Article Text
Abstract
Objective Previous studies, although inconclusive, have suggested possible associations of environmental risk factors with the development of giant cell arteritis (GCA). We aim to investigate seasonal influence on the incidence of GCA across Australia and New Zealand.
Methods In establishing an international study to investigate the molecular aetiology of GCA, archived temporal artery biopsy (TAB) specimens primarily from Australia and New Zealand were obtained. Demographic details including age, sex and date of TAB were collected from collaborating pathology departments. The season in which GCA was diagnosed was determined and compared with previous reports investigating the association between environmental risk factors and GCA.
Results Our study comprises data from 2224 TAB-positive patients with GCA; 2099 of which were from patients in Australia and New Zealand. The mean age at time of diagnosis was 76.4 years of age. The female-to-male ratio was 2.2:1. We noted equal distribution of the incidence rate across all four seasons (530–580 cases diagnosed every quarter). Statistical analysis of seasonal variation by Poisson regression and cosinor methods showed no incidence preponderance across seasons. Our results do not support a seasonal component contributing to the onset of disease. Our literature search identifies no consistent environmental risk factor in association with GCA.
Conclusion This is the largest GCA data set reported outside of Europe. Our results demonstrate equal distribution of the incidence rate across all four seasons. In contrast to some earlier reports, we did not identify evidence of a seasonal component contributing to the onset of disease.
- giant cell arteritis
- temporal arteritis
- epidemiology
- environment
- geography
- risk factor
- seasons
- latitude
- temporal artery biopsy
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Footnotes
Contributors All authors have contributed to this manuscript.
Funding This work was supported by funding from the Australian National Health and Medical Research Council (NHMRC). CERA receives Operational Infrastructure Support from the Victorian Government.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Collaborators Benhur Amanuel, Michael Awadalla, Matt A Brown, Celia Chen, Svetlana Cherepanoff, Linda Clarke, Jamie Craig, Katie Cremin, Erika de Guzman, Elisabeth De Smit, Jonathan Dick, Mitali Fadia, Cindy Forrest, Anthony Gill, Ruta Gupta, Helen Harris, Andrew Harrison, Alex W Hewitt, Catherine L Hill, Claire Hooper, Patrick Hosking, Jost Jonas, Lisa S Kearns, Sonja Klebe, Anthony Landgren, Soon Lee, Trische Y-M Leong, David Mackey, Roslyn Malley, Peter McCluskey, Daniel Mckay, Penny McKelvie, Catriona McLean, Tony Merriman, Andrew Miller, Andrulis Mindaugas, Logan Mitchell, Vince Murdolo, Min Ru Qiu, Thomas Robertson, Meena Shingde, Lisa Stamp, LayKhoon Too, Rob Verdijk, Tersia Vermeulen, Owen White, David Williams, Christine Younan, Nikolajs Zeps