The Copenhagen City Heart Study is an ongoing cardiovascular population study initiated in 1976 which has examined approximately 25,000 individuals from the general population. The initial sample has been re-invited up to four times and supplemented by younger individuals. The study includes questionnaires, clinical assessment and biomarkers. The population have been followed in a number of outcome registries and more than 900 scientific papers have been published.

The Copenhagen City Heart Study, also known as "Østerbroundersøgelsen", is a large prospective cardio-vascular population study of 20,000 women and men that was launched in 1975 by Dr Peter Schnohr and Dr Gorm Jensen together with statistician Jørgen Nyboe and Prof. A. Tybjærg Hansen.

The original purpose of the study was to focus on prevention of coronary heart disease and stroke. During the years many other aspects have been added to the study: pulmonary diseases, heart failure, arrhythmia, alcohol, arthrosis, eye diseases, allergy, epilepsia, dementia, stress, vital exhaustion, social network, sleep-apnoe, ageing and genetics. In the fourth and fifth wave of the examination echocardiography was included.

The Copenhagen City Heart Study has invited a random sample of the census population in an area of central Copenhagen in five waves. The primary population was a random sample of 19,329 men and women 20-93 years old, drawn from a population of approximately 90,000 inhabitants aged 20 years or older living in a central part of Copenhagen (Østerbro). Using the unique personal identification number (Central-Personal-Register-code), consisting of date of birth and a registration number, the sample was age-stratified within 5-year age groups, with the main emphasis on the age groups from 35 to 70 years. The total number of participants invited to the first four examinations was: 19,329+500+3,000+1,062 = 23,891 men and women. Of the original 14,223 examined at the first examination 3,092 (21.7%) have been examined in all four examinations.

Follow-up of mortality and morbidity using the unique personal identification number is performed by linkage to a number of nation-wide disease registries. Follow-up completion rate is almost 100 percent (less than 0.1% have been lost to follow-up mainly through emigration), which is very uncommon for large population studies.

Overview of the patients examined in the Copenhagen City Heart Study:

1. st exam: 1976-78, 19,329 invited, 14,223 (73.6%) attended
2. nd exam: 1981-83, 18,059 invited, 12,698 (71.2%) attended
3. rd exam: 1991-94, 16,563 invited, 10.135 (61.2%) attended
4. th exam: 2001-03,12,600 invited, 6,238 (49.5%) attended
5. th exam: 2011-2014, approx 10,000 invited, approx 5000 (50%) attended

The Copenhagen City Heart Study is governed by a Steering Committee. The data from the Copenhagen City Heart Study is made available to researchers upon application to and approval by the Steering Committee. The following constitute the Steering Committee:

Gorm Jensen and Peter Schnohr (initiators), Peter Lange, Eva Prescott, Børge Nordestgaard, Morten Grønbæk, Anne Tybjærg Hansen, Stig Bojesen, Finn Gyntelberg, Jan Skov Jensen and Merete Appleyard

Inclusion Criteria:

• Background population living in a defined area of Copenhagen

Exclusion Criteria:

• None

Age.stratified random sample of the census population