Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Science

Program

Epidemiology and Biostatistics

Collaborative Specialization

Musculoskeletal Health Research

Supervisor

Barra, Lillian

2nd Supervisor

Stranges, Saverio

Co-Supervisor

Abstract

Rheumatoid arthritis (RA) is associated with increased risk of cardiovascular disease (CVD). This thesis first explored risk factors affecting this association using a scoping review. The review included 33 cohort studies and showed that older age, male sex, co-morbid hypertension, diabetes, and/or dyslipidemia, the presence of rheumatoid factor (RF) and/or acute phase reactants, and glucocorticoids were associated with higher CVD incidence in RA patients. Using data from the Canadian Longitudinal Study on Aging (CLSA), Cox regression was used to explore whether RA increased CVD incidence among middle age and older individuals, accounting for various comorbidities, demographic, lifestyle and RA-related factors. RA patients experienced significantly more CVD incidence, compared to non-RA individuals (IRR = 1.69, 95% CI: 1.34 – 2.11). The stratified analysis showed that sex, age and education level were effect modifiers in the relationship between RA and CVD incidence.

Summary for Lay Audience

Rheumatoid arthritis (RA) is an autoimmune disease where immune system, which normally protects the body against infections, attacks joints mistakenly. RA also causes systemic inflammation which can affect other organs of the body, especially heart and blood vessels. The goal of this thesis is to assess whether RA patients are at higher risk of heart disease compared to individuals without RA and explore effects of other factors on this association.

This thesis included two parts. The first part was a review of current scientific literature to explore the risk factors associated with new cases of heart disease among patients with RA. The review included thirty-three studies. The following factors were shown to be associated with an increased risk of heart disease in RA patients: older age, male sex, high blood pressure, diabetes, and/or high cholesterol, the presence of indicators of inflammation such as rheumatoid factor (RF) and/or acute phase reactants. Additionally, certain antirheumatic medications such as glucocorticoids were shown to elevate risk of heart disease while another category of drugs named disease-modifying anti-rheumatic drugs (DMARDs), were associated with a lower risk of heart disease.

The second part was a long-term study using data from the Canadian Longitudinal Study on Aging (CLSA) cohort to study this issue further. This study included 19,844 individuals and showed that RA patients are at approximately twice higher risk of developing heart disease, compared to those without RA. Additionally, elevated level of indicators of inflammation (CRP), DMARDs other than methotrexate, male sex, older age, low physical activity level, smoking, dissatisfaction with sleep quality, diabetes, high blood pressure and mood disorder were found to be risk factors of heart disease among RA patients. Lastly, the results revealed that RA disproportionally affects cardiovascular health among females, individuals aged < 65 years and individuals with lower education level.

Overall, RA patients are at higher risk of heart disease, and various comorbidities, behavioral and demographic factors affect this association. Future research should study underlying mechanisms for higher risks among females, younger individuals and those with lower education level, to better prevent and manage heart disease in these populations.

Available for download on Wednesday, October 01, 2025

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