This study provides an overview of the representativeness of the UK Biobank cohort with regard to a variety of key characteristics in comparison with the general UK population using data from nationally representative surveys. We expect that these findings will be used by researchers to inform the interpretation of results or, in some instances, to help generate weighted results (e.g., in order to estimate nationally representative disease rates). We were able to compare participation rates for key sociodemographic characteristics (such as age, sex, socioeconomic status, and geographic location) due to the availability of such data for the total sampling frame. The availability of follow-up health data enabled us to compare death and cancer incidence rates with age- and sex-specific national rates, and the large size of the cohort meant that sufficient numbers of cases had accrued to investigate common cancer types. All UK Biobank participants are flagged by national death and cancer registries, and loss to follow-up due to emigration has been minimal (0.3% of the cohort). Further follow-up is required to determine whether this “healthy volunteer effect” attenuates over
