Au400e chemistry analyzer

Fat mass (FM) and fat-free mass (FFM) were measured using whole body air displacement plethysmography (BodPod, Life Measurement, USA) with the Pediatric Option [30 (link)]. Offspring weight was measured using an electronic scale. Triceps, subscapular and mid-thigh skin-fold thicknesses were measured using Lange Skin-fold Calipers (Beta Technology, USA) to the nearest 1.0 mm by trained nurses. Body composition measurements for each participant were taken in triplicate and the mean of the two closest measures was used for analyses. Skinfolds were summed (sum of skinfolds) as a measure of subcutaneous adiposity. Age-specific BMI z scores were calculated according to the World Health Organization growth reference [31 , 32 ].
Fasting triacylglycerols (TAGs), total cholesterol, HDL, LDL and glucose were measured using manufacturer-prepackaged enzymatic kits and the AU400e Chemistry Analyzer (Olympus America, USA). Insulin was measured using a radioimmune assay, and leptin and adiponectin were measured using a Multiplex assay kit, all by Millipore (USA). We calculated the ratio of TAGs:HDL as an indicator of an atherogenic lipid profile and a strong correlate of insulin resistance [33 (link), 34 (link)], 1/(fasting insulin) as a measure of insulin sensitivity [35 (link)] and an updated HOMA-IR [36 (link)]. The inter-assay CVs of these biomarkers were all <6.0%.

Infant metabolic markers were measured in cord blood drawn at the time of delivery and processed by the University of Colorado Clinical and Translational Sciences Institute (CCTSI) Core Lab. Insulin (µU/mL) in serum and plasma was measured using radioimmunoassay (EMD Millipore Corporation, Billerica, MA). Glucose (mg/dl), cholesterol (mg/dl), HD-cL total (mg/dl), non-HDL-c (mg/dl), triglycerides (mg/dl), and free fatty acids (µmol/l) were measured using manufacture prepackaged enzymatic kits and the AU400e Chemistry Analyzer (Olympus America, Center Valley, PA). Cord serum leptin levels were determined by ELISA (Alpco, Salem, NH). We calculated insulin sensitivity as the ratio of neonatal glucose and insulin as described previously^{9 (link),14 (link),15 (link)}.

Fasting glucose was measured using manufacturer pre-packaged enzymatic kits and the AU400e Chemistry Analyzer (Olympus America), and insulin was measured using an RIA by Millipore Corporation (USA). We calculated 1/(fasting insulin) as a measure of insulin sensitivity[12 (link)] and calculated an updated HOMA (HOMA2-IR and HOMA2-B)[13 (link)].

At median 17 (range 11–20) and 27 (range 20–34) gestational weeks, fasting blood was drawn from the women. Our primary exposure of interest was HbA_1c, assayed from blood collected at 27 weeks, measured using a potassium ferricyanide assay by DCA Vantage Analyzer (Siemens, USA). Our secondary exposure was glucose concentrations measured at both time points using manufacturer pre-packaged enzymatic kits and the AU400e Chemistry Analyzer (Olympus America, USA).