Glucose 201 rt

The Dexcom G5 Platinum system (Dexcom, San Diego, CA) was used during the study period. The sensors were inserted and calibrated according to company recommendation. The rtCGM devices and insulin pumps were downloaded via Diasend (Glooko Inc., Mountain View, CA) downloading system. HemoCue Glucose 201 RT (HemoCue, Ängelholm, Sweden), glucose measuring range 0–180 mg/dl (0–24.6 mmol/l), coefficient of variation (CV) 1.8%, was used for calibration of the rtCGM. All participants utilized the information they received via rtCGM but received no further instructions on glucose management during the race.
Each participant was informed to take proactive actions against hyperglycemia, >180 mg/dl (>10 mmol/l) as well as against hypoglycemia, <72 mg/dl (<4 mmol/l).
Hyperglycemia: Glucose value >180 mg/dl (>10 mmol/l) and stable alternatively increasing trend—Action: Bolus correction aiming at 108 mg/dl (6 mmol/l) taking into account a doubled Insulin Sensitivity Factor (ISF) during exercise.
Hypoglycemia: Glucose value 86.4–102.6 mg/dl (4.8–5.7 mmol/l) + arrow trend obliquely downwards, 102.6–117 mg/dl (5.7–6.5 mmol/l) + single arrow downwards and 117 mg/dl (>6.5 mmol/l) + double arrow downwards—Action: Immediate response by extra CHO-intake (about 20–25 g) or to use a 30-min insulin pump suspension.

The participants arrived at the laboratory at 07.00 after an overnight fast. A venflon (BD Venflon TM Pro, Helsingborg, Sweden) was inserted in the antecubital vein, and a fasting blood sample was taken. Then the subjects ingested 3 mg‧kg⁻¹ caffeine or a placebo drink. After 30 min, a new blood sample was taken (time 0) before the subjects ingested 75 g glucose dissolved in 3 dL of water. Blood samples were then taken at 15, 30, 60, 90, 120 and 180 min after glucose intake. After each blood test, the venflon was rinsed with saline solution (NaCl 0.9%, B. Braun Melsungen AG, Melsungen, Germany). Blood samples were obtained in EDTA tubes and kept on ice until centrifugation (3500× g at 4 °C for 10 min). After centrifugation, plasma was pipetted into Eppendorf tubes and stored at −80 °C. Serum blood samples for analysis of C-peptide were obtained at 0, 30 and 120 min. Serum tubes were allowed to coagulate for 30–40 min at room temperature and centrifuged (3500× g at 4 °C for 10 min). C-peptide was analyzed by Fürst Medisinsk Laboratorium (Fürst Medisinsk Laboratorium, Oslo, Norway). Venous blood glucose was analyzed immediately (HemoCue Glucose 201 RT; Ängelholm, Sweden). Due to problems with the venflon, glucose was measured in capillary blood for one of the participants. Area under the curve (AUC) for glucose and C-peptide was calculated with the trapezoid method.

Serum lipid and apolipoprotein levels were measured using the Cobas Integra 400 Plus analyzer (Roche, Basel, Switzerland) with Roche ‘closed’ reagents (Roche, Manheim, Germany). HDL-C and LDL-C were each directly measured with homogeneous colorimetric assays using HDL-C plus 3^rd generation and LDL-C plus 2^nd generation reagents. Triglycerides and TC were measured using an enzymatic colorimetric assay (triglyceride and TC generation 2 reagents), and apoA1 and apoB levels by an immunoturbidimetric assay (Tina-quant version 2 reagents). External quality assurance for apoA and apoB was conducted by the College of American Pathologists. The MRC/UVRI and London School of Hygiene and Tropical Medicine laboratory, where all lipid assays were performed, has been certified for good clinical laboratory practice since 2009.
As previously reported [17 (link)] we tested venous blood samples in the field for RBG using Accu-Check® Aviva (Roche Diagnostics GmbH, Mannheim, Germany) and FBG using HemoCue® Glucose 201 RT (HemoCue AB, Ängelholm, Sweden).

Whole venous blood was tested for RBG using a portable-battery driven Accu-Check® Aviva (Roche Diagnostics GmbH, Mannheim, Germany) and FBG using HemoCue® Glucose 201 RT (HemoCue AB, Ängelholm, Sweden). HIV testing was performed using approved testing algorithms in each country. In both countries, Determine™ HIV1/2 (Alere Medical Co. Ltd., Mitsudo-shi, Chiba, Japan) was used as a first-line test and negative results were recorded as such. Positive samples were confirmed by Uni-Gold™ HIV (Trinity Biotech, Plc, Bray, Co.Wicklow, Ireland) in Tanzania and HIV 1/2 STAT-PAK® (Chembio Diagnostic Systems Inc, Medford, NY, USA) in Uganda. In case of discrepant results, HIV 1/2 STAT-PAK® in Tanzania and Uni-Gold™ HIV in Uganda were used as tiebreakers.