The first survey of the Tromsø Study (Tromsø1) was carried out in 1974 and comprised only men in the 20-49 age groups (born in 1925-1954). As men have a much higher rate of contracting, and dying as a result of, cardiovascular diseases, the decision was made to include only men in this first Tromsø Study.
A total of 8866 men were invited to participate in Tromsø1, and of these 6595 (74 percent) participated in the study.
| Age | Invited | Participants | % |
| 20-24 | 1662 | 1014 | 61,0 |
| 25-29 | 1996 | 1374 | 68,8 |
| 30-34 | 1741 | 1321 | 75,9 |
| 35-39 | 1249 | 1022 | 81,8 |
| 40-44 | 1095 | 929 | 84,8 |
| 45-49 | 1123 | 935 | 83,2 |
| TOTAL | 8867 | 6595 | 74,4 |
If you do not take into account people who were temporarily away from Tromsø, the participation rate was an impressive 83 percent.
A brief questionnaire accompanied the invitation. The questionnaires included questions on diagnosed cardiovascular diseases or diabetes, symptoms of cardiovascular diseases, smoking habits and physical activity during work and leisure time. A brief interview was also conducted, and measurements of height, weight and blood pressure were taken. A blood sample was also taken to measure serum total cholesterol, triglycerides and haemoglobin.
The best-known research result from Tromsø 1 is the demonstration of a relatively high level in the serum of HDL-cholesterol ("the good cholesterol") that helps to prevent myocardial infarction. In 1977, this was the Norway's most frequently referred to scientific work within medicine, and over the years this discovery has been referred to on more than 1100 occasions in specialist medical literature.