title: An inverse U-shaped association of late and peak insulin levels during an oral glucose load with glucose intolerance in a Japanese population: a cross-sectional study.
abstract: The current study investigated the association of post-load insulin levels with glucose tolerance in a Japanese population. A total of 1450 Japanese employees who underwent a 75-g oral glucose tolerance test (OGTT) were included. Glucose tolerance was assessed by 120-min glucose levels during a 75-g OGTT. A penalized cubic regression spline model analysis revealed that the 60- and 120-min insulin levels, but not 0- or 30-min insulin levels, had an inverse U-shaped relationship to the 120-min glucose level. Furthermore, peak insulin level followed an inverse U shape in relation to the 120-min glucose level, whereas the peak of insulin appeared at a later point in time as the 120-min glucose level increased. These associations were similarly observed in both obese and non-obese subgroups, although obesity was associated with higher insulin levels. Peak insulin levels also demonstrated an inverse U shape in association with 0-min glucose levels and indices of β cell function, assessed by the disposition index and the β-cell function index. In conclusion, peak insulin levels followed an inverse U shape in relation to glucose intolerance in a Japanese population, whereas the impairment of glucose tolerance was associated with a delay in the time to reach peak insulin levels.
authors.affiliation: Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Takahara
authors.forename: Naoto
authors.initials: N
authors.lastname: Katakami
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Matsuoka
authors.forename: Midori
authors.initials: M
authors.lastname: Noguchi
authors.forename: Iichiro
authors.initials: I
authors.lastname: Shimomura
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D057286:Electronic Health Records; D005260:Female; D018149:Glucose Intolerance / Q000097:blood* / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D008954:Models, Biological; D009765:Obesity / Q000150:complications; D050177:Overweight / Q000150:complications; D011236:Prediabetic State / Q000097:blood* / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology; D012307:Risk Factors
chemical_list: D001786:Blood Glucose; D007328:Insulin