The rural/urban designation of population is embodied in "hukou", a residence registry system of thousand years' history, which required every person registers in the same place under his/her parents' residence.
The analytic variables included age at diagnosis, race/ethnicity, marital status, insurance, education, poverty, working class status, urban-rural residence, registry, whether the tumor was screen detected, digital rectal exam (DRE) results, PSA value, Gleason score, and Charlson comorbidity score.
Control individuals were selected using the Resident Registry of each city and were frequency matched on ethnicity, age (±5 years), and community of residence to the cases.
Sensitivity analyses were carried out to test that the census accurately reflected the birth cohort's place of residence, using birth registries for the whole 2003 year in Trent and from one of the districts in 1999 in Ile-de-France.
The manner in which this happens can be seen in sex offender registries and residence restrictions.
These mandatory registries capture residence and vital status of persons who e.g. moved to another city.
Residence and work permit registries represent another major sources of data on migration.
For the baseline survey, we obtain a random sample from the local registries of residence.
30 Urban/rural environment was assessed at baseline by retrieving data on place of residence from the population registry offices of the city and the 29 counties of Munich and was defined as either living in the city of Munich (10 559 people per km) or in the rural surroundings (1432 people per km) at baseline.
