A community-based cohort study comprised of 500,000 volunteers aged between 40-69 years in 2006-2010 from across the United Kingdom. Participants have undergone measures, provided blood, urine and saliva samples, detailed information about themselves and agreed to have their health followed. The study aims to improve the prevention, diagnosis and treatment of a wide range of serious and life-threatening illnesses including cancer, heart disease, stroke, diabetes, arthritis, osteoporosis, eye disorders, depression and forms of dementia.