title: Influence of increasing BMI on insulin sensitivity and secretion in normotolerant men and women of a wide age span.
abstract: The impact of sex and age on glucose metabolism in the development of overweight/obesity is a matter of debate. We hypothesized that insulin sensitivity (IS) and β-cell function (BF) in a normal white population will differ between males and females and aimed to evaluate the possible effects of BMI and age on metabolic parameters of both sexes. This study is a cross-sectional analysis of the general community. IS was measured with quantitative insulin sensitivity check index (QUICKI) and oral glucose insulin sensitivity (OGIS) and BF with the insulinogenic index during 75-g 2-h oral glucose-tolerance tests (OGTTs). We studied 611 females and 361 males with normal glycemia according to both fasting and 2-h glucose (85 ± 0.3 mg/dl (means ± SE) in females and 89 ± 0.4 in males (P < 0.0001), and 93 ± 1 in females and 89 ± 1 in males (P = 0.005), respectively). Females were younger (37 ± 1 years) than males (40 ± 1, P < 0.0001), but no difference was found in mean BMI (BMI = 25.8 ± 0.2 kg/m(2) in both). Student's two-sample t-test was used for simple comparison between and within genders, multiple linear regressions to account for covariates. During the OGTT, females had lower glucose (area under the curve (AUC) 133 ± 1 mg/ml·2 h vs. 148 ± 2; P < 0.00001), while insulinemia was comparable (AUC 5.3 ± 0.1 mU/ml·2 h vs. 5.7 ± 0.2, P = 0.15). IS remained higher in females (473 ± 3 ml/min/m(2) vs. 454 ± 3, P < 0.0001) also after having accounted for age and BMI (P = 0.015). No difference was observed in fasting insulin or BF. However, BF increased by 46% with BMI and when accounting for age and BMI, BF of females was significantly higher (P < 0.0001). Because IS and BF are higher in females than in males, sex should be considered in metabolic studies and overweight/obese populations.
authors.affiliation: Gender Medicine Unit, Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria. alexandra.kautzky-willer@meduniwien.ac.at
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kautzky-Willer
authors.forename: Alessandra R
authors.initials: AR
authors.lastname: Brazzale
authors.forename: Ermanno
authors.initials: E
authors.lastname: Moro
authors.forename: Jana
authors.initials: J
authors.lastname: Vrbíková
authors.forename: Běla
authors.initials: B
authors.lastname: Bendlova
authors.forename: Stefano
authors.initials: S
authors.lastname: Sbrignadello
authors.forename: Andrea
authors.initials: A
authors.lastname: Tura
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pacini
mesh_terms: D000328:Adult; D017677:Age Distribution; D001317:Austria / Q000453:epidemiology; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D018153:Czech Republic / Q000453:epidemiology; D005215:Fasting / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D007333:Insulin Resistance; D000078790:Insulin Secretion; D007558:Italy / Q000453:epidemiology; D008297:Male; D009765:Obesity / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D019518:Postprandial Period; D017678:Sex Distribution
chemical_list: D001786:Blood Glucose; D007328:Insulin