Sunlight Exposure, Sun-Protective Behavior, and Anti-Citrullinated Protein Antibody Positivity: A General Population-Based Study in Quebec, Canada

Arthritis Care Res (Hoboken). 2022 Feb;74(2):236-242. doi: 10.1002/acr.24448. Epub 2021 Dec 27.


Objective: To examine associations between sunlight exposure and anti-citrullinated protein antibodies (ACPAs) using general population data in Quebec, Canada.

Methods: A random sample of 7,600 individuals (including 786 subjects who were ACPA positive and 201 self-reported rheumatoid arthritis [RA] cases) from the CARTaGENE cohort was studied cross-sectionally. All subjects were nested in 4 census metropolitan areas, and mixed-effects logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) for ACPA positivity related to sunlight exposure, adjusting for sun-block use, industrial fine particulate matter (PM2.5 ) 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 and sex.

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 PM2.5 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 PM2.5 . Future studies of sunlight and RA (or ACPA) should take air pollution exposures into account.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Citrullinated Protein Antibodies*
  • Arthritis, Rheumatoid / immunology*
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Quebec
  • Sunlight*


  • Anti-Citrullinated Protein Antibodies