Adivia1650

Fasting glucose concentrations were determined according to standard procedures using an ADIVIA1650 (Siemens, Washington, DC, USA) in 2007, a Hitachi Automatic Analyzer 7600 (Hitachi, Tokyo, Japan) in 2008–2010, and Labospect 008AS (Hitachi, Tokyo, Japan) in 2019–2020. Insulin concentrations were measured using an immunoradiometric assay (INS-IRMA; Biosource, Nivelles, Belgium) with a 1470 WIZARD gamma-counter (PerkinElmer, Turku, Finland) in 2007–2010 and using an electrochemiluminescence immunoassay (ECLIA; Roche, Germany) with modular E801 (Roche, Germany) in 2019–2020. The assay detection limit was 1 μU/mL, and the intra- and inter-assay coefficients of variation were 2.2% and 6.5%, respectively. Insulin sensitivity was evaluated using the HOMA-IR index with the following equation: HOMA-IR=fasting insulin (μU/mL)×fasting glucose (mg/dL)/405.

After 5 min of rest in a seated position, blood pressure was measured manually 3 times with 30 s intervals. Body mass index (BMI) was calculated by weight in kilograms divided by height in meters squared.
Blood samples were collected after fasting for at least 8 h and random spot urine samples were collected on the same visit. After being properly processed and refrigerated, they were transported in cold storage to the central laboratory within 24 h of collection. Glucose levels were measured using the hexokinase ultraviolet method with a Hitachi Automatic Analyzer 7600-210 (Hitachi, Marunouchi, Japan). Hemoglobin A1c (HbA1c) levels were measured with a high-performance liquid chromatography assay with a Tosoh G8 instrument (Tosoh, Shiba, Japan) [17 (link)]. Serum creatinine levels were measured by the colorimetric method using ADIVIA 1650 (Siemens, Malvern, PA, USA) in 2007 and the Jaffe rate-blanked and compensated method using the Hitachi Automatic Analyzer 7600 (Hitachi, Tokyo, Japan) in 2008–2018. Serum creatinine concentrations were calibrated to isotope-dilution mass spectrometry-traceable standard.

Trained personnel measured the body weight and height using standard protocols to the nearest 0.1 kg and 0.1 cm, respectively. Blood pressure was manually measured using a mercury sphygmomanometer, and the values were corrected based on height of the arm during measurement, which was in accordance with the recommendation by the American Heart Association [22 (link)].
Blood samples were taken only if the participant had fasted for at least 8 h. Triglycerides (TG), HDL cholesterol, and fasting glucose were measured using ADIVIA1650 (Siemens/USA) from July 2007 to February 2008 and Hitachi Automatic Analyzer 7600 (Hitachi/Japan) from February 2008 to December 2012. Each measured HDL cholesterol value was corrected by the Lipid Standardization Program (LSP), as recommended by the Centers for Disease Control and Prevention. In each session, serum insulin was measured using the Gamma Counter (Hewlett Packard/USA) and 1470 WIZARD Gamma Counter (PerkinElmer/Finland).