The document discusses the research potential of using Sweden's unique personal identification number system and national health and social registers. It notes that researchers can access de-identified data from multiple linked registers to study topics like demographics, social factors, health outcomes, and family relationships across generations. Examples are provided of studies on leukemia risk in families and cancer transmission through blood transfusions.

1. Research possibilities with the Personal
Identification Number in Sweden
Marie Reilly
Department of Medical Epidemiology and Biostatistics,
Karolinska Institutet
PPI meeting, 22nd Sept 2013, Stockholm

2.  Personnummer (PN) is unique
 used in all contacts with the social and health system
 Routine data collection in national ”registers”, from birth to death
 Researchers can access the data registers
 Public trust
Reasons for research potential

3. 3
Information on individuals concerning:
Demographics:population: births, deaths, age, sex, place, migration
Social factors: Education, housing, work , crime...
Health: hospitalizations, outpatient, cancer, prescriptions, ...
Data gathered in Swedish registers
But also data allowing
families and households
to be identified

4. Multi-generation register
4
Allows us to identify children, parents, sisters, brothers,..
grandparents, aunts, uncles, cousins,step-families,...

5. Who takes care of the registers?
Data registers are managed by government authorities:
 population data by Statistics Sweden (SCB)
 health and social data by National Board of Health and Welfare
(Socialstyrelsen, ”sos”)
5

6. Health and social data registers (www.sos.se)
 Hälsodataregister
 Cancerregistret
 Kommunal hälso- och sjukvård till äldre och personer med
funktionsnedsättning
 Läkemedelsregistret
 Medicinska födelseregistret
 Patientregistret
 Tandhälsoregistret
 Socialtjänstregister
 Ekonomiskt bistånd
 Insatser enligt LSS
 Insatser för barn och unga
 Socialtjänstinsatser till äldre och personer med funktionsnedsättning
 Tvångsvård av vuxna missbrukare
6

7. Much valuable information for research
But how to protect the individual?
Registers are not open/unlocked for anyone to see!
Researchers :
must get ethical approval for proposed studies:
Justify what information needed
Explain how data will be protected
Data authorities:
almost always provide de-identified data
(PIN is replaced by an anonymous ”lopnummer”)
where information might reveal identity, data grouped
Person/Patient: can choose to not participate
7

8. Steps from research idea to results
8
Hypothesis Ethical
Application
Data
request
Data
cleaning
Data linkage
(PIN)
Data
analysis
Publication in scientific journals

9. Example: The risk of leukemia in families
9
Cancer
Register
• ICD codes
(Leukemia)
Total
Population
Register
• Emigration
immigration
dates
Census
• County of
residence
Multi-
generation
Register
1932~
1958~
Family
Structure
Number of cases in a family
1 2 3
21,811 143 2

10. 10

11. Example from blood transfusion
Research question:
Can cancer be transmitted from a donor to recipient?
In Sweden, donations not taken from cancer survivors
but we can address the question:
Does blood from a pre-cancerous donor put the transfusion
recipient at increased risk of cancer?
11

12. SCANDAT database
(Scandinavian Donation and Transfusion)
Person
Cancer
Variables
PID
Diagnosis date
Anatomical site
Basis for diagnosis
Morphology
Variables
PID (of mother)
Birth date
Pregnancy and
offspring information
Smoking/alcohol
Inpatient
Variables
PID
Entry/Exit date
Hospital, Department
Discharge diagnoses
Surgical procedures
Death
Variables
PID
Underlying cause
Contributory causes
Basis for diagnosis
Autopsy
Birth
Transfusion
Variables
PID
DID
BID
Transfusion date
Hospital
Component
Variables
DID
BID
Manufacturing date
Component type
Volume
Donation
Variables
PID
DID
Donation date
Hb value
Donation type
Variables
PID
Birth date
Sex
Blood group
Death date
Emigration date
DID BID
PIDPID
PID PID
DID

13. 13

14. 14

15. Numerous other applications:
15
Parents AgedAdultAdolescenceChildhoodPrenatal
Perinatal
Parents AgedAdultAdolescenceChildhoodPrenatal
Perinatal
Exposure
Outcome
Drug Prescription
Register (WP1)
Multigeneration Register (WP1-WP5)
Inpatient Register (WP1 and WP 3)
Medical Birth
Register (WP1
and WP3)
WP1
•Inpatient Register
(1964-)
•Outpatient Register
(2005-)
•Drug Prescription
Register (2005-)
•National Diabetes
Register (1996-)
WP2
•National Crime
Register (1973-)
WP3
•Conscript Register (1962-)
•Drug Prescription Register (2005-)
WP4
•Inpatient Register (1964-), Outpatient Register (2005-),
RiksSvikt (2003-), SWEDEHEART (1995-), Riks-Stroke
(1994-),Cause of Death Register (1952-)
WP5
•Swedish Cancer Register (1958-), Cause of Death
Register (1952-)
Register of Education (WP3-WP4)
Population and Housing Censuses 1960 -70 -80 -90 (WP3-WP4)

16. 16
Potential research question:
Does blood group predict personality?

17. What would you like to study?
17

18. Limitations of register data?
18