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DEN-GLO: Glostrup Contributors from the MPC: Carsten Agger and Torben Jørgensen

© National Institute for Health and Welfare and the MORGAM Project investigators Last updated: 22 June 2010 For more information, please contact Kari Kuulasmaa (firstname.lastname@thl.fi)

Contents

• Cohort identification
• Cohort recruitment and baseline examination
• End-points followed-up
• End of follow-up period
• Follow-up procedures
• Diagnostic procedures
  • at baseline
  • during follow-up
• References
• Updates

Cohort identification

• Country: Denmark
• MPC: 19 - Glostrup
  • Administrative centre: Research Centre for Prevention and Health, Glostrup, Denmark
  • Key personnel: Torben Jørgensen (Principal Investigator), Carsten Agger, Anders Borglykke
• RUs:
  • 01 - Glostrup. Eleven municipalities in the urban county Glostrup of Copenhagen city.
• RUAs:
  • DEN-GLOa
• Cohorts:
  • Cohort 01: Respondents of random samples of men and women of the RU, born in 1922, 1932, 1942 or 1952. The baseline survey was carried out in 1982-84 when the age of the persons was about 30, 40, 50 or 60 years.
  • Cohort 02: Respondents of random samples of the men and women of the RU, born in 1926, 1936, 1946 or 1956. The baseline survey was carried out in 1986-87 when the age of the persons was about 30, 40, 50 or 60 years.
  • Cohort 03: Respondents of random samples of the men and women of the RU, born in 1931, 1941, 1951 or 1961. The baseline survey was carried out in 1991-92 when the age of the persons was about 30, 40, 50 or 60 years.
  • Cohort 21: Respondents of a re-examination of Cohort 01. The re-examination, which is the baseline for this cohort, was carried out in 1993-94 when the age of the persons was about 41, 51, 61 or 71 years.

Cohort recruitment and baseline examination:

The cohorts were formed by the respondents of representative surveys of the RU. The national population register included in the Civil Registration System (CRS) was used as the sampling frame. Simple random sampling, stratified by sex and the year of birth, was used for Cohorts 01, 02 and 03. Cohort 21 consists of the respondents (70%) of a re-examination of Cohort 01. The baseline examinations of Cohorts 01, 02 and 03 were carried out as part of the WHO MONICA Project. The MONICA procedures were used also in Cohort 21.

The size of the MORGAM cohorts and response rates of the population surveys from which cohorts were derived are:

DNA are available for the members of Cohorts 03 and 21.

End-points followed up:

• Deaths: yes
• Non-fatal acute MI: yes
• Unstable angina pectoris: yes
• Silent MI: no
• Cardiac revascularization: no
• Stable angina pectoris: no
• Non-fatal stroke events: yes
• Thrombo-embolic events: yes

End of follow-up period:

• Fatal events:
  • 31 December 2000
  • In year 2006 the follow-up was extended to 31 December 2001
• Non-fatal events:
  • 31 December 2000
  • In year 2006 the follow-up was extended to 31 December 2001

Follow-up procedures

Sources of data

• Civil Registration System (CRS): The centralised civil register, administrated by the CRS Office of the Ministry of the Interior, was set up in 1968 on the basis of the previously manually compiled municipal registers. Everyone in Denmark is registered in the CRS. The system includes the information about the vital status of the individuals along with other information which can be retrieved using the personal identification number. Persons who emigrate will have a date of emigration registered in the CRS. If they return (immigrate) the date of immigration will be registered as well.
• Causes of Death Register: The Causes of Death Register maintained by the National Board of Health covers all deaths in Denmark. However, a death outside Denmark is not recorded if the person was emigrated, even he or she was still a citizen of Denmark. The Causes of death Register compiles the underlying cause of death using the information on the death certificate and the rules of the International Classification of Diseases (ICD) of the WHO. The eighth revision of ICD was used up to 1993 and the tenth revision since 1994. This register has been validated for coronary and stroke deaths using MONICA coronary and stroke event registers [1, 2].
• National Hospital Discharge Register: The National Board of Health keeps the National Patient Registry. Among other things, it includes the dates of the hospitalizations and ICD codes of clinical diagnoses assigned to the patients by the treating doctors. The register has covered the whole country since 1978 [3]. Assessments of the validity of the clinical diagnoses for coronary and stroke events can be found in references [1], [2] and [4].

Procedures

Everyone in Denmark has an unique personal identification number issued by the Civil Registration System (CRS). The cohorts were linked to the National Hospital Discharge Register, to the Causes of Death Register and to the Civil Registration System using the personal identification number. Therefore, the mortality and the morbidity follow-up covered the whole country. If a person moved out of the country, then he/she was lost to follow-up and the date of moving was recorded.

Diagnostic procedures

At baseline:

• History of MI:
  • Documented: data not available
  • Self-reported: An affirmative answer to an option "A myocardial infarction (thrombosis in the heart)" under the question "Have you ever been told by a doctor that you have had any of the following diseases?".
  • ECG: data not available
  • Rose questionnaire: As specified in item HISMI4 of MORGAM Form 21. Data not available for Cohort 01.
• History of cardiac revascularisation:
  • Documented: data not available
  • Self-reported: data not available
• History of angina pectoris:
  • Documented: data not available
  • Rose questionnaire: As specified in item HISAP2 of MORGAM Form 21. Data available for cohort 02 and 21.
  • Self-reported: data not available
• History of coronary heart disease, type unspecified: data not available
• History of stroke:
  • Documented: data not available
  • Self-reported: An affirmative answer to either or both of two options "Cerebral infarction (brain thrombosis)" and "Cerebral haemorrhage" under the question "Have you ever been told by a doctor that you have had any of the following diseases?".
• History of Diabetes: An affirmative answer to an option "Diabetes" under the question "Have you ever been told by a doctor that you have had any of the following diseases?".

During follow-up:

• Deaths: Final official cause of death codes from the Causes of Death Register were used for the relevant item of MORGAM Form 25.
• CHD events: For events found in the National Hospital Discharge Register the diagnostic classification was based on the ICD-codes:

  Hospital discharge code		MORGAM DGNCAT
  ICD-8	ICD-10
  410	I21, I22	3
  411	I20.0	4
  other		7

  For events found from in the Causes of Death Register, the diagnostic classification was based on the ICD-codes of the underlying and the immediate cause of death:

  Cause of death code		MORGAM DGNCAT
  ICD-8	ICD-10
  410-414	I20-I25	3
  795	I46, R96, R98, R99	5
  other		7

  Coronary events occurring within 28 days of each other were considered as one event. For events found both in the National Hospital Discharge Register and the Causes of Death Register, a coronary event diagnosis was given if it was found in either of them. If several diagnoses were given during a 28-days period the most severe event was used for the classification.

• Stroke events: For events found in the National Hospital Discharge Register the diagnostic classification was done using the ICD-codes :

  Hospital discharge code or cause of death code		MORGAM DGNCAT
  ICD-8	ICD-10
  430-434, 436	I60, I61, I63, I64,I69	9
  other		4

  For events found from the Causes of Death Register, the diagnostic classification using the ICD-codes of the underlying and the immediate cause of death:

  Cause of death code		MORGAM DGNCAT
  ICD-8	ICD-10
  430-434, 436	I60, I61, I63, I64, I69	9
  other		4

  Events occurring within 28 days of each other were considered as one event. For events found both in the Hospital Discharge register and the Register of Causes of Death, a stroke diagnosis was given if it was found in either of them.

• Thrombo-embolic events: For events found in the Causes of Death Register or in the National Hospital Discharge Register, the diagnostic classification was based on their ICD-codes:

  Hospital discharge or cause of death code		Type of venous thromboembolic event in MORGAM
  ICD-8	ICD-10
  450, 673.9	I26, O88.2	Pulmonary embolism
  451, 671	I80 (excl.I80.0), O87.1	Deep vein thrombosis
  other		not recorded as thromboembolic event in MORGAM

  Events occurring within 28 days of each other were considered as one event.

References

1. Kirchhoff M, Davidsen M, Brønnum-Hansen H, Hansen B, Schnack H, Eriksen LS, Madsen M, Schroll M. Incidence of myocardial infarction in the Danish MONICA population 1982-91. Int J Epidemiol. 1999;28:211-218.
2. Thorvaldsen P, Davidsen M, Brønnum-Hansen H, Schroll M, for the Danish MONICA study group. Stable stroke occurrence despite incidence reduction in an ageing population. Stroke trends in the Danish monitoring trends and determinants in cardiovascular disease (MONICA) population. Stroke. 1999;30:2529-34.
3. Jürgensen HL, Frølund C, Gustavsen J, Mosbech H, Guldhammer B, Mosbech J. Registration of diagnoses in the Danish National Registry of Patients. Methods Inf Med. 1986;25:158-64.
4. Madsen M, Davidsen M, Rasmussen S, Abildstrom SZ, Osler M. The validity of the diagnosis of acute myocardial infarction in routine statistics: a comparison of mortality and hospital discharge data with the Danish MONICA registry. J Clin Epidemiol. 2003 Feb;56(2):124-30.

Updates to this document

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