H 7600 autoanalyzer

A lipid profile [i.e., TC, TG, HDL-C, LDL-C, apolipoprotein (apo) A-I, apoB, apoE, and lipoprotein (a)] and serum glucose were measured in the hospital clinical laboratory using an H-7600 autoanalyzer (Hitachi, Tokyo, Japan). Fasting serum insulin was measured using an immunoradiological method. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated by the following formula: HOMA-IR = fasting serum insulin (μU/mL) × fasting plasma glucose (mmol/L)/22.539 (link).

After fasting for at least 8 h, a fasting blood sample was drawn from the antecubital vein in the morning. Cholesterol concentrations were directly measured using the VerticalAuto Profile (Atherotech, London, UK), an inverted rate-zonal, single-vertical spin, density-gradient ultracentrifugation technique that separates lipoprotein subfractions and measures the levels of LDL-C, very low-density lipoprotein cholesterol (VLDL-C), and high-density lipoprotein cholesterol (HDL-C). Non-HDL-C, calculated as total-C - HDL-C, is the total quantity of cholesterol carried by all potentially atherogenic, apo B-containing lipoprotein particles, including LDL, IDL, Lp(a), VLDL (including VLDL remnants), chylomicron particles and remnants. The serum glucose level was measured using an H-7600 autoanalyzer (Hitachi, Tokyo, Japan).

For each participant, a fasting blood sample was drawn from the antecubital vein. Serum lipid profiles (including TC, TG, HDL-C, LDL-C, apoA-I, apoB, apoE and Lp(a), fasting serum glucose, and fasting serum insulin were measured. Serum lipid profiles were measured in the hospital laboratory using routine procedures; serum glucose was measured using an H-7600 autoanalyzer (Hitachi, Tokyo, Japan), and serum insulin was measured using an immunoradiology method. Insulin resistance was calculated using HOMA-IR as: fasting serum insulin (μU/mL) × fasting plasma glucose (mmol/L)/22.542 (link). Dyslipidemia, in terms of TC, TG, HDL-C, LDL-C, apoA-I, apoB, apoE, and Lp(a), was defined as ≥5.17 mmol/L, ≥1.7 mmol/L, <1.03 mmol/L, ≥3.33 mmol/L, <1.2 g/L, >1.1 g/L, >0.05 g/Lor <0.03 g/L, and ≥0.3 g/L, respectively, according to the diagnostic criteria of the US National Cholesterol Education Program Adult Treatment Panel III (NCEPIII)43 (link) and Joint Committee for Developing Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults (JCDCG)44 (link).

Fasting blood samples were also collected in the morning after monitoring by PSG. Serum glucose concentrations were measured with a Hitachi H-7600 Autoanalyzer (Tokyo, Japan). Diabetes was defined as a combination of a fasting plasma glucose level of ≥7.0 mmol/L, a previous diabetes diagnosis, or treatment with an anti-diabetic medication 1 week before measurement.