The sixth survey of the Tromsø Study (Tromsø6) was conducted in 2007-08. A total of 12984 men and women aged 30-87 took part. The invited population consisted of four groups: Subjects who took part in the special study in the Tromsø 4, a 10 % random sample of subjects aged 30-39, all individuals aged 40-42 or 60-87 and a 40 % random sample of subjects aged 43-59 years. A total of 12984 men and women (65,7 % of the invited population) attended the survey.
The more detailed description of the sixth survey has been described in a Cohort Profile paper
| Age | Men invited | Women invited | Male participants | Female participants | % men | % women |
| 30-34 | 242 | 257 | 90 | 130 | 37,2 | 50,6 |
| 35-39 | 302 | 284 | 122 | 167 | 40,4 | 58,8 |
| 40-44 | 2036 | 2047 | 1075 | 1292 | 52,8 | 63,1 |
| 45-49 | 952 | 922 | 588 | 621 | 61,8 | 67,4 |
| 50-54 | 855 | 905 | 534 | 666 | 62,5 | 73,6 |
| 55-59 | 847 | 800 | 613 | 623 | 72,4 | 77,9 |
| 60-64 | 1634 | 1581 | 1165 | 1281 | 71,3 | 81,0 |
| 65-69 | 1068 | 1054 | 830 | 827 | 77,7 | 78,5 |
| 70-74 | 691 | 745 | 516 | 549 | 74,7 | 73,7 |
| 75-79 | 506 | 711 | 325 | 439 | 64,2 | 61,7 |
| 80-84 | 372 | 604 | 162 | 261 | 43,5 | 43,2 |
| 85-87 | 120 | 227 | 34 | 74 | 28,3 | 32,6 |
| TOTAL | 9625 | 10137 | 6054 | 6930 | 62,9 | 68,4 |
The attendance rate among the subjects who had taken part in the special study in Tromsø4 was high, 74 % of 5759 subjects, whereas it was lower (62 %) in the other groups of the invited population.
All the invited subjects were given information about the study. A questionnaire (4 pages) was mailed together with the invitation. The questionnaire included questions about general health status, diseases and diseases in the family, muscle pain, physical discomfort and mental distress, use of the public health service and medications, socioeconomic situation, physical activity in leisure time, smoking and alchol habits as well as food habits. Women were asked about, among other topics, parity, age at menarche and age at menopause. People who attended the study received another very comprehensive questionnaire that they were asked to complete and send back.
Everyone who attended underwent a relatively simple medical examination comprising measuring height, weight, waist and hip circumference and blood pressure. A blood sample was also taken to measure serum total cholesterol, HDL-cholesterol, triglycerides and glucose.
All individuals who had taken part in the special study in Tromsø4, who were aged 50-62 or 75-84 as well as a 20 % random sample of subjects aged 63-74 were invited to a more comprehensive examionation in the same way as in the Tromsø4 and Tromsø5 surveys.