The Guangzhou Cohort Study is a collaborative research project between The Universities of Birmingham and Hong Kong, and The Guangzhou Occupational Diseases Prevention and Treatment Centre in China. The study commenced in October 2003 and is recruiting men and women over the age of 50, from a city in southern China (Guangzhou) - a population that has undergone rapid economic transition. So far about 25,000 participants have been recruited, with plans for a final sample size of 40,000. Participants undergo detailed baseline characterization and phenotypic assessment, with storage of their genetic materials.