A Different View-Paternal Radiation Exposure and Stillbirths

["Roger P. Shaw" <rshaw@mccarter.com>]

An recent posting included a story from Reuters Health stating a link between paternal radiation exposure in the workplace and the incidence of stillbirths. The following may help to put the actual study in some perspective and maybe save some RADSAFERS some time as well. Presented here a two articles, the second one is from Reuters, and the first article previously posted which is specifically from Reuters Health (presumably by authored by different journalists). This also provides another good example of 'journalistic differences' that we so often see..

The principal problem is that the first article is incomplete and could easily cause concern for a given reader.  A close look at just the data presented actually shows the percent of stillbirths out of the total potential live births to be slightly lower for the radiation workers than for the general public (as pointed out in an earlier posting). There is no discussion of the difference in the incidence of stillbirths  for mothers having children at an increasingly older age within the general population. This has relevance, since the very few workers with the high doses referenced are usually older workers, presumably with wives that are generally older in age as well (obviously an assumption here). In both cases the number of people in the study lacks sufficient statistical power to draw any definitive conclusions, including one of association, not to mention causal relationship.

In my experience mainstream studies have not shown a relationship between radiation exposure to the father and increased incidence of stillbirths. There may be room for comment on this.

Note that a larger ongoing study mentioned, The Nuclear Industry Family Study, may provide more definitive results (BMJ Volume 318  29 MAY 1999, 1452-1454).



Paternal Radiation Exposure in The Workplace Linked to
Stillbirth in British Study

WESTPORT, Oct 27 (Reuters Health)- Men exposed to external radiation in the workplace, particularly in high doses, may be at increased risk of having a stillborn child, British researchers say in the October 23rd issue of The Lancet. 

However, this "...possible risk of stillbirth must be kept in perspective," Dr. Hazel Inskip, of the University of Southhampton, UK, cautions in an editorial elsewhere in the journal. 

Dr. Louise Parker, of the royal Victoria Infirmary in Newcastle upon Tyne, and colleagues linked birth registration data with information on radiation exposure for men employed at a nuclear reprocessing plant in Sellafield. Of nearly 250,000 livebirths and more than 3,700 stillbirths in the county of Cumbria between 1950 and 1989, approximately 9,000 livebirths and 130 stillbirths involved partners of men working at the plant. 

"Stillbirth risk was significantly associated with total external paternal preconception irradiation in both the cohort and case-control studies," the investigators report. Specifically, the risk of stillbirth increased 24% for each 100 mSv {10 rem} increase in the father's total exposure to external ionizing radiation before conception.

The association between paternal radiation exposure and stillbirth was greatest for stillbirths associated with birth defects, particularly neural-tube defects.

The new findings may "...come as a surprise to many," editorialist Dr. Inskip says, partly because many scientists have dismissed the possibility of a link between stillbirth and paternal radiation exposure due to insufficient evidence.

Dr. Inskip criticizes the British study for its size and lack of control for maternal factors associated with stillbirth, but acknowledges that the study does raise a few questions. In particular, the potential mechanism underlying the link reported by Dr. Parker and others remains uncertain.

Hopefully, the forthcoming results of the Nuclear Industry Family Study will resolve the debate about whether or not paternal exposure to external radiation causes stillbirth, and provide some insight into possible explanations for this relationship, the editorialist concludes. 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  _ _ 

Friday October 22 12:13 AM ET

Radiation Workers Don't Father More Stillborns

LONDON (Reuters) - Workers exposed to radiation are no more likely on the whole to father stillborn babies than other men, British researchers said Friday.

But the scientists who examined birth records and radiation levels of workers at a British nuclear reprocessing plant did say there was an increased risk of stillbirths that corresponded with cases of excessive radiation exposure.

``When we looked at the radiation effect, the risk of having a stillborn child does increase with increasing radiation exposure, but when that risk gets appreciable it's at a fairly high dose and there are relatively few people with that dose,'' Dr Louise Parker said in a telephone interview.

The epidemiologist and her colleagues at the Royal Victoria Infirmary in Newcastle-upon-Tyne, northern England, described it as a statistical association between radiation exposure and stillbirths. They said they could not say if it was causal.

``We, and hopefully other researchers elsewhere, need to go on and address the question about whether what we have found is reflecting causal association or not,'' Parker added.

The findings, which are reported in The Lancet medical journal, are based on a comparison of stillbirth records in the English county of Cumbria from 1950 to 1989 and a database of workers at Sellafield, a local nuclear reprocessing plant.

``Overall the current workforce would have very little excess risk. So I don't think the current workforce should be concerned on an individual basis,'' said Parker.

British Nuclear Fuels Plc (BNFL), which operates the Sellafield plant, welcomed the findings of the study.

``The statistical association which the study reports actually disappears altogether if just one single stillbirth case is removed. The findings could also be interpreted as arguing against any real effect for radiation,'' David Coulston, the plant's environment, health and safety director, said in a statement.

``It is important that nobody mistakenly interprets these findings as 'cause and effect','' he added.

The researchers identified 130 stillbirths and 9,078 live births fathered by employees at Sellafield. They examined company records for the lifetime radiation exposure of each worker and exposure in the 90 days before conception and compared them with matched controls.

Lancet 1999;354:1400-1401, 1407-1414.


Roger P. Shaw, CHP
McCarter & English, LLP
Four Gateway Center
100 Mulberry Street
Newark, NJ  08736
973.622.4444  


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