This post refers to the two papers: Cardis et al, 2005, Cardis et al, 2007:
1. Risk of cancer after low doses of ionising radiation: retrospective cohort study in 15 countries. Cardis E, et al. BMJ. 2005 Jul 9;331(7508):77.
2. The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry: estimates of radiation-related cancer risks, Cardis E, et al. , Radiat. Res., 167 (2007), pp. 396–416
These two papers are from a study of radiation workers from 15 countries that showed a slightly increased risk of cancer among the workers. The data is of questionable significance as seen in this graph from (Cardis 2005) showing the data for individual countries’ cancer risks (with more than 100 cancer deaths):
In the text, the paper said on p. 4, if Canadian data were excluded, there was no significant excess risk of cancers in the radiation workers:
In June 2011, Canadian Nuclear Safety Commission withdrew Canadian radiation worker data from use, citing problems with the data, and CNSC have stated that the Canadian data do not show an increased risk of cancer among the radiation workers (CNSC, 2011). Quotation from the report:
Conclusions of CNSC Report INFO-0811:
With the Canadian data removed, the Cardis data would no longer show increased risk of cancer for low dose radiation.
Since this is a major reversal of conclusion, is it not the responsibility of the authors of the Cardis study to publish a retraction or an erratum indicating the changed conclusion? The CNSC report is available online, but is not published, and is not well known, and so the Cardis 2005 and Cardis 2007 papers continues to be referenced to justify statements of increased risk of cancer from low dose radiation, as seen below:
(Smith et al., 2013) quote Cardis 2005 paper thus:
(Nayar et al., 2013) quote Cardis 2005 paper thus:
(Mathews et al., 2013) quote Cardis paper:
(Albert, 2013) quote Cardis 2005 paper – this paper just appeared on July 1, 2013:
(Pernot et al., 2012) - References Cardis 2007 paper as [4]. Please note E. Cardis is a co-author in this paper.
Thus, the misinformation regarding low dose radiation cancer risk among radiation workers continues to be spread, even though the results of the 15-country study have been discredited.
References:
CNSC. 2011. Verifying Canadian Nuclear Energy Worker Radiation Risk: A Reanalysis of Cancer Mortality in Canadian Nuclear Energy Workers (1957-1994) Summary Report, Canadian Nuclear Safety Commission. [Online]. Available: http://nuclearsafety.gc.ca/
