Journal of Public Health Medicine 25:351-357 (2003)
© Faculty of Public Health 2003; all rights reserved.
Cement, cancers and clusters: an investigation of a claim of a local excess cancer risk related to a cement works
Richard J. Roberts, Consultant in Public Health Medicine and Honorary Senior Lecturer
North Wales Health Authority, Preswylfa, Hendy Road, Mold CH7 1PZ
John Steward, Director
Gareth John, Senior Statistician
Welsh Cancer Intelligence & Surveillance Unit, 14 Cathedral Road, Cardiff CF1 9LJ
Address correspondence to R. Roberts. E-mail: richard.roberts{at}nphsnorthwales.wales.nhs.uk
Background We investigated claims by a campaigning group of a cancer cluster associated with a local cement works.
Methods To investigate cancer rates in the town we defined the study area as the Census wards matching the geographical area code supplied to the campaigning group. Standard methods were applied to registered cases of cancer for the area for the years 19741989 to derive observed and expected numbers. The significance of the relative risk was assessed using the Poisson distribution. By selecting a different denominator population we attempted to reproduce the results of the campaign group. Cancer rates around the cement works were investigated for four cancer types plausibly associated with emissions, using cancer registrations for the years 19851994. Cases were mapped to 1981 Census ward boundaries, and the same statistical methods were used, but expected counts were also adjusted for deprivation. Rates were calculated for an inner 2 km zone and outer zone 25 km from the works. Relative risk was calculated and the ratio of risks was examined for evidence of increased risk closer to the works.
Results Relative risks were not significantly elevated either in the town or around the cement works itself. We were able to reproduce the likely errors that resulted in the elevated relative risks for five cancer groups claimed by the campaigning group.
Conclusions We found no evidence of increased incidence of cancer around the cement works. Incorrect handling of cancer registration data can result in spurious cancer clusters and unnecessary public alarm.
Keywords: MESH: environmental pollution, industry, small-area analysis, non-MESH: cement
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
C. Busby and V. Howard Fundamental errors in official epidemiological studies of environmental pollution in Wales J. Public Health Med., June 1, 2006; 28(2): 177 - 178. [Full Text] [PDF] |
||||
