Effect of repetitive health examinations on blood sugar levels: the Zagreb preliminary study.

In this study recruitment rates of subjects with borderline glucose tolerance were investigated (using the specific procedure described below) and were shown to be 1.8% of the population approached and 2.5% of the population screened. 75 g glucose load yielded higher numbers of subjects with borderline glucose tolerance levels at screening than a 50 g glucose load. However, the numbers of the people finally recruited into the cohort by confirmatory screening were the same when only the 50 g load was used at confirmatory screenings. Subjects recruited in this way remained in the study for 24 months. Repeated health checks had an effect of lowering concentrations of blood glucose after an oral load in treated and control groups, and in those with borderline and those with normal blood glucose values at the initial screening. It is concluded that the process of screening and observation itself has an effect upon glucose tolerance, independent of formal 'treatment'.