Does herpes zoster predispose to giant cell arteritis: a geo-epidemiologic study

Area of Science:

• Epidemiology
• Immunology
• Rheumatology

Background:

• Giant cell arteritis (GCA) is the most common systemic vasculitis in older adults, potentially leading to blindness.
• Varicella zoster (VZ) virus has been controversially proposed as an immune trigger for GCA.
• Geographic variations in GCA incidence exist, prompting investigation into potential environmental or infectious links.

Purpose of the Study:

• To examine the relationship between the incidence of herpes zoster (HZ) and GCA across different countries.
• To test the hypothesis that higher GCA incidence correlates with higher HZ incidence, suggesting a potential VZ virus role in GCA immunopathogenesis.

Main Methods:

• An ecologic analysis comparing GCA and HZ incidence rates (IRs) from 14 countries.
• Literature search for published IRs of GCA and HZ in populations aged 50 years and older.
• Statistical analysis using Pearson correlation and linear regression to assess the relationship between disease IRs.

Main Results:

• A negative correlation (r = -0.51) was observed between HZ and GCA incidence in 50-year-olds, indicating higher HZ rates were associated with lower GCA rates.
• Linear regression for 50-year-olds showed a statistically significant negative association (β = -2.92, p=0.025).
• No statistically significant correlation or association was found for 70-year-olds (r = -0.40, p=0.12).

Conclusions:

• The study found no positive biologic gradient supporting HZ as an immune trigger for GCA.
• Potential aggregation and selection biases inherent in geo-epidemiologic studies were acknowledged.
• The findings do not support a direct link between HZ incidence and GCA immunopathogenesis on a population level.