The detailed, standardized evaluation of dietary and lifestyle factors on a Europe-wide scale, including assessment of nutritional biomarkers in addition to dietary self-report, optimisation of dietary data through calibration, and validation of physical activity questionnaires against objective measures, will help to address questions that have not been resolved due to inconclusive results from earlier prospective studies or intervention trials. The study of different European populations with considerable heterogeneity in dietary habits and health behaviours will increase the generalisability of any potential findings. Heterogeneity in the confounding structure across countries will help to minimise the identification of false positive, non-causal associations. The large number of cases in InterAct will be instrumental in being able to investigate dose-response effects of important exposures in more detail and inform decisions about appropriate thresholds with greater precision of estimates.
