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First Publication Of Long-term Effects Of Participation In The Human Volunteer Programme At Porton Down

November 01, 2017

Two papers published this week in the British Medical Journal report results from an independent scientific study of death and cancer rates in veterans who took part in the Ministry of Defence's (MoD) Human Volunteer Programme (HVP) at Porton Down between 1941 and 1989. The Human Volunteer Programme tested the effects of exposure to chemical warfare agents on people, and the protective potential of respirators or clothing against these chemicals. This is the first time that information on the long-term health of veterans included in these tests has been assembled and published.

Over the course of study, 18,276 men were identified as having taken part in experimental tests at Porton Down and followed up for an average of 40 years between 1941 and 2004. Porton Down veterans (PDVs) were found to have a slightly higher death rate than a similar group of 17,600 veterans who did not participate. This increase was estimated to be 6% and is described as an excess of mortality. This means that 6% more men died over the course of the average 40 year follow up period in the PDV group than in the group of veterans who did not participate in the HVP.

No difference in rates of cancer between the two groups of veterans was found. Overall rates of death in each group of veterans were lower than in the general UK population; this is a common finding in occupational groups.

The MoD provided funding for the assembly, analysis and interpretation of data the study. The research team for the study was based at the University of Oxford and led by Oxford University academics Dr Katherine Venables and Dr Lucy Carpenter, with co-investigators from the University of London.

The MoD took advice on formulating the questions for the research team from the Medical Research Council which set up a liaison group independent of the MoD chaired by Professor Tom Meade of the London School of Hygiene and Tropical Medicine. This liaison group oversaw the progress of the research by having regular contact with the investigators.

This comprehensive study required assembly of data from three sources: the MoD historical archive held at Porton Down that contains details of the HVP, MoD personnel files held in military archives, and death certificates and cancer registration files held by the Office for National Statistics.

The study compared PDVs with a similar group of veterans who did not participate in the HVP; for the purposes of the study this group is known as the non-Porton Down veterans. In both groups identical health information was sought on each individual. This included whether a person had died or had been diagnosed with cancer during the follow-up period.

Overall twelve disease groups of cause of death were examined in the analysis. When compared to non-Porton Down veterans, there were more deaths among the PDVs attributed to infectious or parasitic diseases, genitourinary diseases, circulatory diseases, and external causes. In the PDV group there were also more deaths overseas.

The research team did not have access to information on potentially influential factors like whether or not veterans smoked or how long they spent in overseas postings. As a result, they could not attribute these findings, or the overall 6% increase in death rate, to participation in the HVP at Porton Down or to the effects of these other factors.

The research team used cancer registration records and entries for cancer on death certificates to determine rates of cancer in each group of veterans. Overall, the cancer rate was the same in Porton Down veterans and non-Porton Down veterans. However, cancers that could not be easily defined were more common in the Porton Down Veterans group.

Speaking about the results Dr Katherine Venables said:

''This is the first time that the long-term effects of participation by members of the armed forces in experimental tests at Porton Down has been studied. We aimed to include every veteran who participated in tests at Porton Down between the 1940s and the 1980s. This has enabled us to build as clear a picture as possible of the overall impact that taking part in tests at Porton Down has had on their long-term health.''

Co-investigator Dr Lucy Carpenter continued:

''What we have found is a small increase in overall death rates in the Porton Down veterans when compared with other veterans but no increase in overall cancer rates. Many of the Porton Down veterans have concerns about the effect that taking part in experimental tests will have had on their health. We hope the results of this independent study may help to answer some of their questions.''

Original research papers: Mortality of British military participants in human experimental research into chemical warfare agents at Porton Down: cohort study and Cancer morbidity in British military veterans included in chemical warfare agent experiments at Porton Down: cohort study are published in the British Medical Journal.

In a third paper which appeared recently the authors reported on the chemical tests that Porton Down veterans were exposed to. This paper "Exposures recorded for participants in the UK chemical warfare agents human research programme" was published in the Annals of Occupational Hygiene in January 2009.

The Ministry of Defence operates a freephone helpline for former participants in the Human Volunteer Programme to enable them or their representatives to obtain detailed information about the studies they took part in.

British Medical Journal