5764 men and women in Iceland, aged 66 to 96 years entered the Ages Gene/Environment Susceptibility (AGES) - Reykjavik Study. Serum 25(OH)D was measured in 5,519 of all 5,764 (96%) participants at study entry in year 2002 through 2006. The main emphasis was on exploring whether pre-diagnostic serum levels of 25(OH)D were associated with survival after cancer diagnosis.