(October 29, 1999) A study on stillbirths among offspring of male radiation workers at Sellafield was published in The Lancet on October 22 1999. The study, part of a larger programme of work investigating the health of the children of the Sellafield workforce, set out to find whether there was evidence of an association between stillbirth risk and paternal exposure to ionising radiation.
(520.5103) CORE - As reported in The Lancet (Vol 354, No 9188, Article 1407), the study found that "a significant positive association was found between the risk of a baby being stillborn and the father's total exposure to external ionising radiation before conception. The risk was higher for stillbirths with congenital anomaly and was highest for the nine stillbirths with neural-tube defects".
The study ("Stillbirths among offspring of male radiation workers at Sellafield nuclear reprocessing plant", by Louise Parker, Mark.S. Pearce, Heather O Dickinson, Murray Aitken, Alan W Craft), the largest and most comprehensive investigation of transgenerational effects in any workforce occupationally exposed to ionising radiation, was undertaken by the Departments of Child Health and Statistics at Newcastle University and partly funded by BNFL.
The researchers studied the birth documents of 248097 livebirths and 3715 stillbirths registered in Cumbria between 1950 and 1989, and identified 9078 livebirths and 130 stillbirths to wives and partners of male radiation workers at Sellafield. Preconceptional radiation doses to Sellafield fathers were estimated from annual external dose summaries, including film badge records, and from routine (urinary) internal dose assessments. Doses in the 90 days before conception were estimated pro-rata from annual dose summaries. The study found there was a significant positive association - up to 3 times - between both the annual and 90-day doses and stillbirth risk.
Recognising the small numbers of stillbirths involved, the authors point out that the adjusted odds ratio per 100 mSv was significantly raised for all stillbirths after 1961 for which cause of death was available. For the 15 stillbirths with congenital anomaly (9 neural-tube defects, 3 hydrocephalus, 1 Down's syndrome, 1 multiple anomaly, 1 trisomy not otherwise specified) and, within this category, for those with neural- tube defects (8 anencephalic, 1 spina bifida), the odds ratio was significantly raised.
In the discussion section of the study, the authors state that "stillbirth risk was significantly associated with total external paternal preconceptional irradiation in both the cohort and case- control studies", that "one possible explanation of our findings is that irradiation caused genetic damage to the father's germ cells". The authors could find no association with internal radiation dose or to any individual radionuclide. The study showed a reduction in stillbirth rate from 25.9 per 1000 between 1950-1959, and 6.2 per 1000 between 1980-1989.
In their response to the study, BNFL have assured the Sellafield workforce (previously briefed by the study's authors on October 15) that the stillbirths study was "absolutely no cause for concern".
Admitting to the statistical association between total radiation exposure and stillbirth rate, the Company draws on the authors presentation to the workforce that no one should change any plans for having a family and that there was no (causal) proof that radiation had played a part in the statistical association found. As confirmation of the Company's view, BNFL had solicited supporting statements from "world experts" (some of whom have close links to BNFL either as court witnesses or having received research funding in the past). In a summary of their own views, and those of the experts, that radiation was not to blame, BNFL point out that stillbirths are overwhelmingly caused by factors associated with the mother, including age, diet and level of smoking.
Source: CORE Briefing 20/99, 26 October 1999
Contact: Cumbrians Opposed to a Radioactive Environment,
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