Table 1.

The National Registers Providing Data for the Study and the Covered Time Period

Danish Civil Registration System (DCRS): 1974–2010  • Identification of the unique personal identification (ID) number as a key identifier of all live-born children in Denmark between January 1, 1990 and December 31, 1999 • Identification of both parents of children in this cohort	Danish National Hospital Register (DNHR): 1980–2010  • ID number  • Lifetime ICD-10 cardiovascular diseases (I00-I99) from all inpatient admissions (since 1980) and outpatient contacts (since 1995) for all children in the cohort and their parents • Holds information on ICD-10 diagnoses, the date of admission, date of discharge, and ID of the hospital
Danish Psychiatric Central Register (DPCR): 1960–2010  • ID number  • Lifetime ICD-10 psychiatric diagnoses from all inpatient admissions (since 1960) and outpatient contacts (since 1995) of all children in the cohort and their parents • Information on date of admission, date of discharge, identification of the hospital, ICD-10 diagnoses, and conditions of admission (voluntary or coercive) for all contacts	Danish Register of Medical Product Statistics (DRMPS): 1995–2008  • ID number for each prescription  • All prescriptions for all children in the cohort and their parents • Information on the anatomical therapeutic chemical (ATC-code), the date of purchase, defined daily doses (DDD), and brand name
Integrated Database for Longitudinal Labour Market Research (IDA): 1980–2010  • ID number  • Age of mother and father  • Level and length of education of mother and father  • Parental employment status of mother and father on November 1 for each calendar year • Length of unemployment periods for mothers and fathers during each calendar year • Gross income of both parents for each calendar year	We included the following ATC-codes for stimulants treatment:  • Amphetamine (N06BA01)  • Dexamphetamine (N06BA02)  • Methylphenidate (N06BA04)
Danish Medical Birth Register (MBR): 1973–2010  • ID number  • Apgar score  • Birth weight  • Birth complications  • Maternal smoking during pregnancy	Cardiovascular risk factors, either in the child or in one of the parents:  • Any cardiovascular disease in parents (I00–I99)  • Any respiratory disease in parents (J00–J99)  • Congenital cardiovascular disease (Q20–28)  • Any cardiovascular disease in the child before the age of 5  • Fragile X (Q99.2)  • Down syndrome (Q90.x)  • Diabetes (E10–14)  • Cardiovascular medication (ATC-C code)  • Respiratory medication (ATC-R ode)  • Neuroleptics (ATC-N05A code)

ICD 10, International Statistical Classification of Diseases and Related Health Problems, 10th revision.