Parental occupation in farming and childhood cancer risk in I4C

1. Parental occupation in farming andchildhood cancer risk in I4C Ann Olsson & Joachim Schüz

2. Rational • Majority of case-control studies show an association • Stronger associations with indoor pesticide exposure • Internal inconsistencies, e.g. lack of dose-response • Few cohorts show no or weaker association Case-control studies are prone to bias!

3. Information bias Recall differences regarding maternaloccupational exposureto pesticides prior to conception Years between the date of birth and the date of the interview  cases  controls [Schüz et al., Am J Epi, 2003]

4. Selection bias Typical pattern: Social gradient among controls [Law, Br J Cancer, 2002]

5. I4Cfarm • Design: Pool prospective cohorts • Benefits: • Data collected prior to diagnosis • Data collected closer after occurrence • Increased power to study “rare events”

6. Farming around the world Proportion of workersemployed in agriculture Global pesticide production

7. I4Cfarm - objectives • Investigate if parental occupations in different types of farming is associated with increased risk of cancer in their offspring • Evaluate the risk of childhood cancer associated with self reported parental use of pesticides during pregnancy • Compare type and frequency reported in case-control studies • If possible assess whether the risk of childhood cancer associated with parental exposure to occupation as a farmer and pesticides vary by exposure time-windows (preconception, prenatal, and postnatal)

8. I4Cfarm – study team • IARC (Ann Olsson, Joachim Schüz, Kurt Straif) • INSERM (Jacqueline Clavel) • MCRI (Gabriella Tikellis) • NCI (Martha Linet) • CREAL (Martine Vrijheid) • Eligible cohorts (PI’s) • MoBa, DNBC, ALSPAC, THIS, ?...

9. Eligible I4C cohorts so far…

10. Next steps • Eligibility of further cohorts? • Transfer of data to MCRI (Gabriella) • Harmonization of disease data (Martha) and occupational data (Ann & Martine) • Data analyses (at IARC) • Manuscripts (Study team)