Reported influenza in pregnancy and childhood tumour.

The present study was conducted to test the hypothesis that exposure to influenza in pregnancy increases the risk of tumour of certain type in childhood. Children ages 17 years or less diagnosed in Greece with brain tumours or neuroblastomas from 1982 to 1993 (n = 94) were contrasted to 210 controls selected from the same hospitals. Mothers of these children were interviewed about a variety of possible etiologic factors. The prevalence of influenza in Greece for each year during the period 1984-1992 was also compared with the number of children born during the same year who subsequently developed brain tumour or neuroblastoma. The results indicate a significant association between influenza in pregnant women and occurrence of tumour in index child (OR: 3.15, 95% CI: 1.13-8.77). These results persisted when adjustment for potential confounding factors was made. The findings should be interpreted cautiously because of lack of serologic documentation of information about infection obtained in interviews. A positive correlation (r = 0.74) of the number of tumour births by year of birth with the prevalence of influenza during the same year was also noted. This exploratory study is one of the few case-control studies of the epidemiology of childhood tumours in children, and the results suggest directions for future epidemiologic studies in this relatively uncharted field.