Meeting: ACR Convergence 2020

Keywords: Anti-citrullinated Protein Autoantibodies (ACPAs), Environmental factors, population studies, rheumatoid arthritis

Session Information

Date: Saturday, November 7, 2020

Title: RA – Diagnosis, Manifestations, & Outcomes Poster II: Biomarkers

Session Type: Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose: Sunlight exposure has been associated with lower rheumatoid arthritis (RA) risk, but to our knowledge, no one has ever studied sunlight exposure and anti-citrullinated protein antibodies (ACPA). Our objective was to examine associations between sunlight exposure and ACPA using general population data from Quebec, Canada.

Methods: A random sample of 7600 individuals (including 786 positive ACPA subjects and 201 self-reported rheumatoid arthritis, RA cases) from the CARTaGENE cohort was studied cross-sectionally. All subjects were nested in four census metropolitan areas, and mixed effects logistic regression models were used to calculate odds ratios (OR) and 95% confidence intervals (CIs) for ACPA positivity related to sunlight exposure, adjusting for sun-block use, industrial fine particulate matter (PM_2.5) exposures, smoking, age, sex, French Canadian ancestry, and family income. We also performed sensitivity analyses excluding subjects with RA, defining ACPA positivity by higher titers, and stratifying by age.

Results: The adjusted ORs and 95% CIs did not suggest conclusive associations between ACPA and sunlight exposure or sun-block use, but robust positive relationships were observed between industrial PM_2.5 emissions and ACPA (OR 1.19 per µg/m³, 95% CI 1.03 – 1.36 in primary analyses).

Conclusion: We did not see clear links between ACPA and sunlight exposure or sun-block use, but we did note positive associations with industrial PM_2.5. Future studies of sunlight and RA (or ACPA) should consider taking air pollution exposures into account.

Table 1. Adjusted odds ratios, OR (95% confidence intervals, CIs) for associations between sunlight exposures and ACPA positivity (>20 U/ml)

Disclosure: N. Zhao, None; A. Smargiassi, None; I. Colmegna, None; M. Hudson, None; M. Fritzler, Inova Diagnostics Inc, 5, 8, Werfen International, 5, 8; S. Bernatsky, None.

To cite this abstract in AMA style:

Zhao N, Smargiassi A, Colmegna I, Hudson M, Fritzler M, Bernatsky S. Sunlight Exposure, Sun-protective Behaviour, and Anti-citrullinated Protein Antibody Positivity: A General Population-based Study in Quebec, Canada [abstract]. Arthritis Rheumatol. 2020; 72 (suppl 10). https://acrabstracts.org/abstract/sunlight-exposure-sun-protective-behaviour-and-anti-citrullinated-protein-antibody-positivity-a-general-population-based-study-in-quebec-canada/. Accessed .

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