Table 1.

Data sources

Data source	Years	Variables
Total Population Register	1987–1991	Age, sex, marital status, family size, region of residence, year of arrival, region of origin, neighborhood deprivation
Inpatient hospital register	1987–2010	Diagnostic codes and dates
Outpatient register	2001–2010	Diagnostic codes and dates
Prescription drug register	2005–2010	Prescriptions filled of insulin (analogs) and antidiabetic agents

Note: Inpatient register data prior to 2001 were only used to exclude pre-existing cases of type 2 diabetes.