Study Design
The study had a double-blind, randomized, placebo-controlled design. Thirty-two patients with diabetes type 2 and 32 healthy controls were randomized to one of two groups in a double-blind manner: a) conditioned group and b) control group. Men and women were equally distributed between the groups. This study was an adaptation of the study design used by Stockhorst and colleagues (The study was approved by the Medical Ethical Committee of Leiden, Den Haag, Delft, under protocol number P18.222.Randomization was performed by the Department of Clinical Pharmacy of the Leiden University Medical Center. A block randomization was used with a size of eight participants per block. Equal numbers of men and women were randomized to each condition. The pharmacy was responsible for assigning participants to the conditions. The experimenter was blinded regarding the conditions, and the list coupling participants numbers with conditions remained at the pharmacy until the last participant was tested.