The Third Tromsø Study

The third Tromsø Study (Tromsø3) was carried out in 1986-87 and comprised men in the 20-61 age group (born in 1925-1966) and women in the 20-56 age group (born in 1930-1966), a randomly selected 10 percent from the 12-19 age group (born 1967-1974) and people who were included in the Family Intervention Study, which was carried out after the study in 1979-80.

A total of 10,963 men and 10,863 women participated in the study, which represented 75 percent of the total number invited.

Participation in Tromsø3, 1986-87:

Age	Men invited	Women invited	Male participants	Female participants	% men	% women
12-14	219	242	181	195	82,6	80,6
15-19	522	524	368	390	70,5	74,4
20-24	2076	2102	1160	1303	55,9	62,0
25-29	2211	2194	1318	1572	59,6	71,6
30-34	2327	2367	1583	1848	68,0	78,1
35-39	2261	1987	1710	1681	75,6	84,6
40-44	1893	1722	1485	1526	78,4	88,6
45-49	1318	1177	1076	1059	81,6	90,0
50-54	1048	961	892	874	85,1	90,9
55-59	990	427	836	381	84,4	89,2
60-64	416	36	354	30	85,1	83,3
65-67	0	6	0	4	0	66,7
TOTAL	15281	13745	10963	10863	71,8	79,0

If you do not take into account people who were on temporary leave, had moved or died before the study, the participation rate was 78 percent for men and 85 percent for women.

Examination methods and measurements

A brief questionnaire accompanied the invitation. The questionnaire included questions on diagnosed cardiovascular diseases or diabetes, symptoms of cardiovascular diseases, consumption of salty food and preference of fat type, smoking habits, coffee consumption and physical activity during work and leisure time. This questionnaire was similar to those used in the previous two studies. Measurements of height, weight and blood pressure were taken. A blood sample was also taken to measure serum total cholesterol, HDL cholesterol, triglycerides and gamma-glutamyltransferase (gamma-GT). A simple electrocardiogram (ECG) was also taken. People who attended the study received another questionnaire that they were asked to complete and send back.

What did we discover?

Tromsø 3 confirmed that unfiltered coffee increased serum cholesterol. This study was also the basis for a clinical experiment among 156 women and men with slightly raised blood pressure where it was shown that taking fish oil reduced the blood pressure. This study was published in the New England Journal of Medicine.

We also found that people who developed myocardial infarction had higher levels of homocysteine than healthy people, but a controlled trial (NORVIT-study) performed later has shown that this relationship was not causal.