The existence of geographical clusters of cases of inflammatory polyarthritis in a primary care based register
- aARC Epidemiology Unit, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, bNorfolk Arthritis Register, St Michaels Hospital, Aylsham, Norfolk
- Professor Silman
- Accepted 12 October 1999
Abstract
OBJECTIVES To determine whether there is any evidence that there are spatial clusters of rheumatoid arthritis in particular, and inflammatory arthritis in general.
METHODS Setting was a population based incidence register of inflammatory arthritis: the Norfolk Arthritis Register (NOAR). All cases identified between 1990–1995 were mapped to place of residence. Statistical evidence of clustering was determined by calculating Poisson probabilities in putative areas.
RESULTS Three clusters were identified including one small area (population 85) where five unrelated cases developed during this time period. There was no obvious greater disease homogeneity within clusters and no common environmental factors were identified.
CONCLUSION Rare clusters of inflammatory polyarthritis do occur. Their significance and cause remain to be elucidated.
Footnotes
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Funding: this study was funded by a programme grant from the UK Arthritis Research Campaign.
