“…To test for trend, the 3 categories were entered in the model as an ordinal variable. We used multiple logistic regression analysis to control for potential confounders, ie, age, sex, glucose tolerance category, known duration of DM of more than 10 years (in the present study a duration effect was seen after 10 years, which is in agreement with other studies 2,5,28 ), HbA 1c level, and hypertension. To exclude the possibility of residual confounding as thoroughly as possible, we also tested models that, in addition, included serum creatinine level, creatinine clearance, hypercholesterolemia, current smoking, body mass index, and/or fasting insulin level.…”