Au580

Blood samples were collected in the morning to analyze aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (γ-GTP), triglyceride (TG), creatinine (CRE), and glucose levels. Blood biomarkers were measured using an automatic biochemical analyzer (AU580; Beckman Coulter, Inc., Tokyo, Japan). Estimated glomerular filtration rate (eGFR) was calculated using the following equation: 194 × Cr^-1094 × age^-0.287 [19 (link)]. HbA1c levels were measured using an ADAMS A1c HA-8180 automatic glycohemoglobin analyzer (Arkray Inc., Kyoto, Japan).
The serum FGF21 concentration was determined using a commercially available ELISA kit (DF2100; R&D Systems, Inc.) according to the manufacturer’s instructions. The mean minimum detectable dose of the assay was 4.67 pg/mL. The intra- and inter-assay coefficients of variation reported by the manufacturer were 2.9%–3.9% and 5.2%–10.9%, respectively.

Social deprivation was determined from the Townsend deprivation index [18 ]. Townsend deprivation index measures area deprivation, comprised of 4 domains including information about unemployment, car ownership, household overcrowding, and owner occupation, derived from the national census data, with higher scores indicate higher levels of social deprivation. The Townsend deprivation index was calculated for participant immediately prior to joining UK Biobank, based on the preceding national census output areas, in which the participant’s postcode is located. Smoking status was self-reported and categorised as never, former, or current smokers. Systolic blood pressure was taken at study baseline using the Omron HEM-7015IT digital blood pressure monitor as the mean of 2 sitting measures. BMI was calculated as the weight of the individual in kilogrammes, measured using the Tanita BC-418 MA body composition analyser, divided by the square of the individual’s standing height in metres. Diabetes status was self-reported: If the age at diagnosis was younger than 30, and the participant was using insulin, they were classified as type 1 diabetes, otherwise as type 2 diabetes. Total cholesterol was measured using the Beckman Coulter AU580. Self-reported medication use was also recorded.