[ RadSafe ] Paper mortality rates of childhood leukaemia in proximity to nuclear facilities

[Fred Dawson]

European Journal of Cancer Care

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2354.2007.00679.x

Volume 16 Issue 4 Page 355-363, July 2007 

To cite this article: P.J. BAKER PHD, D.G. HOEL PHD (2007) 

Meta-analysis of standardized incidence and mortality rates of childhood
leukaemia in proximity to nuclear facilities 

European Journal of Cancer Care 16 (4), 355-363. 

doi:10.1111/j.1365-2354.2007.00679.x 
Abstract
Original article

Meta-analysis of standardized incidence and mortality rates of childhood
leukaemia in proximity to nuclear facilities
. P.J. BAKER, PHD11Research Analyst, Department of Biostatistics,
Biostatistics and Epidemiology, Medical University of South Carolina, Gulph
Mills, PA and Senior Project Statistician, Omnicare Clinical Research, Peter
J. Baker, Department of Biometry and Epidemiology at the Medical University
of South Carolina, 933 Mayberry Road, Gulph Mills, PA 19428, USA (E-mail:
pjbaker at alumni.musc.edu). & 
. D.G. HOEL, PHD22Professor, Department of Biostatistics, Biostatistics and
Epidemiology, Medical University of South Carolina, Charleston, SC, USA 
. 1Research Analyst, Department of Biostatistics, Biostatistics and
Epidemiology, Medical University of South Carolina, Gulph Mills, PA and
Senior Project Statistician, Omnicare Clinical Research, 2Professor,
Department of Biostatistics, Biostatistics and Epidemiology, Medical
University of South Carolina, Charleston, SC, USA
Peter J. Baker, Department of Biometry and Epidemiology at the Medical
University of South Carolina, 933 Mayberry Road, Gulph Mills, PA 19428, USA
(E-mail: pjbaker at alumni.musc.edu). 
BAKER P.J. & HOEL D.G. (2007) European Journal of Cancer Care 16, 355-363
Meta-analysis of standardized incidence and mortality rates of childhood
leukaemia in proximity to nuclear facilities 

Abstract
The meta-analysis combined and statistically analysed studies of childhood
leukaemia and nuclear facilities. Focus was on studies that calculated
standardized rates for individual facilities. Due to variability between
study designs, eight separate analyses were performed stratified by age and
zone. One hundred and thirty-six sites were used in at least one analysis.
Unadjusted, fixed effects and random effects models were used. Meta-rates
greater than one were found in all models at all stratification levels often
achieving statistical significance. Caution must be used when interpreting
these results. The meta-analysis was able to show an increase in childhood
leukaemia near nuclear facilities, but does not support a hypothesis to
explain the excess. Each type of model utilized has limitations. Fixed
effects models give greater weight to larger studies; however, population
density may be a risk factor. Random effects models give greater weight to
smaller studies that may be more likely to be affected by publication bias.
A limitation of the overall study design is that standardized rates must be
available for individual sites which led to exclusion of studies that only
calculated rates for multiple sites and those that presented other
statistical methods. Further, dose-response studies do not support excess
rates found near nuclear facilities. However, it cannot be ignored that the
majority of studies have found elevated rates, although not usually
statistically significant.


Fred Dawson
New Malden
England