Objectives: To present details of the Norwegian Family Based Life Course Study.
Methods: All Norwegians participating in censuses from 1960 to 2001 were included. In addition to the personal identity number, we used household and family information from the 1960 census to link family members together. The NFLC study is further linked to other health registers and surveys.
Results: The proportion included and alive in 1960 increased from 67 % among those born in 1900 to more than 90 % for those born after 1940. In all, 5,266,270 were included. This combined family linkage approach gave 85 % parental linkage for those born in 1940 that dropped to 20 % of those born in 1930. The proportion with misclassified parents was less than 0.5 %. In all, 3,564,582 individuals were linked to their parents.
Conclusions: The NFLC is one of the largest follow-up of individuals over several decades in their life course. The comprehensive multigenerational, family linkage within the database contributes to large-scale use of various designs for investigating life course determinants.