We studied childhood cancer incidence in a population-based twin cohort usi
ng record linkage to the National Registry of Childhood Tumours, After corr
ecting far mortality, an incidence deficit was observed (Standardized incid
ence Ratio (SIR) 79; 95% Confidence Interval (CI) 39-120). Pooled analysis
with data from published cohort studies indicates a similar significant inc
idence reduction (SIR 81, 95% CI 67-96). Further studies are warranted. (C)
2001 Cancer Research Campaign.