Childhood Cancer (Hansard, 18 May 1993)

§ Mr. Sackville

The committee's broad conclusion was to agree, with the authors of the study that parental employment in the nuclear industry could not account for the excess incidence of childhood leukaemia observed in the area.

The full text of the advice is as follows.

Statement from COMARE regarding the Aldermaston and Burghfield Case-control Report

1. The COMARE third report "On the incidence of Childhood Cancer in the West Berkshire and North Hampshire area, in which are situated the Atomic Weapons Research Establishment, Aldermaston and the Royal Ordnance Factory, Burghfield", concluded that:

there is a small but statistically significant increase in registration rates of childhood leukaemia in the age group 0–14 over the period 1972–85, in the areas within 10km of AWRE Aldermaston and ROF Burghfield, compared with both the national rates, and the regional rates of Oxford and Wessex.To investigate whether this increased childhood leukaemia incidence was related to parents' employment in the nuclear industry, COMARE recommended that a case-control study be undertaken. Government accepted the recommendation and the Department of Health provided funding for the work to be undertaken by the Imperial Cancer Research Fund Epidemiology Unit. The results of this "Case control study of leukaemia and non-Hodgkin's lymphoma among children aged 0–4 years living in West Berkshire and North Hampshire Health Districts" have now been published (British Medical Journal 1993 Vol. 306 pages 615–621) and considered by COMARE.2. The subjects were 54 children aged 0–4 years who had leukaemia or non-Hodgkins lymphoma diagnosed during 1972–89 who were horn in the study area and were resident there when the cancer was diagnosed. They were compared with six controls selected for each case. Five of the fifty four cases and fourteen out of the 324 controls had fathers or mothers or both who had been employed by the nuclear industry, a difference which was not significant. The main finding of the study was that three fathers of cases and two fathers of controls (and no mothers of either) had undertaken work which required radiation monitoring at some time (but in no instance in the 4 years immediately preceding) the conception of the child.

3. The study concluded that:

These results suggest that the children of fathers who had been monitored for exposure to external penetrating ionising radiation in the nuclear industry may be at increased risk of developing leukaemia before their fifth birthday. The finding is based on small numbers and could be due to chance.If the relationship is real the mechanisms are far From clear, except that the effect is unlikely to be due to external radiation; the possibility that it could be due to internal contamination by radioactive substances or some other exposure at work should be pursued. The above average rates of leukaemia in the study area cannot be accounted for by these findings.4. COMA RE welcomed the study. It was agreed that the study design, which had been commissioned to determine whether there was an association between childhood cancer and parental employment in the nuclear establishments of the study area, adequately addressed its aims in terms of subject, disease and control selection and methods of data collection and analysis. The stated conclusions were accepted by the Committee.5. The Committee noted that whereas their third report had found 53 cases of childhood leukaemia in the age group 0–4 years in the study area when only 34 would have been 150W expected on the basis of national rates, the current study had identified only 5 cases that could have been at any possible risk because a parent had worked in the nuclear industry. The Committee, after taking into account the different time periods considered by COMARE's third report and the current study, therefore agreed with the authors that employment in the nuclear industry of the parents of cases could not account for the excess incidence of childhood leukaemia observed in the area.6. COMARE noted the authors statement "our results can be interpreted as supporting Gardner and colleagues' finding" that the children of men who had been exposed to external penetrating ionising radiation before their child was conceived were at an increased risk of leukaemia. The Committee did not feel that conclusions regarding pre- and post-contraception exposure could be drawn from this study in view of the very small number of families affected. Furthermore it was agreed that the study provided no new evidence to distinguish between the various hypotheses previously suggested regarding causative agents or chance effects in relation to childhood cancer incidence in the vicinity of certain nuclear installations.7. COMARE noted that further studies of the occupational histories of the parents are currently being undertaken. The Committee considered that the further work proposed in the conclusion of the study was already being conducted in two studies now in progress. The first of these is the Nuclear Industries Family Study being undertaken by the Imperial Cancer Research Fund and the London School of Hygiene and Tropical Medicine and jointly funded by the Department of Health and the Health and Safety Executive. The second study, involving the National Radiological Protection Board and the Department of Public Health and Epidemiology at Birmingham University, will analyse the relationship between records of the National Register of Radiation Workers and those of the Childhood Cancer Registry Group.