Geographical clustering of scleroderma in south and west London.

Anecdotal observation suggested a local increase in the occurrence of scleroderma within a borough in close proximity to a major airport. Ascertainment of all living cases was attempted within that borough and adjacent boroughs as well as a similar exercise in two further boroughs in close proximity to another major airport. The results showed a higher prevalence of scleroderma in all three study areas compared to that expected based on a population survey in another part of the United Kingdom adopting similar methodology. Further, within the boroughs there was a suggestion that the cases were not uniformly distributed but tended, in part, to cluster in those parts of the study areas that were in fact near to the airports under investigation. The increase in absolute risk was not sufficiently high to be consistent with a major environmental hazard. There is also no biologically plausible hypothesis for these observations. Nevertheless, the observation is of interest and might suggest further lines of inquiry for aetiological research.