All participants in the first investigation (at age 50), traced by their ten-digit social security number, were invited to reinvestigation (including non-participants at age 60). Participation rate was 73% (1221 of 1681). The survey was carried out between August 1991 and May 1995.
During the intervening 20 years 422 had died and 219 had moved out of the Uppsala region. Of the 1681 men invited, 460 did not participate in this follow up, leaving 1221 men aged around 70.
Investigation programme
Procedures were carried out in a manner as similar as possible to the two previous surveys, including a medical questionnaire, blood pressure and anthropometric measurements, blood samples, per oral glucose tolerance test, hyperinsulinaemic euglycaemic clamp and 24-hour ambulatory blood pressure registration.