Cancers are complex, arising from an accumulation of changes to DNA, often taking place over years or decades, which lead to altered cell function, unlimited growth and the spread of the disease. Many factors across our physical, biological and social environments drive these processes; from genetic inheritance and personal choices, to contact with pollution and microorganisms. Even the people we live with can make us more or less prone to disease. Scientists are working to map the web of environmental factors causing cancer in order to make better diagnoses, develop better treatments and inform public policy.

Some individuals and groups are more prone to certain diseases than others. Who is most at risk is not easy to spot in one study or one set of data as disease might be driven by many factors across the physical, biological and social environments. Combining and analysing large data sets from different sources — for example hospital records, genealogical information and genetic data — can reveal multi-factored connections that would otherwise be impossible to spot.

Scientists are gaining deeper insights into the many, often hidden, factors that cause disease. This work inevitably relies on data about individuals, which raises questions about privacy and consent.

Large-scale studies of diverse data could help reduce healthcare inequality. Some people have better access to healthcare than others due to a range of social and economic circumstances. Identifying more specific risk factors for ill health could help target resources at those most in need. It may also reduce the amount of invasive testing on low-risk groups.