The seventh survey of the Tromsø Study (Tromsø 7) was carried out in 2015 and 2016. An invitation was sent to 32 591 people from the age of 40 years and older. In total, 21 083 men and women between the ages of 40 to 99 years participated (65% attendance).
Table 1: Participation, Tromsø 7
|Age||Men invited||Women invited||Male participants||Female participants||% men||% women|
All inhabitants in Tromsø municipality aged 40 years and older were sent an invitation by mail. The invitation included a comprehensive study information brochure, the questionnaire Q1 in paper-version, and a username and password for the digital version of questionnaire Q1 (for those who preferred this instead of paper),questionnaire Q2 and the graphical index of pain questionnaire (electronic versions only). By using the username and password, the participants could log into a questionnaire portal, and complete the questionnaires. When attending at the Tromsø 7 examination site, the participants also received a comprehensive dietary questionnaire (FFQ) in paper-version to complete and return by mail. Many participants completed the FFQ before leaving the examination site. At the examination site, technical assistance to complete questionnaires were available, including oral English translation (English only). Information about the availability of technical assistance at site was given in the brochure and through media during the entire period of the Tromsø 7 data collection period.
All the participants in Tromsø 7, went through a basic examination (first visit), which consisted of anthropometric measurements (height, weight, waist and hip circumference), blood pressure, heart rate and oxygen saturation, and biological sampling. Biological sampling included blood samples (for analysis of blood lipids, HbA1c, creatinine and many other), and in sub-samples, nose-throat samples and saliva. In addition, a clinical examination of pain sensitivity was conducted on all participants, and a clinical dental examination was conducted on a sub-sample (n=3800).
A pre-defined sample of 13 000 people were invited for a second visit including extended comprehensive examinations (second visit). The sample were randomly selected, with the exception of additionally including former Tromsø Study participants not already selected in the random selection process. Inviting people for a second visit was also done in Tromsø 4, Tromsø 5 and Tromsø 6. The sample selected for the second visit were given equipment to collect 3 days of urine and stool samples. At the second visit, more blood samples were taken including samples for RNA-analysis. Other tests included ECG, ultrasound carotid assessment, echocardiography, eye examinations, lung function tests (spirometry and pulse oximetry), recording of heart and lung sounds, DEXA-measurements of bone mineral density and body composition, physical function tests including grip strength and balance, as well as cognitive function tests. In addition, an accelerometer was handed out for a one-week data collection of objective measurement of physical activity.