Early life exposures and cancer risk: systematic literature reviews

Evaluating how different early life stages influence cancer risk, including identification of critical age windows that may be particularly amenable to lifestyle interventions

The aim of the Global Cancer Update Programme (CUP Global), formerly known as the World Cancer Research Fund/American Institute for Cancer Research Continuous Update Project, is to regularly review the epidemiological evidence on the role of diet, nutrition, body fatness, and physical activity on cancer risk and survival, by conducting systematic literature reviews and meta-analyses. In 2018, the Third Expert Report was released along with ten updated WCRF/AICR Cancer Prevention Recommendations, which provides authoritative expert guidance on how best to reduce risk of cancer and improve outcomes after a diagnosis.

Previous CUP work touched on the fact that different life stages could influence cancer risk, but did not explicitly seek to gather data on early life exposures and cancer risk. It was therefore not possible to explore in detail the impact of critical age windows earlier in life that may be amenable to lifestyle interventions. As part of CUP Global a better understanding of the impact of specific exposures on cancer risk will significantly enhance the evidence base, potentially allowing for the development of more tailored recommendations across age-groups.

The work involves developing a protocol and applying this to systematic literature reviews of diet, nutrition, body fatness, and physical activity exposures from preconception to age 30 years in relation to three of the most common cancers (breast, colorectal, and prostate cancer). Meta-analyses will be performed to pool effect estimates by pre-specified age groups: intrauterine life (from conception until birth), infancy (from birth up to 2 years), childhood (from 2 up to <10 years), adolescence (from 10 up to <20 years), and young adulthood (from 20 up to 30 years).

This work comprises a commissioned research project carried out by Dr Dieuwertje Kok and Dr Fränzel van Duijnhoven (co-PIs) and Dr Moniek van Zutphen (postdoc), from Wageningen University & Research in the Netherlands, collaborating with the CUP Global team at Imperial College London (UK) and the International Agency for Research on Cancer (France).