Total cholesterol, LDL-cholesterol, HDL-cholesterol and TAG
Serum cholesterol concentrations were measured using the Alinity c Cholesterol Assay kit (Abbott GmbH & Co) according to the manufacturer’s instructions. Briefly, cholesterol esters were enzymatically hydrolysed by cholesterol esterase to cholesterol and NEFA (intra-assay CV was 1·0 %). The Alinity c Direct LDL Assay kit (Sekisui Diagnostics P.E.I. Inc) was used for the direct, quantitative determination of LDL-cholesterol in human serum (intra-assay CV was 0·8 %). Serum HDL-cholesterol concentrations were measured using the Ultra HDL Assay kit (Abbott GmbH & Co). This assay is a homogeneous method in which HDL-cholesterol concentrations are measured without the need for off-line pre-treatment or centrifugation steps (intra-assay CV was 1·0 %). Finally, the Alinity c Triglyceride Assay (Abbott GmbH & Co) was used for the quantitation of TAG in human serum. With this method, TAG are enzymatically hydrolysed by lipase to NEFA and glycerol (intra-assay CV was 1·8 %).