In 2013, the British Journal of Cancer published an article (Bithell et al, 2013) (for references see below) purporting to show there were no leukemia increases in young children near UK nuclear power plants (NPPs). I published a post criticising this article stating that it should not have been published. The BJC has now printed a similar article (Bunch et al, 2014) which, if anything, is even worse than the 2013 one. The new article also should never have been published.
The new report concludes, first, that children, teenagers and young adults currently living close to Sellafield and Dounreay are not at an increased risk of developing cancer. Second, it concludes there is no evidence of any increased cancer risk later in life among those resident in these areas at birth.
However a close reading of the actual data in the report’s table 3 in fact reveals statistically significant cancer increases measured across all years and ages. The data layout in their table 3 carefully hides these increases so the data are more clearly laid out below (for Seascale ward), together with p values kindly added by Dr Alfred Körblein.
The very low p values in Seascale ward show that the cancer increases there are statistically significant, ie are not due to chance. It is notable that these increases and their accompanying p values are NOT discussed in the new report.
Total leukaemias (0-24 y)
|Obs||Exp||SIR||P value*||RR||P value**|
All malignancies (0-24 y)
|Obs||Exp||SIR||P value*||RR||P value**|
Obs= observed, Exp= expected, SIR= standardised incidence ratio, RR= relative risk
*one-sided P value (Poisson test), **one-sided P value (Binomial test) both calculated by Dr Alfred Körblein
So, at Seascale, the leukemia risk is 7.4-times greater than the control area (RR=7.4, P=0.0002), and for all malignancies, the risk is 3.3 times greater than the control area (RR= 3.3, P=0.0005).
The new article should therefore have reported that statistically significant cancer increases occurred across all ages and cancers in Seascale, about 4 km from Sellafield. Instead, the printed conclusions refrain from this and make misleading inferences in selected analyses which appear to show the opposite. This is poor science.
Let’s unpack that first conclusion that “children, teenagers and young adults currently living near Sellafield are not at an increased risk of developing cancer”. This is presumably based on the most recent data (1991-2006) which show 1 observed case (0-14 yr olds) and 1 observed case (15-24 yr olds). In fact, these are increases over the expected numbers, but you can’t say anything definite one way or the other as the numbers are far too small for meaningful conclusions. Also these data are now eight years old: can we really say that young people currently living near Sellafield are not running risks?
Let’s unpack the second conclusion that “there is no evidence of any increased cancer risk later in life among those resident in these areas at birth”. This is presumably based on the data for those aged 15-24, but in fact, these again show actual increases (Observed 4, Expected 1.43 for all cases). Again you can’t be definite from such small numbers as the increases are still not statistically significant, but to say there was no increased risk when in fact the numbers show the opposite is perverse and misleading.
Given the lack of statistical power in their chosen analyses and given the fact that increases were actually found, the report should not have concluded that people were not at risk. Instead it should have reported the cancer increases but added that the results of its chosen analyses were not statistically significant as they were underpowered. However, it should also have added that, over all cancers and all years, the observed cancer increases in fact were highly statistically significant.
There is a second major flaw in this study. Leukemia incidences vary a great deal depending on age at detection. Grouping babies and infants with other ages may mask increases among them, as any increase could be diluted by the numbers at older ages. This problem is well known and it’s for this reason that almost all studies in this area have focussed on under 5 year olds. This study should have done the same: it didn’t.
Another problem is that the leukemia data from 1963 to 1990 at Seascale only shows 5 cases. But the famous study by Gardner et al (1990) revealed 10 such cases. Where have the other 5 cases gone? Were they all detected before 1963?
Fourth, the study refrains from discussing the huge amount of evidence world-wide on childhood leukemias near NPPs as discussed by myself (Fairlie, 2013) and many others. It hardly mentions the important German KiKK study (Kaatsch et al, 2008) and ignores the meta-analysis of four European studies by Körblein and Fairlie (2012) which conclusively showed increased leukemia risks among under fives, living within five km of almost all NPPs in France, Germany, Switzerland and the UK.
In sum, like the similar study of leukemias the BJC published in 2013, this study should also not have been published as it is misleading and contains no scientifically useful information.
(PS This post concentrates on Sellafield but similar considerations and criticisms apply to the Dounreay data.)
I wish to thank Dr Körblein for his invaluable help in writing this post.
Bithell JF, M F G Murphy, C A Stiller, E Toumpakari, T Vincent and R Wakeford. (2013) Leukaemia in young children in the vicinity of British nuclear power plants: a case–control study. Br J Cancer. advance online publication, September 12, 2013; doi:10.1038/bjc.2013.560.
Bunch KJ, T J Vincent1, R J Black, M S Pearce, R J Q McNally, P A McKinney, L Parker, A W Craft and M F G Murphy (2014) Updated investigations of cancer excesses in individuals born or resident in the vicinity of Sellafield and Dounreay. British Journal of Cancer (2014), 1–10 | doi: 10.1038/bjc.2014.357
Fairlie I (2013) A hypothesis to explain childhood cancers near nuclear power plants. Journal of Environmental Radioactivity 133 (2014) 10e17
Gardner MJ, Snee MP; Hall AJ; Powell CA; Downes S; Terrell JD (1990) Results of case-control study of leukaemia and lymphoma among young people near Sellafield nuclear plant in West Cumbria. BMJ. 1990;300:423–429.
Kaatsch P, Spix C, Schulze-Rath R, Schmiedel S, Blettner M. (2008) Leukaemia in young children living in the vicinity of German nuclear power plants. Int J Cancer; 122: 721-726.
Körblein A and Fairlie I (2012) French Geocap study confirms increased leukemia risks in young children near nuclear power plants. Int J Cancer 131: 2970–2971.