Routine blood tests were performed for all study participants. Blood samples were collected after overnight fasting, and whole-blood, separated plasma, and serum samples were frozen at −80°C. Blood count, ALT, aspartate transaminase, hemoglobin A1c, glucose, insulin, C-peptide, lactate, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, homocysteine, and high-sensitivity CRP were analyzed using standardized methods at the HUSLAB laboratories.
A 75-g oral glucose tolerance test with four time points (0, 30, 60, and 120 min) was performed after a 12-hour overnight fast, followed by measurements of plasma glucose with spectrophotometric hexokinase and glucose-6-phosphate dehydrogenase assay (Roche Diagnostics) and of serum insulin with time-resolved immunofluorometric assay (PerkinElmer). Free fatty acids were determined with a NEFA kit (Wako Chemicals #999-75406), apolipoprotein B levels with an Apolipoprotein B Konelab kit (Thermo Fisher Scientific, #981663), and plasma adiponectin levels with an enzyme-linked immunosorbent assay (ELISA) kit (R&D Systems, #DHWAD0).
A 75-g oral glucose tolerance test with four time points (0, 30, 60, and 120 min) was performed after a 12-hour overnight fast, followed by measurements of plasma glucose with spectrophotometric hexokinase and glucose-6-phosphate dehydrogenase assay (Roche Diagnostics) and of serum insulin with time-resolved immunofluorometric assay (PerkinElmer). Free fatty acids were determined with a NEFA kit (Wako Chemicals #999-75406), apolipoprotein B levels with an Apolipoprotein B Konelab kit (Thermo Fisher Scientific, #981663), and plasma adiponectin levels with an enzyme-linked immunosorbent assay (ELISA) kit (R&D Systems, #DHWAD0).