Cancer in children of nuclear industry employees: report on children aged under 25 years from nuclear industry family study

Objective. To determine whether children of men and women occupationally ex posed to ionising radiation are at increased risk of developing leukaemia o r other cancers before their 25th birthday. Design. Cohort study of children of nuclear industry employees. Setting. Nuclear establishments operated by the Atomic Energy Authority, At omic Weapons Establishment, and British Nuclear Fuels. Subjects. 39557 children of male employees and 8883 children of female empl oyees. Main outcome measures. Cancer incidence in offspring reported by parents. E mployment and radiation monitoring data (including annual external dose) su pplied by the nuclear authorities. Results. 111 cancers were reported, of which 28 were leukaemia. The estimat ed standardised incidence ratios for children of male and female employees who were born in 1965 or later were 98 (95% confidence interval 73 to 129) and 96 (50 to 168) for all malignancies and 109 (61 to 180) and 95 (20 to 2 77) for leukaemia. The leukaemia rate in children whose fathers had accumul ated a preconceptual dose of greater than or equal to 100 mSv was 5.8 times that in children conceived before their fathers' employment in the nuclear industry (95% confidence interval 1.3 to 24.8) but this was based on only three exposed cases. Two of these cases were included in the west Cumbrian ("Gardner") case-control study. No significant treads were found between in creasing dose and leukaemia. Conclusions. Cancer in young people is rare, and our results are based on s mall numbers of events. Overall, the findings suggest that the incidence of cancer and leukaemia among children of nuclear industry employees is simil ar to that in the general population. The possibility that exposure of fath ers to relatively high doses of ionising radiation before their child's con ception might be related to an increased risk of leukaemia in their offspri ng could not be disproved, but this result was based on only three cases, t wo of which have been previously reported. High conceptual doses are rare, and even if the occupational association were causal, the number of leukaem ias involved would be small; in this study of over 46000 children, fewer th an three leukaemias could potentially be attributed to such an exposure.