Every ~5 years, a representative sample of surviving participants is invited for resurvey, with repeat interview, physical measurements and collection of biological samples. The resurveys will allow adjustment for “regression dilution” bias in the prospective analysis of associations of long-term “usual” levels of particular risk factors with diseases. The first resurvey was completed in October 2008, involving about 20,000 participants (~80% attendance). Apart from a few additional questions (e.g. recent hospitalisations), the data collection and survey procedures were much the same as in the baseline survey. The second resurvey was conducted during 2013-14. This included new and more detailed data collection, with additional questionnaire items on diet and physical activity, clinical enhancements (12-lead ECG, carotid IMT, ankle blood pressure, hand grip strength, heel bone mineral density and pulse wave velocity), urine sample collection and on-site testing, and blood cholesterol on-site testing.